U.S. patent application number 14/783707 was filed with the patent office on 2016-03-17 for tetrahydrofuran derivatives and use thereof as plasticizers.
The applicant listed for this patent is BASF SE. Invention is credited to Martin A. BOHN, Boris BREITSCHEIDEL, Alois KINDLER, Benoit LANK, Jochen WAGNER.
Application Number | 20160075671 14/783707 |
Document ID | / |
Family ID | 48095691 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160075671 |
Kind Code |
A1 |
WAGNER; Jochen ; et
al. |
March 17, 2016 |
TETRAHYDROFURAN DERIVATIVES AND USE THEREOF AS PLASTICIZERS
Abstract
The invention relates to tetrahydrofuran derivatives of general
formula (I), wherein X stands for *--(C.dbd.O)--O--, *--(CH2)n-O--,
or *--(CH2)n-O--(C.dbd.O)--, wherein * represents the point of
bonding to the tetrahydrofuran ring and n has the value 0, 1, or 2;
and R1 and R2 are selected independently of each other from among
C4-C5 alkyl and C5-C6 cycloalkyl, wherein the cycloalkyl groups are
unsubstituted or can be substituted by at least one C1-C10 alkyl
group, a plasticizer composition that contains said tetrahydrofuran
derivatives, molding masses that contain a thermoplastic polymer or
an elastomer and such a tetrahydrofuran derivative. The invention
further relates to a method for producing said tetrahydrofuran
derivatives, and to the use of said tetrahydrofuran derivatives
Inventors: |
WAGNER; Jochen;
(Ruppertsweiler, DE) ; BREITSCHEIDEL; Boris;
(Waldsee, DE) ; BOHN; Martin A.; (Mannheim,
DE) ; LANK; Benoit; (Edingen-Neckarhausen, DE)
; KINDLER; Alois; (Grunstadt, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BASF SE |
Ludwigshafen |
|
DE |
|
|
Family ID: |
48095691 |
Appl. No.: |
14/783707 |
Filed: |
April 11, 2014 |
PCT Filed: |
April 11, 2014 |
PCT NO: |
PCT/EP2014/057411 |
371 Date: |
October 9, 2015 |
Current U.S.
Class: |
524/111 ;
106/503; 106/505; 549/485; 549/502 |
Current CPC
Class: |
C07D 307/12 20130101;
C07D 307/24 20130101; C08K 5/1535 20130101; H04W 88/08 20130101;
H04B 7/0473 20130101; C08K 5/11 20130101; H04B 7/155 20130101; C08K
5/42 20130101 |
International
Class: |
C07D 307/12 20060101
C07D307/12; C08K 5/42 20060101 C08K005/42; C08K 5/11 20060101
C08K005/11; C07D 307/24 20060101 C07D307/24; C08K 5/1535 20060101
C08K005/1535 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2013 |
EP |
13163577.3 |
Claims
1. A thermoplastic polymer or elastomer comprising at least one
plasticizer of the general formula (I), or of a plasticizer
composition comprising at least one plasticizer of the general
formula (I) and at least one plasticizer that is not of the general
formula (I) ##STR00006## in which X is *--(C.dbd.O)--O--,
*--(CH.sub.2).sub.n--O-- or *--(CH.sub.2).sub.n--O--(C.dbd.O)--,
where * is the point of linkage to the tetrahydrofuran ring, and n
has the value 0, 1, or 2; and R.sup.1 and R.sup.2 have been
selected mutually independently from C.sub.4-C.sub.5-alkyl and
C.sub.5-C.sub.6-cycloalkyl, where the cycloalkyl moieties are
unsubstituted or can have substitution by at least one
C.sub.1-C.sub.10-alkyl moiety.
2. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer of the general formula (I), R.sup.1 and
R.sup.2 are independently selected from an unbranched or branched
C.sub.4-alkyl moiety.
3. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer of the general formula (I), R.sup.1 and
R.sup.2 are independently selected from n-butyl or isobutyl.
4. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer of the general formula (I), both of the
groups X are *--(C.dbd.O)--O--.
5. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer that is not of the formula (I), is a
plasticizer for a thermoplastic polymer which comprises polyvinyl
chloride or consists of polyvinyl chloride.
6. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer that is not of the formula (I), is a
plasticizer for an elastomer which comprises a natural and/or
synthetic rubber or consists of a natural and/or synthetic
rubber.
7. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer that is not of the formula (I), is
plastisol.
8. The polymer or elastomer according to claim 1, wherein the at
least one plasticizer of the general formula (I) reduces the
temperature required for the gelling of a thermoplastic polymer,
and/or for increasing the gelling rate.
9. The polymer or elastomer according to claim 1, wherein the
plasticizer that is not of the formula (I) is selected from dialkyl
phthalates, alkyl aralkyl phthalates, dialkyl terephthalates,
trialkyl trimellitates, dialkyl adipates, alkyl benzoates,
dibenzoic esters of glycols, hydroxybenzoic esters, esters of
saturated mono- and dicarboxylic acids, esters of unsaturated
dicarboxylic acids, amides and esters of aromatic sulfonic acids,
alkylsulfonic esters, glycerol esters, isosorbide esters,
phosphoric esters, citric triesters, alkylpyrrolidone derivatives,
2,5-furandicarboxylic esters, epoxidized vegetable oils based on
triglycerides and saturated or unsaturated fatty acids, or
polyesters derived from aliphatic and/or aromatic polycarboxylic
acids with at least dihydric alcohols.
10. A plasticizer composition comprising at least one compound of
the general formula (I) as defined in claim 1, and at least one
plasticizer that is not of the general formula (I).
11. The plasticizer composition according to claim 10, where the
plasticizer that is not of the general formula (I) is selected from
dialkyl phthalates, alkyl aralkyl phthalates, dialkyl
terephthalates, trialkyl trimellitates, dialkyl adipates, alkyl
benzoates, dibenzoic esters of glycols, hydroxybenzoic esters,
esters of saturated mono- and dicarboxylic acids, esters of
unsaturated dicarboxylic acids, amides and esters of aromatic
sulfonic acids, alkylsulfonic esters, glycerol esters, isosorbide
esters, phosphoric esters, citric triesters, alkylpyrrolidone
derivatives, 2,5-furandicarboxylic esters, epoxidized vegetable
oils based on triglycerides and saturated or unsaturated fatty
acids, or polyesters derived from aliphatic and/or aromatic
polycarboxylic acids with at least dihydric alcohols.
12. A compound of the general formula (I) ##STR00007## in which X
is *--(C.dbd.O)--O--, *--(CH.sub.2).sub.2--O-- or
*--(CH.sub.2)--O--(C.dbd.O)--, where * is the point of linkage to
the tetrahydrofuran ring; and R.sup.1 and R.sup.2 are independently
selected from n-butyl or isobutyl.
13. The compound according to claim 12, where both the groups X are
*--(C.dbd.O)--O--.
14. A molding composition comprising at least one polymer and at
least one plasticizer of the general formula (I) as defined in
claim 12.
15. A molding composition comprising at least one polymer and a
plasticizer composition as defined in claim 10.
16. The molding composition according to claim 14, where the
polymer is a thermoplastic polymer selected from homo- and
copolymers which comprise at least one copolymerized monomer
selected from C.sub.2-C.sub.10-monoolefins, 1,3-butadiene,
2-chloro-1,3-butadiene, vinyl alcohol and its
C.sub.2-C.sub.10-alkyl esters, vinyl chloride, vinylidene chloride,
vinylidene fluoride, tetrafluoroethylene, glycidyl acrylate,
glycidyl methacrylate, acrylates and methacrylates of
C.sub.1-C.sub.10-alcohols, vinylaromatics, (meth)acrylonitrile,
maleic anhydride, and .alpha.,.beta.-ethylenically unsaturated
mono- and dicarboxylic acids, homo- and copolymers of vinyl
acetals, polyvinyl esters, polycarbonates, polyesters, polyethers,
polyether ketones, thermoplastic polyurethanes, polysulfides,
polysulfones, polyether sulfones, cellulose alkyl esters, or any
one mixtures thereof.
17. The molding composition according to claim 16, where the
thermoplastic polymer is selected from polyvinyl chloride (PVC),
polyvinyl butyral (PVB), homo- and copolymers of vinyl acetate,
homo- and copolymers of styrene, polyacrylates, thermoplastic
polyurethanes (TPUs), or polysulfides.
18. The molding composition according to claim 16, where the
thermoplastic polymer is polyvinyl chloride (PVC).
19. The molding composition according to claim 18, comprising at
least one plasticizer of the general formula (I) ##STR00008## in
which X is *--(C.dbd.O)--O--, *--(CH.sub.2).sub.2--O-- or
*--(CH.sub.2)--O--(C.dbd.O)--, where * is the point of linkage to
the tetrahydrofuran ring; and R.sup.1 and R.sup.2 are independently
selected from n-butyl or isobutyl, where the total plasticizer
content is from 1.0 to 400 phr (parts by weight per 100 parts by
weight of polymer).
20. The molding composition according to claim 16, comprising at
least one thermoplastic polymer different from polyvinyl chloride,
at least one plasticizer of the general formula (I) ##STR00009## in
which X is *--(C.dbd.O)--O--, *--(CH.sub.2).sub.2--O-- or
*--(CH.sub.2)--O--(C.dbd.O)--, where * is the point of linkage to
the tetrahydrofuran ring; and R.sup.1 and R.sup.2 are independently
selected from n-butyl or isobutyl, where the total plasticizer
content is from 0.5 to 300 phr (parts by weight per 100 parts by
weight of polymer).
21. The molding composition according to claim 14, where the
polymer is an elastomer selected from natural rubbers, synthetic
rubbers, or mixtures thereof.
22. The molding composition according to claim 21, comprising at
least one compound of the general formula (I) as defined in 11
claim 12, where the total plasticizer content is from 1.0 to 60 phr
(parts by weight per 100 parts by weight of polymer).
23. A process for producing compounds of the general formula (I.1),
##STR00010## in which R.sup.1 and R.sup.2 are independently
selected from n-butyl or isobutyl, where a) optionally
2,5-furandicarboxylic acid or an anhydride or acyl halide thereof
is reacted with a C.sub.1-C.sub.3-alkanol in the presence of a
catalyst to give a di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate, b1) 2,5-furandicarboxylic acid or an
anhydride or acyl halide thereof, or the di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate obtained in step a), is reacted with
n-butanol and/or isobutanol in the presence of at least one
catalyst to give a compound of the formula (I.1a), ##STR00011## c1)
the compound (I.1a) obtained in step b1) is hydrogenated with
hydrogen in the presence of at least one hydrogenation catalyst to
give the compound of the general formula (I.1), or b2)
2,5-furandicarboxylic acid or the di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate obtained in step a) is hydrogenated with
hydrogen in the presence of at least one hydrogenation catalyst to
give a compound of the general formula (I.1b), ##STR00012## c2) the
compound (I.1b) obtained in step b2) is reacted with n-butanol
and/or isobutanol in the presence of a catalyst to give a compound
of the formula (I.1).
24. A process for producing compounds of the general formula (I.2)
or (I.3), ##STR00013## in which R.sup.1 and R.sup.2 are
independently selected from n-butyl or isobutyl, where a)
2,5-di(hydroxyethyl)tetrahydrofuran is reacted with at least one
alkylating reagent R.sup.1--Z and, if R.sup.1 and R.sup.2 are
different, also with at least one alkylating reagent R.sup.2--Z,
where Z is a leaving group, in the presence of a base to give
compounds of the formula (I.2), or b)
2,5-di(hydroxymethyl)tetrahydrofuran is reacted with at least one
acyl halide R.sup.1--(C.dbd.O)X and, if R.sup.1 and R.sup.2 are
different, with at least one acyl halide R.sup.2--(C.dbd.O)X, where
X is Br or Cl, in the presence of at least one tertiary amine to
give compounds of the formula (I.3).
25. The process according to claim 24, where the leaving group Z is
a moiety selected from Br, Cl, tosyl, mesyl or triflyl.
26. A molding composition in accordance of claim 14 for producing
housings of electrical devices, computer housings, tooling, piping,
cables, hoses, wire sheathing, window profiles,
vehicle-construction components, tires, furniture, cushion foam and
mattress foam, tarpaulins, gaskets, composite foils, recording
disks, synthetic leather, packaging containers, adhesive-tape
foils, or coatings.
27. A molding composition in accordance with claim 14 for producing
moldings and foils that come in direct contact with people or with
foods.
28. The molding composition in accordance with claim 27, where the
moldings and foils are selected from medical products, hygiene
products, packaging for food or drink, products for the interior
sector, toys and child-care items, sports and leisure products,
apparel, or fibers for textiles.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to tetrahydrofuran
derivatives, to a plasticizer composition which comprises said
tetrahydrofuran derivatives, to molding compositions which comprise
a thermoplastic polymer and a tetrahydrofuran derivative of this
type, to a process for producing said tetrahydrofuran derivatives,
and to use of these.
PRIOR ART
[0002] Desired processing properties or desired performance
characteristics are achieved in many plastics by adding what are
known as plasticizers in order to render the plastics softer, more
flexible and/or more extensible. Plasticizers generally serve to
shift the thermoplastic region of plastics to lower temperatures,
so as to obtain the desired elastic properties at lower processing
temperatures and lower usage temperatures.
[0003] Production quantities of polyvinyl chloride (PVC) are among
the highest of any plastic. Because this material is versatile, it
is nowadays found in a wide variety of products used in everyday
life. PVC therefore has very great economic importance. PVC is
intrinsically a plastic that is hard and brittle up to about
80.degree. C., and is used in the form of rigid PVC (PVC-U) by
adding heat stabilizers and other additives. Flexible PVC (PVC-P)
is obtained only by adding suitable plasticizers, and can be used
for many applications for which rigid PVC is unsuitable.
[0004] Examples of other important thermoplastic polymers in which
plasticizers are usually used are polyvinyl butyral (PVB), homo-
and copolymers of styrene, polyacrylates, polysulfides, and
thermoplastic polyurethanes (PUs).
[0005] There are many different compounds marketed for plasticizing
PVC and other plastics. Phthalic diesters with alcohols of
different chemical structure have in the past often been used as
plasticizers because they have good compatibility with PVC and
advantageous performance characteristics, examples being
diethylhexyl phthalate (DEHP), diisononyl phthalate (DINP) and
diisodecyl phthalate (DIDP). Short-chain phthalates, e.g. dibutyl
phthalate (DBP), diisobutyl phthalate (DIBP), benzyl butyl
phthalate (BBP) or diisoheptyl phthalate (DIHP), are also used as
gelling aids ("fast fuser"), for example in the production of what
are known as plastisols. It is also possible to use dibenzoic
esters, such as dipropylene glycol dibenzoates, for the same
purpose alongside the short-chain phthalates. Phenyl esters of
alkylsulfonic acids are another class of plasticizers with good
gelling properties, and are marketed by way of example in the form
of mixtures as Mesamoll.RTM. TP-LXS 51067.
[0006] Plastisols initially are a suspension of finely pulverulant
plastics in liquid plasticizers. The solvation rate of the polymer
in the plasticizer here is very low at ambient temperature. The
polymer is noticeably solvated in the plasticizer only on heating
to relatively high temperatures. The individual isolated polymer
aggregates here swell and fuse to give a three-dimensional
high-viscosity gel. This procedure is termed gelling, and begins at
a certain minimum temperature which is termed gel point or
solvation temperature. The gelling step is not reversible.
[0007] Since plastisols take the form of liquids, these are very
often used for the coating of a very wide variety of materials,
e.g. textiles, glass nonwovens, etc. This coating is very often
composed of a plurality of sublayers.
[0008] In a procedure often used in the industrial processing of
plastisols, a layer of plastisol is therefore applied and then the
plastic, in particular PVC, with the plasticizer is subjected to
incipient gelling above the solvation temperature, thus producing a
solid layer composed of a mixture of gelled, partially gelled, and
ungelled polymer particles.
[0009] The next sublayer is then applied to this incipiently gelled
layer, and once the final layer has been applied the entire
structure is processed in its entirety to give the fully gelled
plastics product by heating to relatively high temperatures.
[0010] Another possibility, alongside production of plastisols, is
production of dry pulverulant mixtures of plasticizer and polymers.
These dry blends, in particular based on PVC, can then be further
processed at elevated temperatures for example by extrusion to give
pellets, or processed through conventional shaping processes, such
as injection molding, extrusion, or calendering, to give the fully
gelled plastics product.
[0011] In particular in the production and processing of PVC
plastisols, for example for producing PVC coatings, it is inter
alia desirable to have available, as gelling aid, a plasticizer
with minimal gelling point and low viscosity. High storage
stability of the plastisol is moreover also desirable, i.e. the
ungelled plastisol is intended to exhibit no, or only a slight,
viscosity rise over the course of time at ambient temperature. As
far as possible, these properties are intended to be achieved by
addition of a suitable plasticizer with rapid-gelling properties,
with no need for the use of other viscosity-reducing additives
and/or of solvents.
[0012] Another known method for establishing the desired properties
is to use mixtures of plasticizers, e.g. to use at least one
plasticizer which provides good thermoplastic properties but has
poor gelling effect, in combination with at least one gelling
aid.
[0013] There is a need to replace the phthalate plasticizers
mentioned in the introduction, because these are not entirely free
from toxicological concerns. This specifically applies to sensitive
application sectors such as toys, food packaging, or medical
items.
[0014] Various alternate plasticizers for a variety of plastics,
and specifically for PVC, are known in the prior art.
[0015] A plasticizer class that is known from the prior art and
that can be used as alternative to phthalates is based on the
cyclohexanepolycarboxylic acids described in WO 99/32427. Unlike
their unhydrogenated aromatic analogs, these compounds give rise to
no toxicological concerns, and can be used even in sensitive
application sectors. The corresponding lower alkyl esters generally
have rapid-gelling properties.
[0016] WO 00/78704 describes selected dialkylcyclohexane-1,3- and
1,4-dicarboxylic esters for the use as plasticizer in synthetic
materials.
[0017] U.S. Pat. No. 7,973,194 B1 teaches the use of dibenzyl
cyclohexane-1,4-dicarboxylate, benzyl butyl
cyclohexane-1,4-dicarboxylate, and dibutyl
cyclohexane-1,4-dicarboxylate as rapid-gelling plasticizers for
PVC.
[0018] Some diether derivatives of
2,5-di(hydroxymethyl)tetrahydrofuran are already known materials.
WO 2009/141166 describes a fuel composition composed of
ring-hydrogenated alkylfurfuryl ethers of the general formula:
R''-TF-CH.sub.2--O--R, in which IF is a 2,5-disubstituted
tetrahydrofuran ring, R is a hydrocarbyl group having from 1 to 20
carbon atoms, R'' represents a methyl group, a hydroxymethyl group,
or else the product of an aldol condensation, or represents an
alkoxymethyl group of the general formula: --CH.sub.2--O--R', in
which R' is a hydrocarbyl group having from 1 to 20 carbon atoms.
Only methyl and ethyl are specifically used as moiety R and R'.
Said document claims that these compounds are novel materials, and
also describes a process for producing these, but teaches only use
of these as fuel or fuel additives, rather than as plasticizer.
[0019] The esters of 2,5-furandicarboxylic acid (FDCA) are another
plasticizer class.
[0020] WO 2012/113608 describes C.sub.5-dialkyl esters of
2,5-furandicarboxylic acid and use of these as plasticizers. These
short-chain esters are specifically also suitable for producing
plastisols.
[0021] WO 2012/113609 describes C.sub.7-dialkyl esters of
2,5-furandicarboxylic acid and use of these as plasticizers.
[0022] WO 2011/023490 describes C.sub.9-dialkyl esters of
2,5-furandicarboxylic acid and use of these as plasticizers.
[0023] WO 2011/023491 describes C.sub.10-dialkyl esters of
2,5-furandicarboxylic acid and use of these as plasticizers.
[0024] R. D. Sanderson et al. (J. Appl. Pol. Sci., 1994, vol. 53,
1785-1793) describe the synthesis of esters of
2,5-furandicarboxylic acid and use of these as plasticizers for
plastics, in particular polyvinyl chloride (PVC), polyvinyl butyral
(PVB), polylactic acid (PLA), polyhydroxybutyric acid (PHB) or
polyalkyl methacrylate (PAMA). Specifically, the di(2-ethylhexyl),
di(2-octyl), dihexyl, and dibutyl esters of 2,5-furandicarboxylic
acid are described, and the plasticizing properties of these are
characterized by way of dynamic mechanical thermal analyses.
[0025] U.S. Pat. No. 3,259,636 describes a process for producing
esters of cis-2,5-tetrahydrofurandicarboxylic acid, where hydrogen,
2,5-furandicarboxylic acid and an alcohol are reacted in the
presence of a noble metal catalyst in a one-pot reaction. It is
moreover disclosed that the esters of alcohols having 6 or more
carbon atoms are suitable as plasticizers in resin
compositions.
[0026] It is an object of the present invention to provide novel
compounds which can advantageously be used as, or in, plasticizers
for thermoplastic polymers and elastomers. They are intended to be
free from toxicological concerns and to be capable of production
from readily obtainable starting materials which preferably at
least to some extent derive from renewable raw materials. They are
intended to have good gelling properties and/or to exhibit low
viscosity in the ungelled state, and therefore to be particularly
suitable for providing plastisols. The novel compounds are
accordingly intended to be able to at least equally replace the
standard petrochemically based plasticizers that are mainly used
nowadays.
[0027] Surprisingly, said object is achieved via tetrahydrofuran
derivatives of the general formula (I)
##STR00001##
in which X is *--(C.dbd.O)--O--, *--(CH.sub.2).sub.n--O-- or
*--(CH.sub.2).sub.n--O--(C.dbd.O)--, where is the point of linkage
to the tetrahydrofuran ring, and n has the value 0, 1, or 2; and
R.sup.1 and R.sup.2 are selected mutually independently from
C.sub.4-C.sub.5-alkyl and C.sub.5-C.sub.6-cycloalkyl, where the
cycloalkyl moieties are unsubstituted or can have substitution by
at least one C.sub.1-C.sub.10-alkyl moiety.
[0028] The invention further provides plasticizer compositions
which comprise at least one compound of the general formula (I) as
defined above and hereinafter, and at least one plasticizer
different from the compounds of the formula (I).
[0029] The invention further provides processes for producing
compounds of the general formula (I).
[0030] The invention further provides the use of compounds of the
general formula (I) as, or in, plasticizers for thermoplastic
polymers, in particular polyvinyl chloride (PVC).
[0031] The invention further provides molding compositions which
comprise at least one thermoplastic polymer and at least one
compound of the general formula (I) as defined above and
hereinafter.
[0032] The invention further provides the use of said molding
compositions for producing moldings and foils.
DESCRIPTION OF THE INVENTION
[0033] The compounds (I) of the invention exhibit the following
advantages: [0034] By virtue of their physical properties, the
compounds (I) of the invention have very good suitability for
applications as plasticizers or as component of a plasticizer
composition for thermoplastic polymers, in particular for PVC.
[0035] By virtue of their low solvation temperatures in accordance
with DIN 53408, the compounds (I) of the invention have very good
suitability as gelling aids. They are therefore suitable for
reducing the temperature required for gelling of a thermoplastic
polymer and/or for increasing the gelling rate. [0036] The
compounds of the general formula (I) of the invention feature very
good compatibility with a wide variety of different plasticizers.
They are specifically suitable in combination with conventional
plasticizers for improving gelling performance. [0037] The
compounds (I) of the invention are advantageously suitable for
producing plastisols. [0038] The compounds (I) of the invention are
suitable for the use for producing moldings and foils for sensitive
application sectors, for example medical products, food packaging,
products for the interior sector, for example in dwellings and in
vehicles, and for toys, child-care items, etc. [0039] The compounds
(I) of the invention can be produced by using readily obtainable
starting materials. A particular economic and environmental
advantage of the present invention derives from the possibility of
using, in the production of the compounds (I) of the invention, not
only petrochemical raw materials that are available in large
quantities but also renewable raw materials. By way of example,
therefore, it is possible to obtain the starting materials for the
furan rings from naturally occurring carbohydrates, such as
cellulose and starch, while the alcohols that can be used for
introducing the side chains are available from large-scale
industrial processes. It is thus possible on the one hand to comply
with the "sustainable" materials requirement while on the other
hand also permitting cost-effective production. [0040] The
processes for producing the compounds (I) of the invention are
simple and efficient, and these can therefore be provided without
difficulty on a large industrial scale.
[0041] As previously mentioned, it has surprisingly been found that
the compounds of the general formula (I), in particular the
C.sub.4-C.sub.5-dialkyl esters of tetrahydrofurandicarboxylic acid,
have very low solvation temperatures, and also excellent gelling
properties in the production of plastisols, in particular of PVC
plastisols: their solvation temperatures are markedly below the
solvation temperatures of the corresponding dialkyl esters of
2,5-furandicarboxylic acid or phthalic acid, and have at least
equivalent rapid-gelling properties. This was not to be expected,
since by way of example ring-hydrogenated phthalates such as
diisononyl cyclohexane-1,2-dicarboxylate generally have higher
solvation temperatures than their unhydrogenated forms: by way of
example, the solvation temperature of diisononyl
1,2-cyclohexanedicarboxylate is higher at 151.degree. C. than that
of diisononyl phthalate at 132.degree. C., in accordance with DIN
53408.
[0042] For the purposes of the present invention, the expression
gelling aid means a plasticizer which has a solvation temperature
below 120.degree. C. in accordance with DIN 53408. Gelling aids of
this type are in particular used for producing plastisols.
[0043] The compounds of the general formula (I.1) of the invention
can take the form either of pure cis-isomers or of pure
trans-isomers, or of cis/trans-isomer mixtures. The pure isomers
and the isomer mixtures of any desired composition are equally
suitable as plasticizers.
[0044] For the purposes of the present invention, the expression
"C.sub.1-C.sub.10-alkyl" comprises straight-chain or branched
C.sub.1-C.sub.10-alkyl groups. These preferably are straight-chain
or branched C.sub.1-C.sub.8-alkyl groups. Among these are methyl,
ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,
n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl,
1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl,
1-ethylpropyl, n-hexyl, 2-hexyl, 2-methylpentyl, 3-methylpentyl,
4-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,
2,3-dimethylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl,
3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,
1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, n-heptyl,
2-heptyl, 3-heptyl, 2-ethylpentyl, 1-propylbutyl, n-octyl, and the
like. These particularly preferably are straight-chain or branched
C.sub.1-C.sub.5-alkyl groups.
[0045] The expression "C.sub.4-C.sub.5-alkyl" comprises
straight-chain and branched C.sub.4-C.sub.5-alkyl groups. It is
preferable that C.sub.4-C.sub.5-alkyl is selected from n-butyl,
isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 2-methylbutyl,
3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl,
2,2-dimethylpropyl, and 1-ethylpropyl. It is particularly
preferable that C.sub.4-C.sub.5-alkyl is n-butyl, isobutyl, or
n-pentyl.
[0046] The expression "C.sub.5-C.sub.6-cycloalkyl" comprises for
the purposes of the present invention cyclic hydrocarbons having
from 5 to 6, in particular having 6, carbon atoms. Among these are
cyclopentyl and cyclohexyl.
[0047] Substituted C.sub.5-C.sub.6-cycloalkyl groups can, as
permitted by their ring size, have one or more (e.g. 1, 2, 3, 4, or
5) C.sub.1-C.sub.10-alkyl substituents. Examples of
C.sub.5-C.sub.6-cycloalkyl groups are 2- and 3-methylcyclopentyl
2-, and 3-ethylcyclopentyl, 2-, 3-, and 4-methyl-cyclohexyl, 2-,
3-, and 4-ethylcyclohexyl, 2-, 3-, and 4-Propylcyclohexyl, 2-, 3-,
and 4-isopropylcyclohexyl, 2-, 3-, and 4-butylcyclohexyl, 2-, 3-,
and 4-sec-butylcyclohexyl, and 2-, 3-, and
4-tert-butylcyclohexyl.
[0048] It is preferable that the definitions of the groups X in the
compounds of the general formula (I) are identical.
[0049] In a first preferred embodiment, both of the groups X in the
compounds of the general formula (I) are *--(C.dbd.O)--O--.
[0050] In another preferred embodiment, both of the groups X in the
compounds of the general formula (I) are
*--(CH.sub.2)--O--(C.dbd.O)--.
[0051] In another preferred embodiment, both of the groups X in the
compounds of the general formula (I) are *--(CH.sub.2).sub.n--O--,
where n is 0, 1 or 2. It is particularly preferable that n is
2.
[0052] It is preferable that the moieties R.sup.1 and R.sup.2 in
the compounds of the general formula (I) are mutually independently
an unbranched or branched C.sub.4-alkyl moiety.
[0053] It is particularly preferable that the moieties R.sup.1 and
R.sup.2 in the compounds of the general formula (I) are mutually
independently n-butyl or isobutyl.
[0054] In a preferred embodiment, the definitions of the moieties
R.sup.1 and R.sup.2 in the compounds of the general formula (I) are
identical.
[0055] Preferred compounds of the general formula (I) are those
selected from [0056] di(n-butyl) 2,5-tetrahydrofurandicarboxylate,
[0057] di-n-butyl ether of 2,5-di(hydroxymethyl)tetrahydrofuran,
[0058] 2,5-di(hydroxymethyl)tetrahydrofuran di-n-butanoate, [0059]
di(isobutyl) 2,5-tetrahydrofurandicarboxylate, [0060] diisobutyl
ether of 2,5-di(hydroxymethyl)tetrahydrofuran, [0061]
2,5-di(hydroxymethyl)tetrahydrofuran diisobutanoate, and also
mixtures of 2 or more of the abovementioned compounds.
[0062] A particularly preferred compound of the general formula (I)
is di(n-butyl) 2,5-tetrahydrofurandicarboxylate.
[0063] Production of the Compounds of the General Formula (I)
[0064] Production of the diesters of
2,5-tetrahydrofurandicarboxylic acid
[0065] The invention further provides a process for producing
compounds of the general formula (I.1),
##STR00002##
in which [0066] R.sup.1 and R.sup.2 are selected mutually
independently from C.sub.4-C.sub.5-alkyl and
C.sub.5-C.sub.6-cycloalkyl, where the cycloalkyl moieties are
unsubstituted or can have substitution by at least one
C.sub.1-C.sub.10-alkyl moiety, where [0067] a) optionally
2,5-furandicarboxylic acid or an anhydride or acyl halide thereof
is reacted with a C.sub.1-C.sub.3-alkanol in the presence of a
catalyst to give a di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate, [0068] b1) 2,5-furandicarboxylic acid or an
anhydride or acyl halide thereof, or the di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate obtained in step a), is reacted with at
least one alcohol R.sup.1--OH and, if R.sup.1 and R.sup.2 are
different, also with at least one alcohol R.sup.2--OH, in the
presence of at least one catalyst to give a compound of the formula
(I.1a),
[0068] ##STR00003## [0069] c1) the compound (I.1a) obtained in step
b1) is hydrogenated with hydrogen in the presence of at least one
hydrogenation catalyst to give the compound of the general formula
(I.1), or [0070] b2) 2,5-furandicarboxylic acid or the
di(C.sub.1-C.sub.3-alkyl) 2,5-furandicarboxylate obtained in step
a) is hydrogenated with hydrogen in the presence of at least one
hydrogenation catalyst to give a compound of the general formula
(I.1 b),
[0070] ##STR00004## [0071] the compound (I, 1b) obtained in step
b2) is reacted with at least one alcohol R.sup.1--OH and, if
R.sup.1 and R.sup.2 are different, also with at least one alcohol
R.sup.2--OH, in the presence of a catalyst to give a compound of
the formula (I.1).
[0072] In respect of suitable and preferred embodiments of the
moieties R.sup.1 and R.sup.2, reference is made to the entirety of
the information provided above.
[0073] The process of the invention permits the production of the
2,5-tetrahydrofurandicarboxylic esters of the general formula (I.1)
by two different routes (hereinafter termed variant 1 and variant
2).
[0074] Examples of C.sub.1-C.sub.3-alkanols suitable for use in
step a) are methanol, ethanol, n-propanol, and mixtures
thereof.
[0075] In variant 1 of the process of the invention, the
2,5-furandicarboxylic acid or the di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylate obtained in step a) is subjected to
esterification or transesterification with at least one alcohol
R.sup.1--OH and, if R.sup.1 and R.sup.2 are different, also with at
least one alcohol R.sup.2--OH, to give the compounds of the formula
(I.1a), which are then hydrogenated to give compounds of the
general formula (I.1) (step c1)).
[0076] In variant 2, the 2,5-furandicarboxylic acid or the
2,5-di(C.sub.1-C.sub.3-alkyl) furandicarboxylate obtained in step
a) is first hydrogenated to give 2,5-tetrahydrofurandicarboxylic
acid or, respectively, a compound of the general formula (I.1 b)
(step b2)), and the hydrogenation product is then reacted with at
least one alcohol R.sup.1--OH and, if R.sup.1 and R.sup.2 are
different, also with at least one alcohol R.sup.2--OH to give the
compounds of the general formula (I.1) (step c2)).
[0077] Esterification
[0078] Conventional processes known to the person skilled in the
art can be used to convert the 2,5-furandicarboxylic acid (FDCA) or
the 2,5-tetrahydrofurandicarboxylic acid to the corresponding ester
compounds of the general formulae (I.1), (I.1a), and (I.1b). Among
these are the reaction of at least one alcohol component selected
from C.sub.1-C.sub.3-alkanols or from the alcohols R.sup.1--OH and,
respectively. R.sup.2--OH with FDCA or a suitable derivative
thereof. Examples of suitable derivatives are the acyl halides and
anhydrides. A preferred acyl halide is the acyl chloride.
Esterification catalysts that can be used are the catalysts
conventionally used for this purpose, e.g. mineral acids, such as
sulfuric acid and phosphoric acid; organic sulfonic acids, such as
methanesulfonic acid and p-toluenesulfonic acid; amphoteric
catalysts, in particular titanium compounds, tin(IV) compounds, or
zirconium compounds, e.g. tetraalkoxytitanium compounds, e.g.
tetrabutoxytitanium, and tin(IV) oxide. The water produced during
the reaction can be removed by conventional measures, e.g. by
distillation. WO 02/038531 describes a process for producing esters
where a) a mixture consisting essentially of the acid component or
an anhydride thereof and of the alcohol component is heated to
boiling point in the presence of an esterification catalyst in a
reaction zone, b) the vapors comprising alcohol and water are
fractionated to give an alcohol-rich fraction and a water-rich
fraction, c) the alcohol-rich fraction is returned to the reaction
zone, and the water-rich fraction is discharged from the process.
Esterification catalysts used are the abovementioned catalysts. An
effective amount of the esterification catalyst is used and is
usually in the range from 0.05 to 10% by weight, preferably from
0.1 to 5% by weight, based on the entirety of acid component (or
anhydride) and alcohol component. Other detailed descriptions of
the conduct of esterification processes are found by way of example
in U.S. Pat. No. 6,310,235, U.S. Pat. No. 5,324,853, DE-A 2612355
(Derwent Abstract No. DW 77-72638 Y) or DE-A 1945359 (Derwent
Abstract No. DW 73-27151 U). The entirety of the documents
mentioned is incorporated herein by way of reference.
[0079] In one preferred embodiment, the esterification of FDCA or
of the 2,5-tetrahydrofurandicarboxylic acid is carried out in the
presence of the alcohol components described above by means of an
organic acid or mineral acid, in particular concentrated sulfuric
acid. The amount used of the alcohol component here is
advantageously at least twice the stochiometric amount, based on
the FDCA or the 2,5-tetrahydrofurandicarboxylic acid or a
derivative.
[0080] The esterification can generally take place at ambient
pressure or at reduced or elevated pressure. It is preferable that
the esterification is carried out at ambient pressure or reduced
pressure.
[0081] The esterification can be carried out in the absence of any
added solvent or in the presence of an organic solvent.
[0082] If the esterification is carried out in the presence of a
solvent, it is preferably an organic solvent that is inert under
the reaction conditions. Among these are by way of example
aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, and
aromatic and substituted aromatic hydrocarbons and ethers. It is
preferable that the solvent is one selected from pentane, hexane,
heptane, ligroin, petrol ether, cyclohexane, dichloromethane,
trichloromethane, tetrachloromethane, benzene, toluene, xylene,
chlorobenzene, dichlorobenzenes, dibutyl ether, THF, dioxane, and
mixtures thereof.
[0083] The esterification is usually carried out in the temperature
range from 50 to 250.degree. C.
[0084] If the esterification catalyst is selected from organic
acids or mineral acids, the esterification is carried out typically
in a temperature range from 50 to 160.degree. C.
[0085] If the esterification catalyst is selected from amphoteric
catalysts, the esterification is carried out typically in a
temperature range from 100 to 250.degree. C.
[0086] The esterification can take place in the absence of or in
the presence of an inert gas. The expression inert gas generally
means a gas which under the prevailing reaction conditions does not
enter into any reactions with the starting materials, reagents, or
solvents participating in the reaction, or with the resultant
products. It is preferable that the esterification takes place
without addition of any inert gas.
[0087] Transesterification:
[0088] Conventional processes known to the person skilled in the
art can be used for the reaction, described in steps b1) and c2),
of the di(C.sub.1-C.sub.3-alkyl) 2,5-furandicarboxylates and,
respectively, the di(C.sub.1-C.sub.3-alkyl)
2,5-tetrahydrofurandicarboxylates to give the corresponding ester
compounds I.1a and, respectively, I.1. Among these are the reaction
of the di(C.sub.1-C.sub.3)-alkyl esters with at least one
C.sub.4-C.sub.5-alkanol or C.sub.5-C.sub.6-cycloalkanol or a
mixture thereof in the presence of a suitable transesterification
catalyst.
[0089] Transesterification catalysts that can be used are the
conventional catalysts usually used for transesterification
reactions, where these are mostly also used in esterification
reactions. Among these are by way of example mineral acids, such as
sulfuric acid and phosphoric acid; organic sulfonic acids, such as
methanesulfonic acid and p-toluenesulfonic acid; and specific metal
catalysts from the group of the tin(IV) catalysts, for example
dialkyltin dicarboxylates, such as dibutyltin diacetate,
trialkyltin alkoxides, monoalkyltin compounds, such as monobutyltin
dioxide, tin salts, such as tin acetate, or tin oxides; from the
group of the titanium catalysts: monomeric and polymeric titanates
and titanium chelates, for example tetraethyl orthotitanate,
tetrapropyl orthotitanate, tetrabutyl orthotitanate,
triethanolamine titanate; from the group of the zirconium
catalysts: zirconates and zirconium chelates, for example
tetrapropyl zirconate, tetrabutyl zirconate, triethanolamine
zirconate; and also lithium catalysts, such as lithium salts,
lithium alkoxides; and aluminum(III) acetylacetonate, chromium(III)
acetylacetonate, iron(III) acetylacetonate, cobalt(II)
acetylacetonate, nickel(II) acetylacetonate, and zinc(II)
acetylacetonate.
[0090] The amount of transesterification catalyst used is from
0.001 to 10% by weight, preferably from 0.05 to 5% by weight. The
reaction mixture is preferably heated to the boiling point of the
reaction mixture, the reaction temperature therefore being from
20.degree. C. to 200.degree. C., depending on the reactants.
[0091] The transesterification can take place at ambient pressure
or at reduced or elevated pressure. It is preferable that the
transesterification is carried out at a pressure of from 0.001 to
200 bar, particularly from 0.01 to 5 bar. The relatively
low-boiling-point alcohol eliminated during the transesterification
is preferably continuously removed by distillation in order to
shift the equilibrium of the transesterification reaction. The
distillation column necessary for this purpose generally has direct
connection to the transesterification reactor, and it is preferable
that said column is a direct attachment thereto. If a plurality of
transesterification reactors are used in series, each of said
reactors can have a distillation column, or the vaporized alcohol
mixture can preferably be introduced into a distillation column
from the final tanks of the transesterification reactor cascade by
way of one or more collection lines. The relatively
high-boiling-point alcohol reclaimed in said distillation is
preferably returned to the transesterification.
[0092] If an amphoteric catalyst is used, it is separated off
generally by hydrolysis and subsequent removal of the metal oxide
formed, by filtration, for example. Preferably, after reaction has
taken place, the catalyst is hydrolyzed by washing with water and
the precipitated metal oxide is removed by filtration. If desired,
the filtrate may be subjected to further work-up for the isolation
and/or purification of the product. The product is preferably
isolated by distillation.
[0093] In one preferred embodiment of steps 1b) and 2c), the
transesterification of the di(C.sub.1-C.sub.3-alkyl)
2,5-furandicarboxylates and, respectively,
di(C.sub.1-C.sub.3-alkyl) 2,5-tetrahydrofurandicarboxylates takes
place in the presence of the alcohol component and in the presence
of at least one titanium(IV) alcoholate. Preferred titanium(IV)
alcoholates are tetrapropoxytitanium, tetrabutoxytitanium, and
mixtures thereof. It is preferable that the amount used of the
alcohol component is at least twice the stochiometric amount, based
on the di(C.sub.1-C.sub.3-alkyl) ester used.
[0094] The transesterification can be carried out in the absence
of, or in the presence of, an added organic solvent. It is
preferable that the transesterification is carried out in the
presence of an inert organic solvent. Suitable organic solvents are
those mentioned above for the esterification. Among these are
specifically toluene and THF.
[0095] The transesterification is preferably carried out in the
temperature range from 50 to 200.degree. C.
[0096] The transesterification can take place in the absence of or
in the presence of an inert gas. The expression inert gas generally
means a gas which under the prevailing reaction conditions does not
enter into any reactions with the starting materials, reagents, or
solvents participating in the reaction, or with the resultant
products. It is preferable that the transesterification takes place
without addition of any inert gas.
[0097] Hydrogenation
[0098] Many processes and catalysts for the hydrogenation of the
double bonds of the furan ring carried out in steps c1) and b2) of
the invention are available to the person skilled in the art and
these by way of example are also used in the hydrogenation of
esters of aromatic polycarboxylic acids, examples being phthalates,
isophthalates and terephthalates. By way of example, the
ring-hydrogenation process described in WO 99/032427 is suitable.
This comprises hydrogenation at from 50 to 250.degree. C. and at a
pressure of from 20 to 300 bar by means of catalysts which comprise
at least one metal of transition group VIII of the Periodic Table
of the Elements, for example platinum, rhodium, palladium, cobalt,
nickel, or ruthenium, preferably ruthenium, either alone or
together with at least one metal from transition group I or VII of
the Periodic Table of the Elements, for example copper or
ruthenium, deposited on a mesoporous aluminum oxide support
material with bimodal pore distribution. The ring-hydrogenation
process described in WO 02/100536 is moreover suitable. This
comprises hydrogenation with use of a ruthenium catalyst on
amorphous silicon dioxide as support. Other suitable processes are
described in the following documents: EP-A 1266882--Use of a
nickel/magnesium oxide on kieselguhr catalyst, WO 03/029181--Use of
a nickel/zinc on silicon dioxide catalyst, WO 03/029168--Use of a
palladium/ZnO on Al.sub.2O.sub.3 catalyst and of a ruthenium/ZnO on
.alpha.-Al.sub.2O.sub.3 catalyst, or WO 04/09526--Use of a
ruthenium on titanium dioxide catalyst. Other suitable catalysts
are likewise Raney catalysts, preferably Raney nickel. Other
suitable support materials alongside those already mentioned are by
way of example zirconium dioxide (ZrO.sub.2), sulfated zirconium
dioxide, tungsten carbide (WC), titanium dioxide (TiO.sub.2),
sulfated carbon, activated charcoal, aluminum phosphate,
aluminosilicates, or phosphated aluminum oxide, or else a
combination thereof.
[0099] The hydrogenation can take place by analogy with the known
hydrogenation processes for hydrogenating organic compounds which
have hydrogenatable groups. To this end, the organic compound in
the form of liquid phase or gas phase, preferably in the form of
liquid phase, is brought into contact with the catalyst in the
presence of hydrogen. The liquid phase can by way of example be
passed over a fluidized bed of catalyst (fluidized bed method) or
can be passed over a fixed bed of catalyst (fixed bed method).
[0100] In the process of the invention, is preferable that the
hydrogenation takes place in a fixed-bed reactor.
[0101] The hydrogenation can be designed to take place either
continuously or else batchwise, preference being given here to the
continuous design of the process. The batchwise hydrogenation can
use a reaction apparatus conventionally used for this purpose, e.g.
a stirred reactor. It is preferable that the hydrogenation of the
invention is carried out continuously in fixed-bed reactors in the
bottoms method or trickle-bed method. The hydrogen here can be
passed over the catalyst cocurrently with the solution of the
starting material to be hydrogenated, or else in
countercurrent.
[0102] Suitable apparatuses for conducting fluidized-bed-catalyst
hydrogenation and fixed-bed-catalyst hydrogenation are known in the
prior art, e.g. from Ullmanns Enzyklopadie der Technischen Chemie
[Ullmann's Encyclopedia of Industrial Chemistry], 4.sup.th edition,
volume 13, pp. 135 ff., and also from P. N. Rylander,
"Hydrogenation and Dehydrogenation" in Ullmann's Encyclopedia of
Industrial Chemistry, 5th edn. on CD-ROM.
[0103] The hydrogenation generally takes place under elevated
hydrogen pressure. Preference is given to hydrogen pressure in the
range from 2 to 500 bar, particularly from 10 to 300 bar.
[0104] It is preferable that the hydrogenation takes place in the
presence of an organic solvent that is inert under the
hydrogenation conditions. Suitable solvents are those previously
defined for the esterification. Specifically, an ether is used, for
example THF, or a dialkylene glycol, or a mono- or diether thereof,
for example glyme.
[0105] The hydrogenation is carried out at a temperature in the
range from 20 to 350.degree. C., particularly preferably from 50 to
300.degree. C.
[0106] The amount of hydrogen used for the hydrogenation is
generally from 1 to 15 times the stochiometric amount of hydrogen
theoretically needed for the complete hydrogenation of the furan
ring.
[0107] In one preferred embodiment of steps c1) and b2), the
hydrogenation of the furan ring is carried out with platinum,
rhodium, palladium, cobalt, nickel, or ruthenium, in particular
platinum and palladium, deposited on aluminum oxide, on zirconium
dioxide, on sulfated zirconium dioxide, on zinc oxide, or on
silicon dioxide, in particular on zirconium dioxide, in the
presence of an inert solvent, under hydrogen pressure of from 150
to 300 bar, at a temperature of from 150 to 250.degree. C.
[0108] The hydrogenation processes described can give preference to
formation of the cis- or trans-isomer of the
2,5-tetrahydrofurandicarboxylic esters in accordance with the
selected hydrogenation conditions, for example catalyst
composition, or hydrogenation temperature: it is possible to
produce cis- or trans-2,5-tetrahydrofurandicarboxylic esters that
are in essence isomerically pure, or else a mixture with various
proportions of cis- and trans-isomers. The expression "in essence
isomerically pure" here means content of at least 95% by weight of
a particular isomer, based on the total weight of the
2,5-tetrahydrofurandicarboxylic ester.
[0109] The compounds of the general formula (I.1) of the invention
can accordingly take the form of pure cis-isomers or take the form
of pure trans-isomers, or take the form of cis/trans-isomer
mixtures. The pure isomers and the isomer mixtures of any desired
composition are equally suitable as plasticizers.
[0110] In one particularly preferred embodiment of steps c1) and
b2), FDCA and, respectively, the esters of the
2,5-furandicarboxylic acid from steps a) and b1) are dissolved in
an inert solvent and fully hydrogenated in the presence of a
heterogeneous Pd/Pt catalyst at a hydrogen pressure of from 50 to
300 bar and at from 100 to 250.degree. C. The hydrogenation here
preferably takes place continuously by the fixed-bed method, where
the hydrogen is conducted in countercurrent over the catalyst. In
this embodiment, it is preferable to use THF as solvent. In this
embodiment it is moreover preferable to use a Pd/Pt catalyst on
ZrO.sub.2. The preferred reaction temperature for this embodiment
is in the range from 100 to 200.degree. C. In this embodiment, the
desired tetrahydrofuran derivatives are generally obtained with a
proportion of cis-isomer of at least 90% by weight, based on the
total amount of the cis/trans-isomers formed.
[0111] One particularly preferred embodiment of the process of the
invention comprises: [0112] a) reaction of 2,5-furandicarboxylic
acid with methanol in the presence of concentrated sulfuric acid to
give the dimethyl 2,5-furandicarboxylate, [0113] 2b) hydrogenation
of the dimethyl 2,5-furandicarboxylate obtained in step a) with
hydrogen in the presence of a Pd/Pt catalyst on ZrO.sub.2 to give
the dimethyl 2,5-tetrahydrofurandicarboxylate, [0114] 2c) reaction
of the dimethyl 2,5-tetrahydrofurandicarboxylate obtained in step
2b) with at least one alcohol R.sup.1--OH in the presence of at
least one titanium(IV) alcoholate to give the compounds of the
general formula (I.1).
[0115] Production of the C.sub.4-C.sub.6-diether derivatives and,
respectively, C.sub.4-C.sub.6-diester derivatives of the formulae
(I.2) and, respectively, (I.3)
[0116] The invention further provides a process for producing
compounds of the general formula (I.2) or (I.3),
##STR00005##
in which R.sup.1 and R.sup.2 are selected mutually independently
from C.sub.4-C.sub.5-alkyl and C.sub.5-C.sub.6-cycloalkyl, where
the cycloalkyl moieties are unsubstituted or can have substitution
by at least one C.sub.1-C.sub.10-alkyl moiety, and n has the value
1 or 2, where [0117] for 2,5-di(hydroxymethyl)tetrahydrofuran (n=1)
or for 2,5-di(hydroxyethyl)tetrahydrofuran (n=2), reaction is
carried out with at least one alkylating reagent R.sup.1--Z and, if
R.sup.1 and R.sup.2 are different, also with at least one
alkylating reagent R.sup.2--Z, where Z is a leaving group, in the
presence of a base to give compounds of the formula (I.2), or
[0118] for 2,5-di(hydroxymethyl)tetrahydrofuran (n=1) or for
2,5-di(hydroxyethyl)tetrahydrofuran (n=2), reaction is carried out
with at least one acyl halide R.sup.1--(C.dbd.O)X and, if R.sup.1
and R.sup.2 are different, also with at least one acyl halide
R.sup.2--(C.dbd.O)X, where X is Br or Cl, in the presence of at
least one tertiary amine to give compounds of the formula
(I.3).
[0119] The alkylation is generally carried out in the presence of
an organic solvent that is inert under the reaction conditions.
Suitable solvents are those previously mentioned for the
estification. Aromatic hydrocarbons, such as toluene, are preferred
as solvent.
[0120] The leaving group Z is preferably a moiety selected from Br,
Cl, and the tosyl, mesyl, and triflyl group.
[0121] It is particularly preferable that the leaving group Z is
Br.
[0122] The alkylation reagents R.sup.1--Z and R.sup.2--Z are
commercially available or can be produced by way of suitable
reactions or procedures familiar to the person skilled in the art,
from the corresponding alcohols. By way of example, the alkyl
bromides R.sup.1--Br and, respectively, R.sup.2--Br preferably used
for this process can be produced in a known manner on a large
industrial scale from the appropriate alcohols R.sup.1--OH and,
respectively, R.sup.2--OH by using hydrogen bromide (HBr).
[0123] Suitable bases that can be used in the process of the
invention are mineral bases and/or strong organic bases. Among
these are by way of example inorganic bases or base-formers, for
example hydroxides, hydrides, amides, oxides, and carbonates of the
alkali metals and of the alkaline earth metals. Among these are
LiOH, NaOH, KOH, Mg(OH).sub.2, Ca(OH).sub.2, LiH, NaH, sodium amide
(NaNH.sub.2), diisopropylamide (LDA), Na.sub.2O, K.sub.2CO.sub.3,
Na.sub.2CO.sub.3 and Cs.sub.2CO.sub.3; and also organometallic
compounds, such as n-BuLi, or tert-BuLi. Preference is given to
NaOH, KOH, K.sub.2CO.sub.3, and Na.sub.2CO.sub.3.
[0124] The amount used here of the base is preferably at least a
two-fold stoichiometric excess, based on the
2,5-di(hydroxymethyl)tetrahydrofuran and, respectively,
2,5-di(hydroxyethyl)tetrahydrofuran. It is particularly preferable
to use an at least four-fold stoichiometric excess of base.
[0125] The alkylation can be carried out in the absence of, or in
the presence of, an organic solvent. The reaction is generally
carried out in the presence of an inert organic solvent, such as
pentane, hexane, heptane, ligroin, petroleum ether, cyclohexane,
dichloromethane, trichloromethane, tetrachloromethane, benzene,
toluene, xylene, chlorobenzene, dichlorobenzenes, dibutyl ether,
THF, dioxane, or a mixture thereof.
[0126] The alkylation can generally take place at ambient pressure,
reduced pressure, or elevated pressure. It is preferable that the
alkylation is carried out at ambient pressure.
[0127] It is preferable that the alkylation is carried out in the
temperature range from 30 to 200.degree. C., preferably from 50 to
150.degree. C.
[0128] The alkylation can take place in the absence of, or in the
presence of, an inert gas. It is preferable that the alkylation
uses no inert gas.
[0129] In one specific embodiment of the alkylation,
2,5-di(hydroxymethyl)tetrahydrofuran or
2,5-di(hydroxyethyl)tetrahydrofuran is converted to the diether
compounds of the general formula (I.2) in the presence of an at
least four-fold excess of base in an inert organic solvent and with
at least one alkyl bromide R.sup.1--Br and, respectively,
R.sup.2--Br. In relation to the moieties R.sup.1 and R.sup.2,
reference is made to the previous descriptions. As base, it is
preferable to use an alkali metal hydroxide, in particular KOH.
[0130] To produce the ester compounds of the general formula (I.3)
of the invention, it is preferable to react
2,5-di(hydroxymethyl)tetrahydrofuran or
2,5-di(hydroxyethyl)-tetrahydrofuran with at least one acyl halide
R.sup.1--(C.dbd.O)X and, if R.sup.1 and R.sup.2 are different, with
at least one acyl halide R.sup.2--(C.dbd.O)X, where X is Br or Cl,
in the presence of at least one tertiary amine, to give the
compounds of the formula (I.3).
[0131] There are also other familiar esterification methods,
alongside this process, available to the person skilled in the art,
as previously described in relation to the esterification of FDCA
and, respectively, 2,5-tetrahydrofurandicarboxylic acid.
[0132] The ester compounds of the general formula (I.3) can usually
be produced by using any of the tertiary amines familiar to the
person skilled in the art. Examples of suitable tertiary amines
are: [0133] from the group of the trialkylamines: trimethylamine,
triethylamine, tri-n-propylamine, diethylisopropylamine,
diisopropylethylamine and the like; [0134] from the group of the
N-cycloalkyl-N,N-dialkylamines: dimethylcyclohexylamine and
diethylcyclohexylamine; [0135] from the group of the
N,N-dialkylanilines: dimethylaniline and diethylaniline; [0136]
from the group of the pyridine and quinoline bases: pyridine,
.alpha.-, .beta.-, and .gamma.-picoline, and
4-(dimethylamino)pyridine (DMAP).
[0137] Preferred tertiary amines are trialkylamines and pyridine
bases, in particular triethylamine and 4-(dimethylamino)pyridine
(DMAP), and also mixtures thereof.
[0138] The esterification can take place at ambient pressure, or at
reduced or elevated pressure. It is preferable to carry out the
esterification at ambient pressure.
[0139] The esterification can be carried out in the absence of, or
in the presence of, an organic solvent. It is preferable to carry
out the esterification in the presence of an inert organic solvent,
as defined previously.
[0140] The esterification is usually carried out in the temperature
range from 50 to 200.degree. C.
[0141] The esterification can take place in the absence of, or in
the presence of, an inert gas.
[0142] In one preferred embodiment,
2,5-di(hydroxymethyl)tetrahydrofuran is reacted with an acyl
chloride R.sup.1--(C.dbd.O)Cl in the presence of triethylamine
and/or DAMP and of an inert organic solvent to give compounds of
the formula (I.3).
[0143] The preferred embodiments of the processes of the invention
for producing compounds of the general formula (I) use
C.sub.4-C.sub.5-alkanols, and also C.sub.5-C.sub.6-cycloalkanols,
as starting materials for the transesterification, esterification,
or alkylation.
[0144] Preferred C.sub.4-C.sub.5-alkanols can be straight-chain or
branched compounds, or can be composed of mixtures of
straight-chain and branched butanols and, respectively, pentanols.
Among these are 1-butanol 2-butanol, 2-methyl-1-propanol,
2-methyl-2-propanol, 1-pentanol, and 2-methylbutanol, and also
mixtures thereof. Preference is given to 1-butanol,
2-methyl-1-propanol, and 1-pentanol.
[0145] The C.sub.5-C.sub.6-cycloalkanols are those selected from
cyclopentanol and cyclohexanol, and mixtures thereof. Preference is
given to cyclohexanol.
[0146] Substituted C.sub.5-C.sub.6-cycloalkanols can, as permitted
by their ring size, have one or more (e.g. 1, 2, 3, 4, or 5)
C.sub.1-C.sub.10-alkyl substituents. Examples of
C.sub.5-C.sub.6-cycloalkanols are 2- and 3-methylcyclopentanol, 2-,
and 3-ethylcyclopentanol, 2-, 3-, and 4-methyl-cyclohexanol, 2-,
3-, and 4-ethylcyclohexanol, 2-, 3-, and 4-Propylcyclohexanol, 2-,
3-, and 4-isopropylcyclohexanol, 2-, 3-, and 4-butylcyclohexanol,
2-, 3-, and 4-sec-butylcyclohexanol, and 2-, 3-, and
4-tert-butylcyclohexanol.
[0147] The furan-2,5-dicarboxylic acid (FDCA, CAS No. 3238-40-2)
needed as starting material for the preferred processes for
producing compounds of the general formula (I) can either be
purchased commercially or can be produced by synthesis routes known
from the literature: possibilities for synthesis are found in the
publication by Lewkowski et al. published on the Internet with the
title "Synthesis, Chemistry and Application of
5-hydroxymethylfurfural and its derivatives" (Lewkowski et al.,
ARKIVOC 2001 (i), pp. 17-54, ISSN 1424-6376). A feature common to
most of these syntheses is acid-catalyzed reaction of
carbohydrates, particularly glucose and fructose, preferably
fructose, to give 5-hydroxymethylfurfural (5-HMF), which can be
separated from the reaction mixture by using technical processes
such as a two-phase method. Appropriate results have been described
by way of example by Leshkov et al in Science 2006, vol. 312, pp.
1933-1937, and by Zhang et al. in Angewandte Chemie 2008, vol. 120,
pp, 9485-9488. 5-HMF can then be oxidized to FDCA in a further
step, as cited by way of example by Christensen in ChemSusChem
2007, vol. 1, pp. 75-78.
[0148] 2,5-Bis(hydroxymethyl)tetrahydrofuran (CAS No. 104-80-3) can
likewise either be purchased or can be synthesized. The syntheses
described start from 5-HMF, which can be reduced in two steps by
way of 2,5-bis(hydroxymethyl)furan (2,5-BHF) or directly to give
2,5-di(hydroxymethyl)tetrahydrofuran (Lewkowski et al., ARKIVOC
2001 (i), pp. 17-54, ISSN 1424-6376).
[0149] 2,5-Bis(hydroxyethyl)tetrahydrofuran can be obtained via
reduction of methyl 2,5-furandiacetate. Methyl 2,5-furandiacetate
can be synthesized by way of suitable reactions familiar to the
person skilled in the art from 2,5-bis(hydroxymethyl)furan
(2,5-BHF), for example by analogy with the process described by Rau
et al. in Liebigs Ann. Chem., vol. 1984 (8, 1984), pp, 1504-1512.
ISSN 0947-3440. Here, 2,5-bis(chloromethyl)furan is prepared from
2-5-BHF via reaction with thionyl chloride, and is reacted via
exposure to KCN in benzene in the presence of [18]-crown-6 to give
2,5-bis(cyanomethyl)furan. 2,5-bis(cyanomethyl)furan can then be
hydrolyzed to give 2,5-furandiacetic acid and esterified with
methanol to give the dimethyl ester, or can be converted directly
to methyl 2,5-furandiacetate via alcoholysis with methanol (pinner
reaction). Methyl 2,5-furandiacetate can then either be first
hydrogenated to dimethyl tetrahydro-2,5-furandiacetate (by analogy
with steps b2) and, respectively, c1)) or can be reduced directly
to 2,5-bis(hydroxyethyl)tetrahydrofuran.
[0150] Methyl 2,5-furandiacetate can likewise be prepared by
analogy with the process described by Kern et al. in Liebigs Ann.
Chem., vol. 1985 (6. 1985), pp. 1168-1174, ISSN 0947-3440.
[0151] Plasticizer Composition
[0152] The compounds of the general formula (I) of the invention
feature very good compatibility with a wide variety of
plasticizers. They are specifically suitable in combination with
other plasticizers which have gelling properties that still require
improvement, in order to improve gelling performance: they permit
reduction of the temperature required for the gelling of a
thermoplastic polymer, and/or can increase the gelling rate of
plasticizer compositions.
[0153] If there are specific or complex requirements necessary for
an application, for example high low-temperature resilience, high
resistance to extraction or to migration, or very low plasticizer
volatility, it can be advantageous to use plasticizer compositions
for plasticizing thermoplastic polymers. This is true in particular
for flexible-PVC applications.
[0154] The invention therefore also provides plasticizer
compositions which comprise at least one compound of the general
formula (I) and at least one plasticizer different from the
compounds (I).
[0155] In relation to suitable and preferred compounds of the
general formula (I) for producing plasticizer compositions,
reference is made to the entirety of the suitable and preferred
compounds of the general formula (I) described previously. It is
preferable that the plasticizer compositions of the invention
comprise at least one compound of the general formula (I) in which
R.sup.1 and R.sup.2 are mutually independently unbranched or
branched C.sub.4-alkyl, in particular n-butyl or isobutyl. A
compound of the general formula (I) specifically suitable for
producing plasticizer compositions is di(n-butyl)
2,5-tetrahydrofurandicarboxylate.
[0156] It is preferable that the additional plasticizer different
from the compounds of the general formula (I) is one selected from
dialkyl phthalates, alkyl aralkyl phthalates, dialkyl
terephthalates, trialkyl trimellitates, dialkyl adipates, alkyl
benzoates, dibenzoic esters of glycols, hydroxybenzoic esters,
esters of saturated mono- and dicarboxylic acids, esters of
unsaturated dicarboxylic acids, amides and esters of aromatic
sulfonic acids, alkylsulfonic esters, glycerol esters, isosorbide
esters, phosphoric esters, citric triesters, alkylpyrrolidone
derivatives, 2,5-furandicarboxylic esters, epoxidized vegetable
oils based on triglycerides and saturated or unsaturated fatty
acids, polyesters derived from aliphatic and aromatic
polycarboxylic acids with polyhydric alcohols.
[0157] Preferred dialkyl phthalates have mutually independently
from 4 to 13 carbon atoms, preferably from 8 to 13 carbon atoms, in
the alkyl chains. An example of a preferred alkyl aralkyl phthalate
is benzyl butyl phthalate. It is preferable that the dialkyl
terephthalates have mutually independently in each case from 4 to
13 carbon atoms, in particular from 7 to 11 carbon atoms, in the
alkyl chains. Preferred dialkyl terephthalates are, for example,
di(n-butyl)terephthalic acid dialkyl esters,
di(2-ethylhexyl)terephthalic acid dialkyl esters,
di(isononyl)terephthalic acid dialkyl esters, or
di(2-propylheptyl)terephthalic acid dialkyl esters. It is
preferable that the trialkyl trimellitates have mutually
independently in each case from 4 to 13 carbon atoms, in particular
from 7 to 11 carbon atoms, in the alkyl chains. Preferably the
esters of saturated mono- and dicarboxylic acids are esters of
acetic acid, butyric acid, valeric acid, succinic acid, adipic
acid, sebacic acid, lactic acid, malic acid, or tartaric acid. It
is preferable that the dialkyl adipates have mutually independently
in each case from 4 to 13 carbon atoms, in particular from 6 to 10
carbon atoms, in the alkyl chains. Preferably the esters of
unsaturated dicarboxylic acids are esters of maleic acid and of
fumaric acid. It is preferable that the alkyl benzoates have
mutually independently in each case from 7 to 13 carbon atoms, in
particular from 9 to 13 carbon atoms, in the alkyl chains.
Preferred benzoic acid alkyl esters are, for example, isononyl
benzoate, isodecyl benzoate, or 2-propylheptyl benzoate. Preferred
dibenzoic esters of glycols are diethylene glycol dibenzoate and
dibutylene glycol dibenzoate. Preferred alkylsulfonic esters
preferably have an alkyl moiety having from 8 to 22 carbon atoms.
Among these are by way of example the phenyl and cresyl esters of
pentadecylsulfonic acid. Preferred isosorbide esters are isosorbide
diesters, preferably esterified mutually independently in each case
with C.sub.8-C.sub.13-carboxylic acids. Preferred phosphoric esters
are tri-2-ethylhexyl phosphate, trioctyl phosphate, triphenyl
phosphate, isodecyl diphenyl phosphate, bis(2-ethylhexyl)phenyl
phosphate, and 2-ethylhexyl diphenyl phosphate. The OH group in the
citric triesters can be present in free or carboxylated form,
preferably in acetylated form. It is preferable that the alkyl
moieties of the citric triesters have mutually independently from 4
to 8 carbon atoms, in particular from 6 to 8 carbon atoms.
Preference is given to alkylpyrrolidone derivatives having alkyl
moieties of from 4 to 18 carbon atoms. Preferred dialkyl
2,5-furandicarboxylates have mutually independently in each case
from 4 to 13 carbon atoms, preferably from 8 to 13 carbon atoms, in
the alkyl chains. The epoxidized vegetable oils are preferably, for
example, epoxidized fatty acids from epoxidized soybean oil,
available under the trade name reFlex.TM. from PolyOne, USA,
Preferably the polyesters derived from aliphatic and aromatic
polycarboxylic acids are polyesters of adipic acid with polyhydric
alcohols, in particular are dialkylene glycol polyadipates having
from 2 to 6 carbon atoms in the alkylene moiety.
[0158] In all of the abovementioned cases, the alkyl moieties can
in each case be linear or branched and in each case identical or
different. Reference is made to the general descriptions relating
to suitable and preferred alkyl moieties in the introduction.
[0159] In one particularly preferred embodiment, the plasticizer
compositions of the invention comprise at least one plasticizer
different from the compounds (I) and selected from dialkyl adipates
having from 4 to 9 carbon atoms in the side chain.
[0160] In another particularly preferred embodiment, the
plasticizer compositions of the invention comprise at least one
C.sub.5-C.sub.11-dialkyl ester of 2,5-furandicarboxylic acid.
Particular preference is given to the C.sub.7-C.sub.10-dialkyl
esters of 2,5-furandicarboxylic acid.
[0161] Suitable and preferred dialkyl esters of
2,5-furandicarboxylic acid are described in WO 2012/113608
(C.sub.5-dialkyl esters), WO 2012/113609 (C.sub.7-dialkyl esters),
WO 2011/023490 (C.sub.9-dialkyl esters), and WO 2011/023491
(C.sub.10-dialkyl esters). The dihexyl, di(2-ethylhexyl), and
di(2-octyl) esters of 2,5-furandicarboxylic acid and their
production are described by R. D. Sanderson et al. in J. Appl. Pol.
Sci., 1994, vol. 53, 1785-1793. The entire disclosure of those
documents is incorporated here by way of reference.
[0162] Particularly preferred dialkyl esters of
2,5-furandicarboxylic acid are the isomeric nonyl esters of
2,5-furandicarboxylic acid disclosed in WO 2011/023490. The
isomeric nonyl moieties here preferably derive from a mixture of
isomeric nonanols as described in WO 2011/023490, page 6, line 32
to page 10, line 15.
[0163] Molding Compositions
[0164] The present invention further provides a molding composition
comprising at least one thermoplastic polymer and at least one
compound of the general formula (I).
[0165] Thermoplastic polymers that can be used are any of the
thermoplastically processable polymers. In particular, these
thermoplastic polymers are those selected from: [0166] homo- and
copolymers which comprise at least one copolymerized monomer
selected from C.sub.2-C.sub.10-monoolefins, such as ethylene or
propylene, 1,3-butadiene, 2-chloro-1,3-butadiene, vinyl alcohol and
its C.sub.2-C.sub.10-alkyl esters, vinyl chloride, vinylidene
chloride, vinylidene fluoride, tetrafluoroethylene, glycidyl
acrylate, glycidyl methacrylate, acrylates and methacrylates with
alcohol components of branched and unbranched
C.sub.1-C.sub.10-alcohols, vinylaromatics, such as polystyrene,
(meth)acrylonitrile, .alpha.,.beta.-ethylenically unsaturated mono-
and dicarboxylic acids, and maleic anhydride; [0167] homo- and
copolymers of vinyl acetals; [0168] polyvinyl esters; [0169]
polycarbonates (PCs); [0170] polyesters, such as polyalkylene
terephthalates, polyhydroxyalkanoates (PHAs), polybutylene
succinates (PBSs), polybutylene succinate adipates (PBSAs); [0171]
polyethers; [0172] polyether ketones; [0173] thermoplastic
polyurethanes (TPUs); [0174] polysulfides; [0175] polysulfones; and
mixtures thereof.
[0176] Mention may be made by way of example of polyacrylates
having identical or different alcohol moieties from the group of
the C.sub.4-C.sub.6-alcohols, particularly of butanol, hexanol,
octanol, and 2-ethylhexanol, polymethyl methacrylate (PMMA), methyl
methacrylate-butyl acrylate copolymers,
acrylonitrile-butadiene-styrene copolymers (ABSs),
ethylene-propylene copolymers, ethylene-propylene-diene copolymers
(EPDMs), polystyrene (PS), styrene-acrylonitrile copolymers (SANs),
acrylonitrile-styrene-acrylate (ASA), styrene-butadiene-methyl
methacrylate copolymers (SBMMAs), styrene-maleic anhydride
copolymers, styrene-methacrylic acid copolymers (SMAs),
polyoxymethylene (POM), polyvinyl alcohol (PVAL), polyvinyl acetate
(PVA), polyvinyl butyral (PVB), polycaprolactone (PCL),
polyhydroxybutyric acid (PHB), polyhydroxyvaleric acid (PHV),
polylactic acid (PLA), ethylcellulose (EC), cellulose acetate (CA),
cellulose propionate (CP), and cellulose acetate/butyrate
(CAB).
[0177] Preferably the at least one thermoplastic polymer comprised
in the molding composition of the invention is polyvinyl chloride
(PVC), polyvinyl butyral (PVB), homo- and copolymers of vinyl
acetate, homo- and copolymers of styrene, polyacrylates,
thermoplastic polyurethanes (TPUs), or polysulfides.
[0178] The present invention further provides molding compositions
comprising at least one elastomer and at least one compound of the
general formula (I).
[0179] Preferably the elastomer comprised in the molding
compositions of the invention is at least one natural rubber (NR),
at least one rubber produced by a synthetic route, or a mixture
thereof. Examples of preferred rubbers produced by a synthetic
route are polyisoprene rubber (IR), styrene-butadiene rubber (SBR),
butadiene rubber (BR), nitrile-butadiene rubber (NBR), and
chloroprene rubber (CR).
[0180] Preference is given to rubbers or rubber mixtures which can
be vulcanized with sulfur.
[0181] For the purposes of the invention, the content (% by weight)
of elastomer in the molding compositions is from 20 to 99%,
preferably from 45 to 95%, particularly preferably from 50 to 90%,
and in particular from 55 to 85%.
[0182] The molding composition of the invention can comprise,
alongside at least one elastomer and at least one tetrahydrofuran
derivative of the general formula (I), at least one plasticizer
different from the compounds (I).
[0183] Suitable plasticizers different from the compounds (I) are
those of the type already defined above.
[0184] For the purposes of the invention, the molding compositions
which comprise at least one elastomer can comprise other suitable
additives, in addition to the above constituents. By way of
example, the materials may comprise reinforcing fillers, such as
carbon black or silicon dioxide, other fillers, a methylene donor,
such as hexamethylenetetraamine (HMT), a methylene acceptor, such
as phenolic resins modified with Cardanol (from cashew nuts), a
vulcanizing agent or crosslinking agent, a vulcanizing accelerator
or crosslinking accelerator, activators, various types of oil,
antioxidants, and other various additives which by way of example
can be mixed into tire compositions and into other rubber
compositions.
[0185] Specifically, the at least one thermoplastic polymer
comprised in the molding composition of the invention is polyvinyl
chloride (PVC).
[0186] Polyvinyl chloride is obtained via homopolymerization of
vinyl chloride. The polyvinyl chloride (PVC) used in the invention
can by way of example be produced via suspension polymerization,
microsuspension polymerization, emulsion polymerization, or bulk
polymerization. The production of PVC via polymerization of vinyl
chloride, and also the production and composition of plasticized
PVC, are described by way of example in "Becker/Braun,
Kunststoff-Handbuch" [Plastics Handbook], vol. 2/1:
Polyvinylchlorid [Polyvinyl chloride], 2nd edn., Carl Hanser
Verlag, Munich.
[0187] The K value, which characterizes the molar mass of the PVC,
and is determined in accordance with DIN 53726, is mostly from 57
to 90 for the PVC plasticized in the invention, preferably from 61
to 85, in particular from 64 to 75.
[0188] For the purposes of the invention, the content of PVC in the
mixtures is from 20 to 99% by weight, preferably from 45 to 95% by
weight, particularly preferably from 50 to 90% by weight, and in
particular from 55 to 85% by weight.
[0189] At least one plasticizer different from the compounds (I)
can be comprised in the molding composition of the invention,
alongside at least one thermoplastic polymer and at least one
tetrahydrofuran derivative of the general formula (0.
[0190] The proportion of the additional at least one plasticizer,
different from the compounds (I), in the molding composition of the
invention is from 10% to 90% by weight, preferably from 20% to 85%
by weight, and particularly preferably from 50% to 80% by weight,
based on the total amount of plasticizer present in the molding
composition.
[0191] Suitable plasticizers different from the compounds (I) are
those of the type already defined above.
[0192] It is particularly preferable that the at least one
additional plasticizer comprised in the molding composition of the
invention is selected from dialkyl adipates having from 4 to 9
carbon atoms in the side chain and 2,5-furandicarboxylic esters
having from 4 to 10 carbon atoms in the side chain, where the ester
groups can have either the same or a different number of carbon
atoms.
[0193] Amounts of plasticizer used differ in accordance with the
choice of thermoplastic polymer or thermoplastic polymer mixture
comprised in the molding composition. The total plasticizer content
in the molding composition is generally from 0.5 to 300 phr (parts
per 100 resins=parts by weight per 100 parts by weight of polymer),
preferably from 0.5 to 130 phr, particularly preferably from 1 to
35 phr.
[0194] Where the thermoplastic polymer in the molding compositions
of the invention is polyvinyl chloride and where the plasticizer
used comprises exclusively at least one of the
(C.sub.7-C.sub.12)-dialkyl esters of tetrahydrofurandicarboxylic
acid of the invention, the total plasticizer content in the molding
composition is from 5 to 300 phr, preferably from 10 to 100 phr,
and particularly preferably from 30 to 70 phr.
[0195] If the thermoplastic polymer in the molding compositions of
the invention is polyvinyl chloride, and if plasticizer mixtures
are used that comprise at least one compound of the general formula
(I) and at least one plasticizer different from the compounds (I),
the total plasticizer content in the molding composition is from 1
to 400 phr, preferably from 5 to 130 phr, particularly preferably
from 10 to 100 phr, and in particular from 15 to 85 phr.
[0196] If the polymer in the molding compositions of the invention
is rubbers, the total plasticizer content in the molding
composition is from 1 to 60 phr, preferably from 1 to 40 phr,
particularly preferably from 2 to 30 phr.
[0197] Molding Composition Additives
[0198] For the purposes of the invention, the molding compositions
comprising at least one thermoplastic polymer can comprise other
suitable additives. By way of example, the materials can comprise
stabilizers, lubricants, fillers, pigments, flame retardants, light
stabilizers, blowing agents, polymeric processing aids, impact
modifiers, optical brighteners, antistatic agents, or
biostabilizers.
[0199] Some suitable additives are described in more detail below.
However, the examples listed do not represent any restriction of
the molding compositions of the invention, but instead serve merely
for illustration. AU data relating to content are in % by weight,
based on the entire molding composition.
[0200] Stabilizers that can be used are any of the conventional PVC
stabilizers in solid and liquid form, for example conventional
Ca/Zn, Ba/Zn, Pb, or Sn stabilizers, and also acid-binding
phyllosilicates, such as hydrotalcite.
[0201] The molding compositions of the invention can have from 0.05
to 7% content of stabilizers, preferably from 0.1 to 5%,
particularly preferably from 0.2 to 4%, and in particular from 0.5
to 3%.
[0202] Lubricants are intended to be effective between the PVC
pastilles, and to counteract frictional forces during mixing,
plastification, and deformation.
[0203] The molding compositions of the invention can comprise, as
lubricants, any of the lubricants conventionally used for the
processing of plastics. Examples of those that can be used are
hydrocarbons, such as oils, paraffins, and PE waxes, fatty alcohols
having from 6 to 20 carbon atoms, ketones, carboxylic acids, such
as fatty acids and montanic acid, oxidized PE wax, metal salts of
carboxylic acids, carboxamides, and also carboxylic esters, for
example with the following alcohols: ethanol, fatty alcohols,
glycerol, ethanediol, and pentaerythritol, and with long-chain
carboxylic acids as acid component.
[0204] The molding compositions of the invention can have from 0.01
to 10% lubricant content, preferably from 0.05 to 5%, particularly
preferably from 0.1 to 3%, and in particular from 0.2 to 2%.
[0205] Fillers have an advantageous effect primarily on the
compressive strength, tensile strength, and flexural strength, and
also the hardness and heat resistance, of plasticized PVC.
[0206] For the purposes of the invention, the molding compositions
can also comprise fillers such as carbon black and other organic
fillers such as natural calcium carbonates, for example chalk,
limestone, and marble, dolomite, silicates, silica, sand,
diatomaceous earth, aluminum silicates, such as kaolin, mica, and
feldspat, and synthetic calcium carbonates. It is preferable to use
the following as fillers: calcium carbonates, chalk, dolomite,
kaolin, silicates, talc powder, or carbon black.
[0207] The molding compositions of the invention can have from 0.01
to 80% content of fillers, preferably from 0.1 to 60%, particularly
preferably from 0.5 to 50%, and in particular from 1 to 40%.
[0208] The molding compositions of the invention can also comprise
pigments in order to adapt the resultant product to be appropriate
to various possible uses.
[0209] For the purposes of the present invention, it is possible to
use either inorganic pigments or organic pigments. Examples of
inorganic pigments that can be used are cadmium pigments, such as
CdS, cobalt pigments, such as CoO/Al.sub.2O.sub.3, and chromium
pigments, such as Cr.sub.2O.sub.3. Examples of organic pigments
that can be used are monoazo pigments, condensed azo pigments,
azomethine pigments, anthraquinone pigments, quinacridones,
phthalocyanine pigments, dioxazine pigments, and aniline
pigments.
[0210] The molding compositions of the invention can have from 0.01
to 10% content of pigments, preferably from 0.05 to 5%,
particularly preferably from 0.1 to 3%, and in particular from 0.5
to 2%.
[0211] In order to reduce flammability and to reduce smoke
generation during combustion, the molding compositions of the
invention can also comprise flame retardants.
[0212] Examples of flame retardants that can be used are antimony
trioxide, phosphate esters, chloroparaffin, aluminum hydroxide,
boron compounds, molybdenum trioxide, ferrocene, calcium carbonate,
and magnesium carbonate.
[0213] The molding compositions of the invention can have from 0.01
to 10% content of flame retardants, preferably from 0.1 to 8%,
particularly preferably from 0.2 to 5%, and in particular from 0.5
to 2%.
[0214] The molding compositions can also comprise light stabilizers
in order to protect items produced from the molding compositions of
the invention from surface damage due to the effect of light.
[0215] For the purposes of the present invention it is possible by
way of example to use hydroxybenzophenones or
hydroxyphenylbenzotriazoles.
[0216] The molding compositions of the invention can have from 0.01
to 7% content of light stabilizers, preferably from 0.1 to 5%,
particularly preferably from 0.2 to 4%, and in particular from 0.5
to 3%.
[0217] Plastisol Applications
[0218] As described already, the good gelling properties of the
compounds of the invention make them particularly suitable for
producing plastisols.
[0219] Plastisols can be produced from various plastics. In one
preferred embodiment, the plastisols of the invention are a PVC
plastisol.
[0220] The plastisols of the invention may comprise not only at
least one plastic and at least one tetrahydrofuran derivative of
the general formula (I), but also, optionally, at least one
plasticizer different from the compounds (I).
[0221] The fraction of the additional at least one plasticizer,
different from the compounds (I), in the plastisol is from 10% to
90% by weight, preferably from 20% to 85% by weight, and
particularly preferably from 50% to 80% by weight, based on the
total amount of plasticizer present in the plastisol.
[0222] In the case of PVC plastisols comprising as plasticizers
exclusively at least one of the (C.sub.7-C.sub.12)-dialkyl esters
of tetrahydrofurandicarboxylic acid of the invention, the total
plasticizer fraction is customarily from 5 to 300 phr, preferably
from 10 to 100 phr.
[0223] In the case of PVC plastisols which comprise as plasticizers
at least one compound of the general formula (I) and at least one
plasticizer different from the compounds (I), the total plasticizer
fraction is customarily from 5 to 400 phr, preferably from 50 to
200 phr.
[0224] Plastisols are usually converted to the form of the finished
product at ambient temperature via various processes, such as
spreading processes, casting processes, such as the slush molding
process or rotomolding process, dip-coating process, spray process,
and the like. Gelling then takes place via heating, whereupon
cooling gives a homogeneous product with relatively high or
relatively low flexibility.
[0225] PVC plastisols are particularly suitable for producing PVC
foils, for producing seamless hollow bodies, for producing gloves,
and for use in the textile sector, e.g. for textile coatings.
[0226] Molding Composition Applications
[0227] The molding composition of the invention is preferably used
for producing moldings and foils. Among these are in particular
tooling; apparatuses; piping; cables; hoses, for example plastic
hoses, water hoses, and irrigation hoses, industrial rubber hoses,
or chemical hoses; wire sheathing; window profiles;
vehicle-construction components, for example bodywork constituents,
vibration dampers for engines; tires; furniture, for example
chairs, tables, or shelving; cushion foam and mattress foam;
tarpaulins, for example lorry tarpaulins or tent tarpaulins;
gaskets; composite foils, such as foils for laminated safety glass,
in particular for vehicle windows and for window panes; recording
disks; synthetic leather; packaging containers; adhesive-tape
foils, coatings, computer housings, and housings of electrical
devices, for example kitchen machines.
[0228] The molding composition of the invention is also suitable
for producing moldings and foils which come directly into contact
with people or with foods. These primarily are medical products,
hygiene products, packaging for food or drink, products for the
interior sector, toys and child-care items, sports and leisure
products, apparel, and also fibers for textiles, and the like.
[0229] The medical products which can be produced from the molding
composition of the invention are by way of example tubes for
enteral nutrition and hemodialysis, breathing tubes, infusion
tubes, infusion bags, blood bags, catheters, tracheal tubes,
gloves, breathing masks, or disposal syringes.
[0230] The packaging that can be produced from the molding
composition of the invention for food or drink is by way of example
freshness-retention foils, food-or-drink hoses, drinking-water
hoses, containers for storing or freezing food or drink, lid
gaskets, closure caps, crown corks, or synthetic corks for
wine.
[0231] The products which can be produced from the molding
composition of the invention for the interior sector are by way of
example floorcoverings, which may have a uniform construction or a
construction comprising a plurality of layers, consisting of at
least one foamed layer, such as, for example, floorcoverings,
sports floors, or luxury vinyl tiles (LVT), synthetic leathers,
wallcoverings, or foamed or unfoamed wall papers in buildings, or
are cladding or console covers in vehicles.
[0232] The toys and child-care items which can be produced from the
molding composition of the invention are by way of example dolls,
inflatable toys, such as balls, toy figures, modeling clays,
swimming aids, stroller covers, baby-changing mats, bed warmers,
teething rings, or bottles.
[0233] The sports and leisure products that can be produced from
the molding composition of the invention are by way of example
gymnastics balls, exercise mats, seat cushions, massage balls and
massage rolls, shoes and shoe soles, balls, air mattresses, and
drinking bottles.
[0234] The apparel that can be produced from the molding
compositions of the invention is by way of example latex clothing,
protective apparel, rain jackets, or rubber boots.
[0235] Non-PVC Applications:
[0236] The present invention also includes the use of the compounds
of the invention as and/or in auxiliaries selected from:
calendering auxiliaries; rheology auxiliaries; surfactant
compositions, such as flow aids and film-forming aids, defoamers,
antifoams, wetting agents, coalescing agents, and emulsifiers;
lubricants, such as lubricating oils, lubricating greases, and
lubricating pastes; quenchers for chemical reactions; phlegmatizing
agents; pharmaceutical products; plasticizers in adhesives; impact
modifiers and antiflow additives.
[0237] The figures described below and the examples provide further
explanation of the invention. These figures and examples are not to
be understood as restricting the invention.
[0238] The following abbreviations are used in the examples and
figures below: [0239] 2,5-FDCA for 2,5-furandicarboxylic acid,
[0240] 2,5-THFDCA for 2,5-tetrahydrofurandicarboxylic acid, [0241]
DMAP for 4-dimethylaminopyridine, [0242] TBME for tert-butyl methyl
ether, [0243] THF for tetrahydrofuran, phr for parts by weight per
100 parts by weight of polymer.
DESCRIPTION OF FIGURES
[0244] FIG. 1 shows, in the form of a bar chart, the Shore A
hardness of flexible PVC test specimens which comprise different
amounts of the plasticizer 2,5-THFDCA dibutyl ester (white hatched)
and, as comparison, the commercially available plasticizer
Mesamoll.RTM. TP-LXS 51067 (black). The Shore A hardness has been
plotted against the plasticizer content of the flexible PVC test
specimens (stated in phr). The values measured were always
determined after a time of 15 seconds.
[0245] FIG. 2 shows, in the form of a bar chart, the Shore D
hardness of flexible PVC test specimens which comprise 50 and,
respectively, 70 phr of the plasticizer 2,5-THFDCA dibutyl ester of
the invention (white hatched) and, as comparison, the commercially
available plasticizer Mesamoll.RTM. TP-LXS 51067 (black). The Shore
D hardness has been plotted against the plasticizer content of the
flexible PVC test specimens (stated in phr). The values measured
were always determined after a time of 15 seconds.
[0246] FIG. 3 shows, in the form of a bar chart, the 100% modulus
of flexible PVC test specimens which comprise 50 and, respectively,
70 phr of the plasticizer 2,5-THFDCA dibutyl ester of the invention
(white hatched) and, as comparison, the commercially available
plasticizer Mesamoll.RTM. TP-LXS 51067 (black). The 100% modulus
has been plotted against the plasticizer content of the flexible
PVC test specimens (stated in phr).
[0247] FIG. 4 shows, in the form of a bar chart, the cold crack
temperature of flexible PVC foils which comprise the plasticizer
2,5-THFDCA dibutyl ester of the invention and, as comparison, the
commercially available plasticizer Mesamoll.RTM. TP-LXS 51067. The
chart shows the cold crack temperature in .degree. C. for flexible
PVC foils with plasticizer content of 50 and 70 phr.
[0248] FIG. 5 shows, in the form of a bar chart, the glass
transition temperature (T.sub.g) of flexible PVC foils which
comprise the plasticizer 2,5-THFDCA dibutyl ester of the invention
and, as comparison, the commercially available plasticizer
Mesamoll.RTM. TP-LXS 51067. The chart shows the glass transition
temperature (T.sub.g) .degree. C. for flexible PVC foils with
plasticizer content of 50 and 70 phr.
EXAMPLES
I) Production Examples
Example 1
[0249] Synthesis of di(n-butyl) 2,5-tetrahydrofurandicarboxylate
from dimethyl 2,5-furandicarboxylate via transesterification and
hydrogenation
Example 1.1
Production of dimethyl 2,5-furandicarboxylate (=Step a)
[0250] 3.30 kg of methanol were used as initial charge together
with 0.10 kg of concentrated sulfuric acid in a 10 L glass reactor
equipped with heating jacket, reflux condenser, and mechanical
stirrer. 1.6 kg of 2,5-furandicarboxylic acid (2,5-FDCA) were
slowly added to this mixture, with vigorous stirring. The dense
white suspension that forms was then heated to 70.degree. C.
(reflux). The course of the reaction was monitored by means of HPLC
analysis, whereupon after about 20 h a clear solution was obtained,
with complete conversion of the 2,5-FDCA. The reaction mixture was
then cooled to 65.degree. C., and neutralized with saturated
NaHCO.sub.3 solution and solid NaHCO.sub.3 (pH 7). During the
neutralization, a dense white suspension again formed, and was
cooled to 10.degree. C., stirred for a further 0.5 h, and then
filtered by way of a P2 sintered glass frit. The filtercake was
washed three times with 1 L of cold water, whereupon about 2 kg of
wet solid was obtained. For purification and recrystallization, the
wet solid was added to 6.00 kg of 2-butanone in a 10 L glass
reactor equipped with heating jacket, reflux condenser, and
mechanical stirrer. The suspension was heated to 70.degree. C.,
whereupon a clear solution was obtained. 1.00 kg of water was then
added, and this led to formation of a brownish orange aqueous
phase. It was sometimes necessary to add 900 mL of saturated sodium
chloride solution in order to achieve phase separation. The aqueous
phase was removed, and the organic phase was cooled to 20.degree.
C., without stirring, whereupon the crystallization of the product
began (usually at about 35.degree. C.). The crystalline suspension
was then cooled to 0.degree. C. and stirred overnight. The
suspension was then filtered by way of a P2 sintered glass frit,
and the filtercake was washed with 1 L of cold methanol. The solid
residue was dried at room temperature in vacuo. The desired
dimethyl 2,5-furandicarboxylate was obtained in a yield of from 50
to 60% and in a purity of >99%. The identity and purity of the
final product was determined by means of NMR and HPLC (HPLC column:
Varian Polaris 3.mu. C18-A, 150.times.4.6 mm).
Example 1.2
Catalytic Hydrogenation (=Step b2)
[0251] A 20% by weight solution of dimethyl 2,5-furandicarboxylate
in THF was charged to a nitrogen-filled 2.5 L Hastelloy C autoclave
from Parr Instrument, equipped with a mechanical stirrer with
magnetic coupling, thermocouple, sampling tube, and baffles. 120 g
of a heterogeneous Pd/Pt catalyst (0.4% by weight of Pd/0.4% by
weight of Pt on ZrO.sub.2, produced by analogy with DE4429014,
example 6) were then added, and the nitrogen atmosphere was
replaced by a hydrogen atmosphere by filling and ventilating the
autoclave with hydrogen three times. The final pressure of hydrogen
was increased to 200 bar, and the autoclave was heated to
180.degree. C. The progress of the reaction was monitored by means
of GC analysis. After complete conversion (usually after from 40 to
60 hours), the autoclave was cooled and ventilated, and the
contents were filtered in order to remove the solid catalyst. The
solvent in the filtrate was then removed by distillation under
reduced pressure, and the retained crude product was diluted in 300
mL of tert-butyl methyl ether and transferred to a separating
funnel. The organic phase was washed twice with saturated
NaHCO.sub.3 solution and once with saturated sodium chloride
solution. The solvent and other volatile constituents were then
removed by distillation under reduced pressure. The crude product
was purified by fractional distillation, whereupon dimethyl
2,5-tetrahydrofurandicarboxylate was obtained in the form of
colorless to brownish, viscous liquid. The desired dimethyl
2,5-tetrahydrofurandicarboxylate was obtained here in a yield of
57% and in a purity of 98.2%. The identity and purity of the final
product were determined by means of NMR and GC-MS analysis (GC
column: Agilent J&W DB-5, 30 m.times.0.32 mm.times.1.0
.mu.m).
Example 1.3
Transesterification of dimethyl 2,5-tetrahydrofurandicarboxylate
(=Step c2)
[0252] 204 g (1.08 mol, 1.0 equivalent) of dimethyl
2,5-tetrahydrofurandicarboxylate were dissolved in 200 g of
n-heptane in a 2 L round-necked flask equipped with a dropping
funnel with pressure equalization, and 325 g (4.38 mol, 4.0
equivalents) of n-butanol, and also a mixed titanium(IV)
propoxide/butoxide complex (3 mol % of titanium) were added. The
mixture was heated to reflux (from 100 to 126.degree. C.) for 22
hours, with stirring. The course of the reaction was monitored by
means of GC analysis. After complete conversion, the reaction
mixture was cooled to room temperature and filtered, and the
titanium(IV) alkoxide was hydrolyzed via addition of 100 mL of
water. The two-phase mixture was transferred to a separating
funnel, the aqueous phase was removed, and the organic phase was
washed once with saturated sodium chloride solution. The solvent
and other volatile constituents were then removed by distillation
under reduced pressure. The crude product was purified by means of
fractional distillation, whereupon di(n-butyl)
2,5-tetrahydrofurandicarboxylate was obtained in the form of clear
colorless liquid in a yield of 72% and in a purity of 98.3%. The
identity and purity of the final product was determined by means of
NMR and GC-MS analysis (GC column: Agilent J&W DB-5, 30
m.times.0.32 mm.times.1.0 .mu.m).
Example 2
Synthesis of di(n-butyl) 2,5-tetrahydrofurandicarboxylate Via
Direct Esterification and Hydrogenation
Example 2.1
Production of di(n-butyl) 2,5-furandicarboxylate (=Step b1)
[0253] 445 g (6.00 mol, 4.0 equivalents) of n-butanol were used as
initial charge in 500 g of toluene in a 2 L round-necked flask
equipped with a Dean-Stark water separator and a dropping funnel
with pressure equalization. The mixture was heated to reflux, with
stirring, and 234 g (1.50 mol, 1.0 equivalent) of
2,5-furandicarboxylic acid were added, followed by 11.5 g (0.12
mol, 8 mol %) of 99.9% sulfuric acid in from 3 to 4 portions
whenever the reaction slowed. The course of the reaction was
monitored on the basis of the amount of water separated in the
Dean-Stark apparatus. After complete conversion, a specimen was
taken from the reaction mixture and analyzed by GC. The reaction
mixture was cooled to room temperature, transferred to a separating
funnel, and washed twice with saturated NaHCO.sub.3 solution. The
organic phase was washed with saturated sodium chloride solution
and dried with anhydrous Na.sub.2SO.sub.4, and the solvent was
removed under reduced pressure. The crude product was purified by
means of fractional distillation. The desired di(n-butyl)
2,5-furandicarboxylate was obtained here in a yield of 80% and in a
purity of 98.9%. The identity and purity of the final product was
determined by means of NMR and GC-MS analysis (GC column: Agilent
J&W DB-5, 30 m.times.0.32 mm.times.1.0 or Ohio Valley OV-1701
60 m.times.0.32 mm.times.0.25 .mu.m).
[0254] Catalytic Hydrogenation (=Step c1):
[0255] A 20% by weight solution of di(n-butyl)
2,5-furandicarboxylate in THF was charged to a nitrogen-filled 2.5
L Hastelloy C autoclave from Parr Instrument, equipped with a
mechanical stirrer with magnetic coupling, thermocouple, sampling
tube, and baffles. 120 g of a heterogeneous Pd/Pt catalyst (0.4% by
weight of Pd/0.4% by weight of Pt on ZrO.sub.2, produced by analogy
with DE4429014, example 6) were then added, and the nitrogen
atmosphere was replaced three times with hydrogen at
superatmospheric pressure. The final pressure of hydrogen was
increased to 200 bar, and the autoclave was heated to 180.degree.
C. The progress of the reaction was monitored by means of GC
analysis. After complete conversion (usually after from 40 to 60
hours), the autoclave was ventilated, and the contents were
filtered in order to remove the solid catalyst. The solvent in the
filtrate was then removed by distillation under reduced pressure,
and the retained crude product was diluted in 300 mL of TBME and
transferred to a separating funnel. The organic phase was washed
twice with saturated NaHCO.sub.3 solution and once with saturated
sodium chloride solution. The solvent and other volatile
constituents were then removed by distillation under reduced
pressure. The crude product was purified by fractional
distillation, whereupon di(n-butyl)
2,5-tetrahydrofurandicarboxylate was obtained in the form of
colorless to brownish, viscous liquid in a yield of 30% and in a
purity of 97.9%. The identity and purity of the final product were
determined by means of NMR and GC-MS analysis (GC column: Agilent
J&W DB-5, 30 m.times.0.32 mm.times.1.0 .mu.m).
Example 3
Synthesis of the di-n-butyl ether of
2,5-di(hydroxymethyl)tetrahydrofuran
[0256] 10.6 g of 2,5-di(hydroxymethyl)tetrahydrofuran (80 mmol, 1.0
equivalent) were dissolved in 140 ml of toluene in a 500 mL
four-necked flask equipped with a mechanical stirrer, dropping
funnel, thermometer, and reflux condenser. 22.4 g (400 mmol, 5.0
equivalents) of powdered KOH were added in portions to this mixture
at room temperature over a period of 30 minutes and with continuous
stirring. The mixture was then stirred at reflux for from 3 to 4
hours. 60.0 g of molecular sieve (3 .ANG.) were then added, and the
mixture was stirred at reflux for a further hour, whereupon a
cream-colored suspension was obtained. The mixture was cooled to
90.degree. C., and 28.5 g (208 mmol, 2.6 equivalents) of
1-bromobutane dissolved in 40 mL of toluene were added dropwise
over 1.5 hours. The dropping funnel was washed with 20 mL of
toluene, and the wash solution was combined with the reaction
mixture. The course of the reaction was monitored by means of GC
analysis. After the end of the reaction, (usually from 40 to 80
hours) the mixture was cooled to room temperature. The glass
containers were washed with TBME, combined with the reaction
mixture, and the resultant white suspension was filtered. The salt
residues removed by filtration were washed with TBME. The combined
organic phases were in each case washed in succession once with
saturated sodium chloride solution, with saturated ammonium
chloride solution, and again with saturated sodium chloride
solution, and finally dried over Na.sub.2SO.sub.4. The solvent and
other volatile constituents were then removed by distillation under
reduced pressure, and the residue was dried under high vacuum. The
crude product was purified by means of fractional distillation,
whereupon the di-n-butyl ether of
2,5-di(hydroxymethyl)tetrahydrofuran was obtained in the form of
clear colorless liquid in a yield of 55% and in a purity of 98.7%.
The identity and purity of the final product were determined by
means of NMR and GC-MS analysis (GC column: Agilent J&W DB-5,
30 m.times.0.32 mm.times.1.0 .mu.m).
II) Production of Plasticized PVC Foils on a Roll Mill and of PVC
Test Specimens
[0257] II.a) Production of PVC Foils on a Roll Mill:
[0258] To assess the plasticizing properties of the plasticizers of
the invention and of the comparative compounds during thermoplastic
processing, flexible PVC foils of thickness 0.5 mm were produced.
These foils were produced via rolling and pressing of plasticized
PVC.
[0259] In order to eliminate effects due to different additives,
the formulation below was used in each case for producing the
plasticized PVC:
TABLE-US-00001 Additive phr Solvin 271 SP.sup.1) 100 Plasticizer 50
and, respectively, 70 SLX 781.sup.2) reagent 2 .sup.1)commercially
obtainable PVC from Solvin GmbH & Co. KG, produced via
suspension polymerization (K value in accordance with ISO 1628-2:
71) .sup.2)liquid Ba--Zn stabilizer from Reagens Deutschland
GmbH
[0260] The ingredients were mixed at room temperature with a manual
mixer. The mixture was then plastified in a steam-heated laboratory
mixing unit from Collin (150) and processed to give a milled sheet.
The rotation rates were 15 rotations/minute (front roll) and 12
rotations/minute (rear roll), and the roll-milling time was 5
minutes. This gave a milled sheet of thickness 0.55 mm. The cooled
milled sheet was then pressed in a 400 P Collin press within a
period of 400 seconds under a pressure of 220 bar to give a
flexible PVC foil of thickness 0.50 mm.
[0261] The respective conditions for the roll mill and press can be
found in the table below:
TABLE-US-00002 Plasticizer Roll- content milling Pressing Ex. No.
Product [phr] [.degree. C.] [.degree. C.] 1 2,5-THFDCA di(n-butyl
ester) 50/70 160/160 160/160 comp 1 Mesamoll .RTM. TP-LXS
51067.sup.3) 50/70 175/165 185/175 .sup.3)Mixture of phenyl
alkylsulfonates from Lanxess Deutschland GmbH (CAS No.
91082-17-6)
[0262] The test specimens needed for the tests were produced from
the resultant roll-milled and pressed foils.
[0263] II.b) Production of Test Specimens:
[0264] The test specimens with dimensions 49 mm.times.49
mm.times.10 mm (length.times.width.times.thickness) were produced
via pressing from roll-milled foils at a temperature which was
10.degree. C. above the roll-milling temperature. For the
performance tests, the test specimens were aged for 7 days at
23.degree. C. and 50% relative humidity.
III) Performance Tests
[0265] III.a) Determination of Solvation Temperature in Accordance
with DIN 53408:
[0266] To characterize the gelling performance of the plasticizers
of the invention in PVC, solvation temperature was determined in
accordance with DIN 53408. In accordance with DIN 53408, a droplet
of a slurry of 1 g of PVC in 19 g of plasticizer is observed in
transmitted light under a microscope equipped with a heatable
stage. The temperature here is increased linearly by 2.degree. C.
per minute, starting at 60.degree. C. The solvation temperature is
the temperature at which the PVC particles become invisible, i.e.
it is no longer possible to discern their outlines and contrasts.
The lower the solvation temperature, the better the gelling
performance of the relevant substance for PVC.
[0267] The table below lists the solvation temperatures of the
di(n-butyl) 2,5-tetrahydrofurandicarboxylate plasticizer of the
invention and, as comparison, of Mesamoll.RTM. TP-LXS 5106, and
also of dibutyl phthalate.
TABLE-US-00003 Solvation temperature in accordance with DIN 53408
Ex. No. Substance [.degree. C.] 1 Di(n-butyl) 2,5- 71
tetrahydrofurandicarboxylate comp 1 Mesamoll .RTM. TP-LXS
51067.sup.3) 114 comp 2 Dibutyl phthalate.sup.4) 100 .sup.3)Mixture
of phenyl alkylsulfonates from Lanxess Deutschland GmbH (CAS No.
91082-17-6) .sup.4)Di(n-butyl) benzene-1,2-dicarboxylate (CAS No.
84-74-2)
[0268] As can be seen from the table, the plasticizer of the
invention exhibits the lowest salvation temperature.
[0269] III.b) Physical Properties:
[0270] The table below lists the most significant physical
properties of di(n-butyl) 2,5-tetrahydrofurandicarboxylate (example
1) in comparison with the Mesamoll.RTM. TP-LXS 51067 plasticizer
used in the market (comparative example comp 1).
TABLE-US-00004 Di(n-butyl) 2,5- tetrahydrofuran- Mesamoll .RTM. TP-
Plasticizer: dicarboxylate LXS 51067 Density (20.degree. C.) 1.048
1.071 [g/cm.sup.3] Viscosity (20.degree. C.) 10 90 [mPa s]
[0271] Relevant physical properties for the plasticizer application
alongside the salvation temperature in accordance with DIN 53408
are specifically density and viscosity. In comparison with the
plasticizer Mesamoll.RTM. TP-LXS 51067, which is commercially
available and regarded as having advantageous properties,
2,5-THFDCA dibutyl ester exhibits markedly lower, and therefore
more advantageous, viscosity with comparable density.
[0272] III.c) Shore Hardness Determination:
[0273] Shore A and D hardness were determined in accordance with
DIN EN ISO 868 with a DD-3 digital durometer from Hildebrand. The
test specimens were produced as in example II.c). The values shown
in FIG. 1 and FIG. 2 are in each case the average value from 20
measurements per test specimen (10 measurements on the front side
and 10 measurements on the reverse side). The value measured was
always determined after a time of 15 seconds.
[0274] As can be seen from the charts of FIG. 1 and FIG. 2,
2,5-THFDCA dibutyl ester of the invention exhibits markedly better
plasticizing effect than the commercially available plasticizer
Mesamoll.RTM. TP-LXS 51067.
[0275] III.d) Determination of 100% Modulus:
[0276] 100% modulus is another property, alongside Shore hardness,
that characterizes the plasticizing effect of plasticizers, i.e.
plasticizer efficiency.
[0277] 100% modulus was determined in accordance with DIN EN ISO
527 part 1 and 3 with a TMZ 2.5/TH1S tester from Zwick. The test
specimens of dimensions 150 mm.times.10 mm.times.0.5 mm
(length.times.width.times.thickness) correspond to type 2 in
accordance with DIN EN ISO 527 part 3, and are punched out from the
rolled/pressed foils by means of a hole punch. The test specimens
are conditioned for 7 days before the test. The conditioning and
the tensile tests take place at 23.degree. C.+/-1.0.degree. C. and
50%+/-5 relative humidity in accordance with DIN EN ISO 291. The
values plotted in FIG. 3 are in each case average values from the
testing of 10 individual test specimens.
[0278] As can be seen from the chart of FIG. 3, 2,5-THFDCA dibutyl
ester of the invention exhibits markedly better plasticizing effect
than the commercially available plasticizer Mesamoll.RTM. TP-LXS
51067.
[0279] III.e) Determination of Low-Temperature Flexibility:
[0280] To determine low-temperature flexibility, PVC foils were
used which comprised different concentrations of the respective
plasticizer to be tested. Two methods were used. Firstly, cold
crack temperature was determined by a method based on the standard
DIN 53372, which is no longer current, and secondly the glass
transition temperature T.sub.g of the foils was determined by means
of DMA (dynamic mechanical analysis) in accordance with ISO 6721-7
from the maximum of the loss modulus "G". FIGS. 4 and 5 show the
results from the two test methods.
[0281] As is apparent from the charts of FIGS. 4 and 5, the PVC
foils which comprise 2,5-THFDCA dibutyl ester of the invention
exhibit a lower, and thus more advantageous, cold crack temperature
in comparison with PVC foils using Mesamoll.RTM. TP-LXS 51067. The
same applies to the glass transition temperature. The excellent
value for the glass transition temperature of 2,5-THFDCA dibutyl
ester of the invention at 70 phr plasticizer content is
surprising.
* * * * *