U.S. patent application number 13/997338 was filed with the patent office on 2013-11-07 for hybrid mixtures for gas hydrate inhibition applications.
This patent application is currently assigned to AKZO NOBEL CHEMICALS INTERNATIONAL B.V.. The applicant listed for this patent is Stuart Holt, John S. Thomaides. Invention is credited to Stuart Holt, John S. Thomaides.
Application Number | 20130292611 13/997338 |
Document ID | / |
Family ID | 45401091 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130292611 |
Kind Code |
A1 |
Holt; Stuart ; et
al. |
November 7, 2013 |
HYBRID MIXTURES FOR GAS HYDRATE INHIBITION APPLICATIONS
Abstract
A method of inhibiting gas hydrates comprises contacting gas
hydrates with a hybrid mixture including a copolymer of at least
one ethylenically unsaturated monomer and a naturally derived
hydroxyl containing chain transfer agent.
Inventors: |
Holt; Stuart; (Chicago,
IL) ; Thomaides; John S.; (Berkeley Heights,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Holt; Stuart
Thomaides; John S. |
Chicago
Berkeley Heights |
IL
NJ |
US
US |
|
|
Assignee: |
AKZO NOBEL CHEMICALS INTERNATIONAL
B.V.
Amersfoort
NL
|
Family ID: |
45401091 |
Appl. No.: |
13/997338 |
Filed: |
December 23, 2011 |
PCT Filed: |
December 23, 2011 |
PCT NO: |
PCT/EP2011/073928 |
371 Date: |
June 24, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61427940 |
Dec 29, 2010 |
|
|
|
Current U.S.
Class: |
252/403 |
Current CPC
Class: |
F17D 1/16 20130101; F17D
3/12 20130101; C10L 3/06 20130101; C09K 2208/22 20130101; F17D 1/00
20130101; C10L 3/107 20130101; C09K 8/52 20130101; C10L 1/221
20130101 |
Class at
Publication: |
252/403 |
International
Class: |
C10L 3/10 20060101
C10L003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2011 |
EP |
11158599.8 |
Claims
1. A method of inhibiting gas hydrates comprising: contacting a gas
hydrate with a hybrid mixture formed by combining at least one
ethylenically unsaturated monomer with a solution of at least one
naturally derived hydroxyl containing chain transfer agent and a
non-metal ion initiator at a temperature effective to initiate
polymerization of the at least one ethylenically unsaturated
monomer and the naturally derived hydroxyl containing chain
transfer agent, wherein the naturally derived hydroxyl containing
chain transfer agent is a hydroxyl containing moiety obtained from
plant sources directly or by enzymatic or fermentation
processes.
2. The method of claim 1 wherein the naturally derived hydroxyl
containing chain transfer agent is a polysaccharide.
3. The method of claim 1 wherein the naturally derived hydroxyl
containing chain transfer agent is a polysaccharide.
4. The method of claim 1 wherein at least one naturally derived
hydroxyl containing chain transfer agent is a monosaccharide or a
disaccharide.
5. The method of claim 4 wherein the at least one naturally derived
hydroxyl containing chain transfer agent is selected from the group
consisting of glucose, galactose, mannose, fructose, arabinose,
xylose, maltose, lactose, trehalose, cellobiose, maltotriose, and
sucrose and combinations thereof.
6. The method of claim 1 wherein the at least one ethylenically
unsaturated monomer is a vinyl lactam or a vinyl lactam with a
co-monomer.
7. The method of claim 6 wherein the ethylenically unsaturated
monomer is N-vinyl pyrrolidone or vinyl caprolactam or combinations
thereof.
8. The method of claim 1 wherein the chain transfer agent has an
average molecular weight of about 100,000 or less.
9. The method of claim 1 wherein about 35% to about 90% by weight
of the hybrid mixture is derived from the naturally derived
hydroxyl containing chain transfer agent.
10. The method of claim 1 wherein about 40% to about 60% by weight
of the hybrid mixture is derived from the naturally derived
hydroxyl containing chain transfer agent.
11. The method of claim 11 wherein the initiator is an azo
initiator, a tert-butyl hydroperoxide and erythorbic acid redox
system, and peroxide and an amine.
12. The method of claim 12 wherein the azo initiator is selected
from the group consisting of
2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride,
2,2'-Azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate,
2,2'-Azobis(2-methylpropionamidine)dihydrochloride,
2,2'-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate,
2,2'-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochlori-
de, 2,2'-Azobis[2-(2-imidazolin-2-yl)propane],
2,2'-Azobis(1-imino-1-pyrrolidino-2-ethylpropane)dihydrochloride,
2,2'-Azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethl]propionamide-
} and 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] and
combinations thereof.
13. The method of claim 2 wherein the polysaccharide is a
hydrolyzed starch having a dextrose equivalent of 9 or greater.
14. The method of claim 2 wherein the polysaccharide is
maltodextrin having a dextrose equivalent of about 13.0 to about
17.0
15. The method of claim 1 wherein the at least one ethylenically
unsaturated monomer is anionic.
16. The method of claim 1 wherein the at least one ethylenically
unsaturated monomer is non-anionic.
17. The method of claim 14 wherein the at least one ethylenically
unsaturated monomer is cationic.
18. The method of claim 14 wherein the at least one ethylenically
unsaturated monomer is nonionic.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method of inhibiting gas
hydrates comprising contacting gas hydrates with a hybrid mixture
comprising a derivative of at least one ethylenically unsaturated
monomer and a naturally derived hydroxyl containing chain transfer
agent.
BACKGROUND
[0002] Gas hydrates, also called clathrate hydrates, are
crystalline water-based solids physically resembling ice, in which
small non polar molecules (typically gases) are trapped inside
"cages" of hydrogen bonded water molecules. Most low molecular
weight gases (including O.sub.2, H.sub.2, N.sub.2, CO.sub.2,
CH.sub.4, H.sub.2S, Ar, Kr, and Xe), as well as some higher
hydrocarbons, form hydrates at suitable temperatures and pressures.
Undesirably, gas hydrates may occur when water is present in
mineral oil mixtures or in natural gas mixtures in which gas
hydrate crystals may agglomerate and plug, for example,
pipelines.
[0003] To inhibit gas hydrate formation, certain polymers or
copolymers have been used to inhibit gas hydrate formation.
However, increasingly stringent regulations regarding toxicity and
degradability of oilfield chemicals and polymers have made
conventional gas hydrate inhibitors less desirable. The leading
conventional gas hydrate inhibiting polymers are not readily
biodegradable under the conditions specified by the regulatory
bodies. Thus, there is a need to provide improved gas hydrate
inhibitors to meet the industries' needs.
SUMMARY OF THE INVENTION
[0004] Accordingly, it has been found that hybrid mixtures
according to the present invention can address the problems
associated with conventional gas hydrate inhibitors, including
improving biodegradability. Hybrid mixtures comprise a naturally
occurring oligomer or polymer and a synthetically derived oligomer
or polymer. In addition, new combinations of naturally derived
hydroxyl containing chain transfer agents in gas hydrate inhibition
applications have been discovered that were heretofore previously
unknown.
[0005] In an aspect, the invention is directed to a method of
inhibiting gas hydrates comprising contacting a gas hydrate with a
hybrid mixture comprising a derivative of at least one
ethylenically unsaturated monomer and a naturally derived hydroxyl
containing chain transfer agent. In a first embodiment, the
derivative of the at least one ethylenically unsaturated monomer is
a polymer including the ethylenically unsaturated monomer. In a
second embodiment, the derivative is a polymeric chain comprised of
the ethylenically unsaturated monomer that is attached covalently
to the naturally derived hydroxyl containing chain transfer agent.
In a further embodiment, the derivative may include a combination
of the first and second embodiments.
[0006] In another aspect, the invention is directed to a method of
inhibiting gas hydrates comprising contacting a gas hydrate with a
hybrid mixture formed by combining at least one ethylenically
unsaturated monomer with a solution of a naturally derived hydroxyl
containing chain transfer agent and an initiator at a temperature
effective to activate the initiator.
BRIEF DESCRIPTION OF THE DRAWING
[0007] The invention is best understood from the following detailed
description when read in connection with the accompanying drawings.
Included in the drawings is the following FIGURE:
[0008] The FIGURE is a chart illustrating rapid hydrate formation
time and temperature data from the evaluation of the hybrid mixture
of Synthesis Example 24.
DETAILED DESCRIPTION OF THE INVENTION
[0009] Generally, the invention is directed to a method of
inhibiting gas hydrates. The method includes contacting the gas
hydrates with a hybrid mixture. The hybrid mixtures of the instant
invention are formed by combining at least one ethylenically
unsaturated monomer with a solution containing a naturally derived
hydroxyl containing chain transfer agent and an initiator at a
temperature effective to activate the initiator.
[0010] In an aspect, the invention relates to a method of
inhibiting gas hydrates wherein the method comprises contacting a
gas hydrate with a hybrid mixture comprising a derivative of at
least one ethylenically unsaturated monomer and a naturally derived
hydroxyl containing chain transfer agent. In an embodiment, the
hybrid mixture that is used to inhibit gas hydrates is an intimate
mixture of at least one naturally derived hydroxyl containing chain
transfer agent and a polymer comprised of at least one
ethylenically unsaturated monomer. This intimate mixture can be
prepared by polymerization of the at least one ethylenically
unsaturated monomer, by means known to those skilled in art, in the
presence of the at least one naturally derived hydroxyl containing
chain transfer agent.
[0011] The intimate mixture can also be prepared by coprocessing
the at least one naturally derived hydroxyl containing chain
transfer agent with the polymer comprised of at least one
ethylenically unsaturated monomer under conditions of high
temperature or pressure or both. An example of coprocessing under
conditions of high pressure and high temperature is to co jet cook
the at least one naturally derived hydroxyl containing chain
transfer agent with the polymer comprised of at least one
ethylenically unsaturated monomer. Another example of coprocessing
is heating the at least one naturally derived hydroxyl containing
chain transfer agent with the polymer comprised of at least one
ethylenically unsaturated monomer in aqueous solution under
atmospheric pressure. In an embodiment, the derivative of the at
least one ethylenically unsaturated monomer is a polymer including
the ethylenically unsaturated monomer.
[0012] In another embodiment, the hybrid mixture is a hybrid
copolymer composition prepared by reacting at least one
ethylenically unsaturated monomer with a solution of a naturally
derived hydroxyl containing chain transfer agent and an initiator.
One conventional method of making hybrid mixtures utilizes water
soluble monomers in the presence of an aqueous solution of a
naturally derived, hydroxyl containing material as a chain transfer
agent. Such a method is disclosed in U.S. Patent application
publication number US 2007-0021577 A1, which is wholly incorporated
herein by reference. In an embodiment, the derivative is a
polymeric chain comprised of the ethylenically unsaturated monomer
that is attached covalently to the naturally derived hydroxyl
containing chain transfer agent.
[0013] In this embodiment, the hybrid copolymer composition can be
prepared with a naturally derived hydroxyl containing chain
transfer agent and still maintain the functionality of the
synthetic polymers portion. Without wishing to be bound by theory,
in this embodiment, it is believed that the reaction proceeds
according to the following mechanism:
##STR00001##
In the first step the initiator I forms free radicals which reacts
with the monomer and initiates the synthetic polymer chain. This
then propagates by reacting with several monomer moieties.
Termination is then by chain transfer which abstracts a proton from
the chain transfer agent. This terminates the hybrid synthetic
polymer (a) and produces a free radical on the chain transfer
agent. The chain transfer agent then reacts with several monomer
moieties to form a species in which the naturally derived hydroxyl
containing chain transfer agent is connected to the synthetic
polymer chain. This species can then terminate by chain transfer
mechanism or reaction with an initiator fragment or by some other
termination such as combination or disproportionation reaction to
produce the hybrid copolymer (b). If the termination is by chain
transfer, then R.sub.1 is H (abstracted from the chain transfer
moiety) and the chain transfer agent can then initiate another
chain.
[0014] Accordingly, as shown in the above reaction, a "hybrid
copolymer composition" is a mixture of (a) a hybrid synthetic
copolymer and (b) a hybrid copolymer. The hybrid copolymer
composition thus contains the two moieties, (a) and (b), with a
minimum amount of the hybrid synthetic copolymer (a) since this
component generates the chain transfer which leads to the formation
of the hybrid copolymer (b). One skilled in the art will recognize
that the hybrid copolymer composition may contain a certain amount
of the unreacted chain transfer agent.
[0015] The term "hybrid copolymer", as defined herein, refers to a
copolymer of synthetic monomers with an end group containing the
naturally derived hydroxyl containing chain transfer agent which is
a result of the hybrid synthetic copolymer chain transfer. The term
"naturally derived hydroxyl containing chain transfer aged' as used
herein, means a hydroxyl containing moiety obtained from plant
sources directly or by enzymatic or fermentation processes. In an
embodiment of the invention, the hybrid copolymer has the following
structure:
##STR00002##
where C is a moiety derived from the naturally derived hydroxyl
containing chain transfer agent, M.sub.hc is the synthetic portion
of the hybrid copolymer derived from one or more ethylenically
unsaturated monomers and R.sub.1.dbd.H from chain transfer or I
from reaction with the initiator radical or the naturally derived
hydroxyl containing chain transfer agent or another moiety formed
from a termination reaction.
[0016] In an embodiment, the attachment point between C and
M.sub.hc is through an aldehyde group in C which results in the
link between C and M.sub.hc being a carbonyl moiety. In another
embodiment, when the naturally derived hydroxyl containing chain
transfer agent is a saccharide/polysaccharide with an aldehyde
group as the reducing end group, then the hybrid copolymer can be
represented by the structure:
##STR00003##
Where S is a saccharide repeat unit from the
saccharide/polysaccharide chain transfer agent and s is an integer
from 0 to 1000 and p is an integer that is 3, 4 or 5. In another
embodiment, when the naturally derived hydroxyl containing chain
transfer agent is an oxidized starch which contains aldehyde
groups, the hybrid copolymer can be represented by the
structure:
##STR00004##
[0017] Also as used herein, the term "hybrid synthetic copolymer"
is a synthetic polymer derived from synthetic monomers with a
hybrid initiator fragment as one end group. The other end group is
a proton resulting from chain transfer to the naturally derived
hydroxyl containing chain transfer agent. As used herein, the term
"synthetic monomer" means any ethylenically unsaturated monomer
which can undergo free radical polymerization.
[0018] In an embodiment of the invention, an exemplary hybrid
synthetic copolymer has the following structure:
##STR00005##
[0019] Where I is the initiator fragment, H is the proton
abstracted from the natural chain transfer agent and M.sub.hsc is
the synthetic portion of the hybrid synthetic copolymer derived
from one or more ethylenically unsaturated monomers. One skilled in
the art will recognize that if one or more ethylenically
unsaturated monomers are used, the average composition of M.sub.hsc
and M.sub.hc will be the same.
[0020] One skilled in the art will recognize that the hybrid
initiator fragment incorporated into the hybrid synthetic copolymer
will depend on the hybrid initiator used. For example, sodium
persulfate, potassium persulfate and ammonium persulfate will
incorporate sulfate initiator fragments, whereas an azo initiator,
such as 2,2'-Azobis(2-methylpropionamidine)dihydrochloride, will
incorporate a 2-methyl propane propionamidine hydrochloride
fragment.
[0021] One skilled in the art will recognize, that the minimum
amount of the hybrid synthetic copolymer will depend on the
relative amounts of synthetic monomer, initiator and naturally
derived hydroxyl containing chain transfer agent.
[0022] In an embodiment, a secondary chain transfer agent may also
be included. The secondary chain transfer agent may be less than 20
weight percent of the hybrid polymer. In another embodiment,
solution of the naturally derived hydroxyl containing chain
transfer agent may be substantially free of secondary transfer
agents. The process may further comprise catalyzing the
polymerizing step with an initiator that is substantially free of a
metal ion initiating system at a temperature sufficient to activate
said initiator.
[0023] Molecular weight of the hybrid synthetic polymer is
determined by the relative amounts of synthetic monomer, initiator
and naturally derived hydroxyl containing chain transfer agent.
[0024] Optionally, in an embodiment of the present invention, the
weight average molecular weight of the hybrid copolymer composition
may be less than about 500,000, preferably less than 300,000 and
most preferably less than 100,000. In a further embodiment, the
hybrid copolymer composition may be water soluble. For purposes of
the present application, water soluble is defined as having a
solubility of greater than about 0.1 grams per 100 grams of water
at 25.degree. C. and preferably 1 gram per 100 grams of water at
25.degree. C.
[0025] In another embodiment, the hybrid synthetic copolymer will
have a hybrid initiator fragment (I) and some of the hybrid
copolymer chains will have a natural chain transfer agent at one
end and a hybrid initiator fragment (where R.sub.1 is I) at the
other end of the synthetic polymer chain. As used herein, the term
"hybrid initiator fragment" is any fragment of the hybrid initiator
that gets incorporated into a synthetic polymer derived from a
hybrid initiator. In an embodiment, I is preferably 0.01 to 20 mole
% of M.sub.hc+M.sub.hsc and more preferably I is 0.1 to 15 mole %
of M.sub.hc+M.sub.hsc and most preferably I is 1 to 10 mole % of
M.sub.hc+M.sub.hsc.
[0026] In an embodiment of the invention, the naturally derived
hydroxyl containing chain transfer agents include, but are not
limited, to small molecules such as glycerol, citric acid, lactic
acid, tartaric acid, gluconic acid, ascorbic acid, and
glucoheptonic acid. The naturally derived hydroxyl containing chain
transfer agents may also include saccharides or derivatives
thereof. Suitable saccharides include, for example, monosaccharides
and disaccharides such as sugars, such as glucose, galactose,
mannose, fructose, arabinose, xylose, maltose, lactose, trehalose,
cellobiose, maltotriose, and sucrose, as well as larger molecules
such as oligosaccharides and polysaccharides (e.g., corn syrup
solids, maltodextrins, pyrodextrins and starches). In an embodiment
of the invention, the naturally derived chain transfer agent is
maltodextrin, pyrodextrin or a low molecular weight starch. It has
been found that the chain transfer reaction does not work well when
the chain transfer agent is not soluble in the system. For example,
high molecular weight starches, such as those having molecular
weights in the millions or those in granular form, are water
dispersible and not water soluble. Accordingly, in embodiments of
the invention, the average molecular weight of the chain transfer
agent is preferably less than about 500,000 based on a starch
standard. Starches having such exemplary molecular weights are
water soluble. In another embodiment, the average molecular weight
(Mw) of the chain transfer agent may be less than about 100,000. In
yet another preferred embodiment, the weight average molecular
weight of the chain transfer agent may be less than about 50,000.
In yet another preferred embodiment, the weight average molecular
weight of the chain transfer agent may be less than about 10,000.
It has also been determined that for applications in which
dispersancy and scale control is particularly desirable, a lower
molecular weight, such as 10,000, of the chain transfer agent
provides improved performance.
[0027] The molecular weight of the polysaccharide was determined by
the procedure outlined below: [0028] Eluent: 0.025M
NaH.sub.2PO.sub.4, 0.025 M Na.sub.2HPO.sub.4 and 0.01M of Sodium
Azide in HPLC grade water. This solution was filtered through a 0.2
.mu.m filter. [0029] Columns: 1 x G6000PWx1 7.8 mm.times.30
cm,G4000PWx1 7.8.times.30 cm, G3000PWx1 [0030] 7.8 mm.times.30 cm,
Guard column is TSKgel Guard PWx1 6.0 mm.times.4 cm (all made by
Tosoh Bioscience) [0031] The column bank was controlled to
5.degree. C. above ambient temperature. Usually 30.degree. C.
[0032] Flow Rate: 1.0 ml/min [0033] Detector: Refractive Index,
Waters.RTM. Model 2414 Temperature controlled to 30.degree. C.
[0034] Pump/Autosampler: Waters.RTM. e2695 Separation Module.
Sample compartment temperature controlled to 25.degree. C. [0035]
Primary Standards: HETA (Hydroxyethylstarch). Available from
American Polymer Standards Corporation. (www.ampolymer.com) 5
standards. Prepare a 0.1% w/w in the mobile phase of each of the
following:
TABLE-US-00001 [0035] 1. Mw 9,600 Mn 5,400 2. Mw 25,900 Mn 10,600
3. Mw 51,100 Mn 34,300 4. Mw 114,300 Mn 58,000 5. Mw 226,800 Mn
95,900
[0036] Sample Preparation: The samples were prepared by dissolving
the polymer in the mobile phase at a 0.1% concentration. [0037]
Injection Volume: 450 .mu.l for the standard and sample. [0038] The
standards are injected and a first or second order calibration
curve is built. [0039] The curve with the best fit and within the
range of the molecular weight of the unknown sample was then
chosen. [0040] Software: Empower.RTM. 2 by Waters Corporation
[0041] A calibration curve is first built with the samples of the
standards. The molecular weight of the unknown sample is then
determined by comparing its elution time with the elution time of
the standards.
[0042] The naturally derived hydroxyl containing chain transfer
agents also may include cellulose and its derivatives, as well as
inulin and its derivatives, such as carboxymethyl inulin. The
cellulosic derivatives include plant heteropolysaccharides commonly
known as hemicelluloses which are by products of the paper and pulp
industry. Hemicelluloses include xylans, glucuronoxylans,
arabinoxylans, arabinogalactans, glucomannans, and xyloglucans.
Xylans are the most common heteropolysaccharide and are preferred.
In an embodiment of the invention, cellulosic derivatives such as
heteropolysaccharides such as xylans may be present in an amount of
from about 0.1% to about 98% by weight, based on the total amount
of the hybrid copolymer. In an embodiment of this invention the
naturally derived chain transfer agents may be maltodextrins,
pyrodextrins and chemically modified versions of maltodextrins and
pyrodextrins. In another embodiment, the naturally derived chain
transfer agent may be cellulose of inulin or chemically modified
cellulose or inulin or a heteropolysaccharide such as xylan or a
lignin derivative, such as lignosulfonate.
[0043] The naturally derived hydroxyl containing chain transfer
agents also may include polysaccharides and polysaccharide gums.
Examples of polysaccharides and polysaccharide gums include but are
not limited guar gum, locust bean gum, gum arabic alginic acid,
pectin, chitin, chitosan, xanthan gum, and tamarind kernel gum.
[0044] The naturally derived chain transfer agents can be used as
obtained from their natural source or they can be chemically
modified. Chemical modification includes hydrolysis by the action
of acids, enzymes, oxidizers or heat, esterification or
etherification. The modified naturally derived chain transfer
agents, after undergoing chemical modification may be cationic,
anionic, non-ionic or amphoteric or hydrophobically modified. In an
embodiment of the invention, the hybrid copolymer may optionally be
formed by polymerization catalyzed by, for example, a non-metal
based radical initiator system.
[0045] In an embodiment of the present invention, the gas hydrate
inhibitor comprises a hybrid mixture wherein the derivative of the
at least one ethylenically unsaturated monomer includes at least
one anionic ethylenically unsaturated monomer. As used herein, the
term "anionic ethylenically unsaturated monomer" means an
ethylenically unsaturated monomer which is capable of introducing a
negative charge to the anionic hybrid mixture. These anionic
ethylenically unsaturated monomers can include, but are not limited
to, acrylic acid, methacrylic acid, ethacrylic acid,
.alpha.-chloro-acrylic acid, .alpha.-cyano acrylic acid,
.beta.-methyl-acrylic acid (crotonic acid), .alpha.-phenyl acrylic
acid, .beta.-acryloxy propionic acid, sorbic acid, .alpha.-chloro
sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid,
.beta.-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3),
itaconic acid, maleic acid, citraconic acid, mesaconic acid,
glutaconic acid, aconitic acid, fumaric acid, tricarboxy ethylene,
muconic acid, 2-acryloxypropionic acid, 2-acrylamido-2-methyl
propane sulfonic acid, vinyl sulfonic acid, sodium methallyl
sulfonate, sulfonated styrene, allyloxybenzene sulfonic acid, vinyl
phosphonic acid and maleic acid. Moieties such as maleic anhydride
or acrylamide that can be derivatized (hydrolyzed) to moieties with
a negative charge are also suitable. Combinations of anionic
ethylenically unsaturated monomers can also be used. In an
embodiment of the invention, the anionic ethylenically unsaturated
monomer may preferably be acrylic acid, maleic acid, methacrylic
acid, itaconic acid, 2-acrylamido-2-methyl propane sulfonic acid or
mixtures thereof.
[0046] In an embodiment, the anionic hybrid mixture comprises an
anionic hybrid copolymer composition, which may contain 1 to 99.5
weight percent of the naturally derived hydroxyl containing chain
transfer agent based on the weight of the hybrid copolymer mixture.
Based on the conventional understanding of one of ordinary skill in
the art, one would expect that the performance of the inventive
anionic hybrid copolymer mixtures would decrease as the weight
percent of the chain transfer agent in the polymer increases. For
example, polysaccharides have little to no performance as
dispersants by themselves. Surprisingly, however, it has been found
that when the chain transfer agent content of the polymer is
greater than 50 weight percent or more of the hybrid mixture,
performance is still maintained.
[0047] In another embodiment, the present invention relates to gas
hydrate inhibitors comprising hybrid mixtures in which the at least
one ethylenically unsaturated monomer includes at least one
non-anionic ethylenically unsaturated monomer. A hybrid mixture
that is non-anionic, as used herein, includes mixtures produced
from at least one cationic ethylenically unsaturated monomer or at
least one nonionic ethylenically unsaturated monomer or a
combination of cationic and non-ionic ethylenically unsaturated
monomers and a naturally derived hydroxyl containing chain transfer
agent. In an embodiment, the "cationic ethylenically unsaturated
monomer" is capable of introducing a positive charge to a
non-anionic hybrid mixture. In an embodiment of the present
invention, the cationic ethylenically unsaturated monomer has at
least one amine functionality. Cationic derivatives of non-anionic
hybrid copolymer compositions may be formed by forming amine salts
of all or a portion of the amine functionality, by quaternizing all
or a portion of the amine functionality to form quaternary ammonium
salts, or by oxidizing all or a portion of the amine functionality
to form N-oxide groups.
[0048] As used herein, the term "amine salt" means the nitrogen
atom of the amine functionality is covalently bonded to from one to
three organic groups and is associated with an anion.
[0049] As used herein, the term "quaternary ammonium salt" means
that a nitrogen atom of the amine functionality is covalently
bonded to four organic groups and is associated with an anion.
These cationic derivatives can be synthesized by functionalizing
the monomer before polymerization or by functionalizing the polymer
after polymerization. These cationic ethylenically unsaturated
monomers include, but are not limited to, N,N
dialkylaminoalkyl(meth)acrylate, N-alkylaminoalkyl(meth)acrylate,
N,N dialkylaminoalkyl(meth)acrylamide and
N-alkylaminoalkyl(meth)acrylamide, where the alkyl groups are
independently C.sub.1-18 aliphatic, cycloaliphatic, aromatic, or
alkyl aromatic and the like. Aromatic amine containing monomers
such as vinyl pyridine and vinyl imidazole may also be used.
Furthermore, monomers such as vinyl formamide, vinyl acetamide and
the like which generate amine moieties on hydrolysis may also be
used. Preferably the cationic ethylenically unsaturated monomer is
N,N-dimethylaminoethyl methacrylate,
tert-butylaminoethylmethacrylate and N,N-dimethylaminopropyl
methacrylamide.
[0050] Cationic ethylenically unsaturated monomers that may be used
are the quaternized derivatives of the above monomers as well as
diallyldimethylammonium chloride also known as
dimethyldiallylammonium chloride, (meth)acrylamidopropyl
trimethylammonium chloride, 2-(meth)acryloyloxy ethyl trimethyl
ammonium chloride, 2-(meth)acryloyloxy ethyl trimethyl ammonium
methyl sulfate, 2-(meth)acryloyloxyethyltrimethyl ammonium
chloride, N,N-Dimethylaminoethyl(meth)acrylate methyl chloride
quaternary, methacryloyloxy ethyl betaine as well as other betaines
and sulfobetaines, 2-(meth)acryloyloxy ethyl dimethyl ammonium
hydrochloride, 3-(meth)acryloyloxy ethyl dimethyl ammonium
hydroacetate, 2-(meth)acryloyloxy ethyl dimethyl cetyl ammonium
chloride, 2-(meth)acryloyloxy ethyl diphenyl ammonium chloride and
others.
[0051] As used herein, the term "nonionic ethylenically unsaturated
monomer" means an ethylenically unsaturated monomer which does not
introduce a charge in to the non-anionic hybrid mixture. These
nonionic ethylenically unsaturated monomers include, but are not
limited to, acrylamide, methacrylamide, N alkyl(meth)acrylamide,
N,N dialkyl(meth)acrylamide such as N,N dimethylacrylamide,
hydroxyalkyl(meth)acrylates, alkyl(meth)acrylates such as
methylacrylate and methylmethacrylate, vinyl acetate, vinyl
morpholine, vinyl pyrrolidone, vinyl caprolactam, vinyl formamide,
vinyl acetamide, ethoxylated alkyl, alkaryl or aryl monomers such
as methoxypolyethylene glycol(meth)acrylate, allyl glycidyl ether,
allyl alcohol, glycerol(meth)acrylate, monomers containing silane,
silanol and siloxane functionalities and others. The nonionic
ethylenically unsaturated monomer is preferably water soluble. The
preferred nonionic ethylenically unsaturated monomers are
acrylamide, methacrylamide, N methyl(meth)acrylamide, N,N
dimethyl(meth)acrylamide, vinyl pyrrolidone, vinyl formamide, vinyl
acetamide and vinyl caprolactam.
[0052] The cationic or non-ionic hybrid mixture has a naturally
derived hydroxyl containing chain transfer agent. The chain
transfer agent is preferably present from about 0.1% by weight to
about 98%, more preferably from about 10 to about 95% and most
preferably from about 20 to about 75% by weight, based on the total
weight of the cationic or non-ionic hybrid copolymer composition.
In another embodiment, the chain transfer agent is preferably
present from about 40% to about 60% by weight. In an embodiment,
the chain transfer agent may be the terminating moiety, or end
group of the polymeric chain comprised of the ethylenically
unsaturated monomer.
[0053] Hybrid mixtures useful in gas hydrate inhibitor compositions
include both anionic and non-anionic intimate mixtures and/or
hybrid copolymer compositions. In an embodiment, a gas hydrate
inhibitor composition includes at least one nonionic ethylenically
unsaturated monomer which is a vinyl lactam or vinyl lactam with a
co-monomer, such as a non-anionionic co-monomer. In a further
embodiment, the at least one nonionic ethylenically unsaturated
monomer is N-vinyl pyrrolidone or vinyl caprolactam or combinations
thereof. In an embodiment, the nonionic ethylenically unsaturated
monomer is -a combination of vinyl pyrrolidone or vinyl caprolactam
present in a ratio in a range of from about 25:75 to about 75:25
vinyl pyrrolidone to vinyl caprolactam.
[0054] In yet another embodiment, the gas hydrate inhibitor
composition includes a naturally derived hydroxyl containing chain
transfer agent which is a polysaccharide. In a further embodiment,
the polysaccharide can be hydrolyzed starch having a DE of greater
than 5. In an even further embodiment, the polysaccharide is
maltodextrin having a DE greater than 5. In an embodiment of the
invention, the maltodextrin has a DE of 10 or greater.
[0055] In a further embodiment, the naturally derived hydroxyl
containing chain transfer agent comprises maltodextrin or corn
syrup solids. In an embodiment of the invention, the maltodextrin
or corn syrup solids, preferably has a dextrose equivalent (DE) of
greater than 5. In another embodiment, the maltodextrin or corn
syrup solids has a DE of 10 or greater. The term dextrose
equivalent, as used herein, is a measure of the amount of reducing
sugars present in a sugar product, relative to glucose, and is a
well known term of art.
[0056] In another embodiment, the hybrid copolymer composition
and/or intimate mixture is made in the presence of a hybrid
initiator. "Hybrid initiators", for purposes of this invention,
include free radical initiators, initiating systems excluding metal
ion based initiators or metal ion-based initiators.
[0057] In an embodiment, the hybrid initiators are free radical
initiators or initiating systems excluding metal ion based
initiators or initiating systems. The hybrid initiators preferably
are not free radical abstractors but promote chain transfer.
Furthermore, the hybrid initiator is preferably water soluble.
Exemplary hybrid initiators include, but are not limited to,
peroxides, azo initiators as well as redox systems like tert-butyl
hydroperoxide and erythorbic acid, peroxide such as persulfate and
an amine such as hydroxylamine sulfate, persulfate and sodium
formaldehyde sulfoxylate etc. The hybrid initiators may include
both inorganic and organic peroxides. Suitable inorganic peroxides
include sodium persulfate, potassium persulfate and ammonium
persulfate. Azo initiators, such as water soluble azo initiators,
may also be suitable hybrid initiators. Water soluble azo
initiators include, but are not limited to,
2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride,
2,2'-Azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate,
2,2'-Azobis(2-methylpropionamidine)dihydrochloride,
2,2'-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate,
2,2'-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochlori-
de, 2,2'-Azobis[2-(2-imidazolin-2-yl)propane],
2,2'-Azobis(1-imino-1-pyrrolidino-2-ethylpropane)dihydrochloride,
2,2'-Azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethl]propionamide-
}, 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] and the
like.
[0058] In an embodiment, the initiator is a nonionic initiator.
Exemplary hybrid initiators include, but are not limited to,
peroxides, azo initiators as well as redox systems like tert-butyl
hydroperoxide and erythorbic acid, peroxide such as persulfate and
an amine such as hydroxylamine sulfate, persulfate and sodium
formaldehyde sulfoxylate etc. In an embodiment of the invention,
the initiator is an Azo initiator, such as
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] or
2,2'-Azobis(2-methylpropionamidine)dihydrochloride.
[0059] In embodiment, the hybrid mixtures utilized as gas hydrate
inhibitors in accordance with the present invention may be used
either in pure aqueous solution or alternatively in solvent
mixtures, such as in water/alcohol mixtures. A suitable solvent may
include ethylene glycol. In another embodiment, the hybrid mixtures
may be made into powders by removing the solvent and drying.
Accordingly, the hybrid mixtures may be redispersed or redissolved
by introducing the powdered mixtures into the water-containing
media in which gas hydrate formation occurs. In an embodiment, the
hybrid mixtures are added to the liquid systems, such as mineral
oil mixtures or natural gas mixtures, in an amount which one of
ordinary skill in the art would select based on the particular
application and conditions. In embodiments of the invention, the
hybrid mixtures are hybrid copolymer compositions encompassing both
anionic and non-anionic hybrid copolymer compositions which are
latently-detectable, which means that they will not be detectable
in the visible light range until the hybrid copolymer composition
is contacted with a photoactivator. As defined herein, the
"photoactivator" is an appropriate reagent or reagents which, when
present in effective amounts, will react with the hybrid copolymer
composition, thereby converting the hybrid copolymer composition
into a chemical species which strongly absorbs in the region from
about 300 to about 800 nanometers when activated with, for example,
sulfuric acid and phenol. In an embodiment of this invention, the
activated hybrid copolymer composition will absorb in the region
from about 400 to about 700 nanometers.
[0060] A latently detectable moiety of this invention will be
formed from a naturally derived hydroxyl containing chain transfer
agent especially when it is saccharide or polysaccharide moiety.
The photoactivator may be the combination of sulfuric acid and
phenol (see Dubois et al, Anal. Chem. 28 (1956) p. 350 and Example
1 of U.S. Pat. No. 5,654,198, which is incorporated in its entirety
by reference herein). Polymers typically tagged with latently
detectable moieties exhibit a drop in efficacy when compared to
polymers without these groups. This is especially true when the
weight percent of the latently detectable moiety is over 10 or 20
percent of the polymer. However, it has been found that the hybrid
copolymers compositions of the present invention perform well even
when containing 50 percent or more of the latently detectable
moiety. Thus, the advantages of good performance and ready
detectability are provided, which allow monitoring the system and
controlling scale without over dosing the scale control
polymer.
[0061] In further embodiments of the present invention, the
ethylenically unsaturated monomer of the hybrid mixture may
optionally be selected from at least one ester monomer.
[0062] Exemplary ester monomers include, but are not limited to,
esters derived from dicarboxylic acid as well as hydroxyalkyl
esters. Suitable ester monomers derived from dicarboxylic acid
include, but are not limited to, monomethylmaleate,
dimethylmaleate, monomethylitaconate, dimethylitaconate,
monoethylmaleate, diethylmaleate, monoethylitaconate,
diethylitaconate, monobutylmaleate, dibutylmaleate,
monobutylitaconate and dibutylitaconate. Suitable hydroxyalkyl
esters include, but are not limited to, hydroxy
ethyl(meth)acrylate, hydroxy propyl(meth)acrylate, hydroxy
butyl(meth)acrylate and the like.
[0063] In still yet another aspect, the invention relates to an
"amphoteric hybrid mixture" containing both anionic and cationic
groups. The anionic moieties can be on the natural component with
the cationic moieties on the synthetic component or the cationic
moieties can be on the natural component with the anionic moieties
on the synthetic component or combinations thereof. In an
embodiment, for example when the natural component is a
polysaccharide, the anionic material can be an oxidized starch and
the cationic moiety can be derived from cationic ethylenically
unsaturated monomers such as diallyldimethylammonium chloride.
Alternatively, the oxidized starch itself may first be reacted with
cationic substituent such as
3-chloro-2-hydroxypropyl)trimethylammonium chloride and then
reacted with a synthetic anionic or cationic monomer or mixtures
thereof.
[0064] In another embodiment, a cationic starch may be reacted with
an anionic monomer. Finally, the cationic and anionic moieties may
be on the synthetic component of these polymers. These amphoteric
hybrid copolymer composition containing both anionic and cationic
groups are particularly useful in detergent formulations as
dispersants and cleaning aids. It is understood that these polymers
will contain both a natural component and a synthetic component.
The cationic moieties are preferably present in the range of 0.001
to 40 mole % of the anionic moieties, more preferably the cationic
moieties are present in the range of 0.01 to 20 mole % of the
anionic moieties, and most preferably the cationic moieties are
present in the range of 0.1 to 10 mole % of the anionic
moieties.
[0065] Polymers formed from cationic ethylenically unsaturated
monomers generally tend to have poorer toxicological and
environmental profiles compared to polymers formed from
non-cationic ethylenically unsaturated monomers. Therefore, it may
be necessary to minimize the level of cationic ethylenically
unsaturated monomer used in preparing the amphoteric hybrid
mixture. In an embodiment of the invention, when a cationic
ethylenically unsaturated monomer is used to produce an amphoteric
hybrid mixture, the cationic ethylenically unsaturated monomer is
preferably present up to 10 mole % of the hybrid mixture, more
preferably the cationic ethylenically unsaturated monomer is
preferably present up to 6 mole % of the hybrid mixture, and most
preferably the cationic ethylenically unsaturated monomer is
preferably present up to 5 mole % of the hybrid mixture.
[0066] In still yet another aspect, the invention relates to hybrid
mixtures derived from monomers produced from natural sources such
as acrylamide produced by fermentation. One skilled in the art will
recognize that monomers produced from natural sources increase the
renewable carbon content of the polymers of this invention.
EXAMPLES
[0067] The following examples are intended to exemplify the present
invention but are not intended to limit the scope of the invention
in any way. The breadth and scope of the invention are to be
limited solely by the claims appended hereto.
Synthesis Example 1
Preparation of an N-vinyl pyrrolidone/maltodextrin (DE 9.0-12.0)
Hybrid Mixture by Synthesis Method A
[0068] This is an example of a successful synthesis. The synthetic
component of the hybrid copolymer composition is derived from
N-vinyl pyrrolidone; the naturally occurring portion of the hybrid
copolymer composition is derived from a DE 9.0-12.0 maltodextrin,
which is the naturally derived hydroxyl containing chain transfer
agent. A DE of 9.0-12.0 roughly corresponds to a glucose degree of
polymerization of 10-13, or a number average molecular weight (Mn)
of 1600-2100. The amount of the hybrid copolymer composition
derived from maltodextrin was 50 wt. % (based on dry polymer). A
critical feature of this synthesis is that a maltodextrin with a
DE>5 was used.
Reagents:
Initial Charge:
TABLE-US-00002 [0069] Deionized water 23.5671 g Maltrin M100 (Grain
Processing Corporation; 26.4966 g, Lot# M0910530; 94.41% solids) as
is basis; 25.0154 g, 100% basis N-vinyl pyrrolidone (Aldrich)
6.2436 g 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide]
0.0654 g (Wako VA-086)
Addition Funnel #1:
TABLE-US-00003 [0070]
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.1908 g (Wako
VA-086) Deionized water 55.2253 g
Addition Funnel #2:
TABLE-US-00004 [0071] N-vinyl pyrrolidone (Aldrich) 18.7925 g
Deionized water 36.9796 g
[0072] A four-neck round bottom flask was equipped with a
mechanical stirrer, reflux condenser, a 60 mL addition funnel and a
125 mL addition funnel. The weight of the flask with stirring
apparatus alone was 483.20 g. To the flask were charged 23.5671 g
deionized water and 26.4966 g Maltrin M100 maltodextrin. The
mixture was stirred until a homogeneous solution was obtained.
[0073] To the 60 mL addition funnel was charged a solution of
VA-086 initiator in deionized water (Additional Funnel #1); to the
125 mL addition funnel was charged a solution of N-vinyl
pyrrolidone in deionized water [Addition Funnel #2].
[0074] The reaction was warmed to 95.degree. C. using a
thermostatted oil bath. When the temperature reached about
53.degree. C., 6.2436 g N-vinyl pyrrolidone and 0.0654 g VA-086
were added in one portion and heating was continued. A transient
light pink color was noted after the addition; the mixture remained
clear. When temperature reached 93.degree. C., drop-wise addition
over 2.45 h of the contents of the two addition funnels was
commenced. The rate of addition was fairly uniform although
adjustments to the rate were occasionally necessary to keep the
addition rates even. After the addition was complete, heating at
95.degree. C. was continued for an additional 2.75 h. At the
conclusion of the reaction, the polymer solution was clear.
[0075] After cooling and standing overnight, the polymer solution
was turbid and phase separation appeared to have occurred. The
polymer was diluted in the reaction vessel with a total of 83.3 g
deionized water. A clear, apparently single phase solution was
obtained. The yield of polymer solution measured in the flask was
246.08 g.
[0076] Theoretical solids of the polymer solution (based on the
amount of monomer and maltodextrin added divided by the total yield
of polymer solution): 20.3%. The experimental solids (gravimetric
at 130.degree. C. for 1.5 h, duplicate runs) was 19.9%. This
corresponds to a monomer conversion of 96%.
Synthesis Example 2
Preparation of an N-vinyl pyrrolidone/maltodextrin (DE 9.0-12.0)
Hybrid Mixture by Synthesis Method B
[0077] This is an example of a successful synthesis. The synthetic
component of the hybrid copolymer composition is derived from
N-vinyl pyrrolidone; the naturally occurring portion of the hybrid
copolymer composition is derived from a DE 9.0-12.0 maltodextrin,
which is the naturally derived hydroxyl containing chain transfer
agent. A DE of 9.0-12.0 roughly corresponds to a glucose degree of
polymerization of 10-13, or a number average molecular weight (Mn)
of 1600-2100. The amount of the hybrid copolymer composition
derived from maltodextrin was 50 wt. % (based on dry polymer). A
critical feature of this synthesis is that a maltodextrin with a
DE>5 was used.
Reagents:
Initial Charge:
TABLE-US-00005 [0078] Deionized water 14.49 g N-vinyl pyrrolidone
(Aldrich) 6.29 g
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.0624 g (Wako
VA-086)
Addition Funnel #1:
TABLE-US-00006 [0079] Maltrin M100 (Grain Processing Corporation;
Lot# M0910530; 26.4923 g, 94.41% solids) as is basis; 25.0114 g,
100% basis 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide]
0.1888 g (Wako VA-086) Deionized water 46.51 g
Addition Funnel #2:
TABLE-US-00007 [0080] N-vinyl pyrrolidone (Aldrich) 18.7547 g
Deionized water 54.5410 g
[0081] A four-neck round bottom flask was equipped with a
mechanical stirrer, reflux condenser, and two 125 mL addition
funnels. The weight of the flask with stirring apparatus alone was
479.19 g. To the flask were charged 14.49 g deionized water, 6.29 g
N-vinyl pyrrolidone, and 0.0624 g Wako VA-086. The mixture was
stirred until a homogeneous solution was obtained.
[0082] To the first 125 mL addition funnel was charged a solution
of 0.1888 g VA-086 initiator and 26.4923 g Maltrin M100 in 46.51 g
deionized water [Additional Funnel #1]; to the second 125 mL
addition funnel was charged a solution of N-vinyl pyrrolidone in
deionized water [Addition Funnel #2].
[0083] The reaction was warmed to 95.degree. C. using a
thermostatted oil bath. When temperature reached 93.degree. C.,
drop-wise addition over 3 h of the contents of the two addition
funnels was commenced. The rate of addition was fairly uniform
although adjustments to the rate were occasionally necessary to
keep the addition rates even. After the addition was complete,
heating at 95.degree. C. was continued for an additional 3 h. At
the conclusion of the reaction, the polymer solution was clear.
[0084] After cooling and standing overnight, the polymer solution
was turbid and phase separation appeared to have occurred. The
polymer was diluted in the reaction vessel with a total of 83.3 g
deionized water. A clear, apparently single phase solution was
obtained. The yield of polymer solution measured in the flask was
249.24 g.
[0085] Theoretical solids of the polymer solution (based on the
amount of monomer and maltodextrin added divided by the total yield
of polymer solution): 20.1%. The experimental solids (gravimetric
at 130.degree. C. for 1.5 h) was 20.1%. This corresponds to a
monomer conversion of essentially 100%.
Synthesis Examples 3-8
Preparation of Additional Non-Ionic Hybrid Mixtures
[0086] Additional hybrid copolymer compositions were prepared by
Synthesis Methods A or B. The compositions are summarized in Table
1 below.
TABLE-US-00008 TABLE 1 Additional hybrid copolymer compositions.
Amount of maltodextrin in final polymer Polymer Synthesis Synthetic
(wt.% of dry concentration in Example Method Maltodextrin used
component polymer) water 3 B Maltrin M100 N-vinyl 35 wt. % 28.9 wt.
% (DE 9.0-12.0) pyrrolidone 4 B Maltrin M100 N-vinyl 65 wt. % 29.7
wt. % (DE 9.0-12.0) pyrrolidone 5 A Maltrin M100 N-vinyl 50 wt. %
36.3 wt. % (DE 9.0-12.0) pyrrolidone (50 wt %) and vinyl
caprolactam (50 wt. %) 6 B Maltrin M150 N-vinyl 50 wt. % 25.1 wt. %
(DE 13.0-17.0) pyrrolidone 7 A Maltrin M100 N-vinyl 90 wt. % 29.9
wt. % (9.0-12.0) pyrrolidone 8 A Maltrin M150 N-vinyl 50 wt. % 28.7
wt. % (DE 13.0-17.0)) pyrrolidone( 75 wt. %), methacrylamide (20
wt. %); and vinyl imidazole (5 wt. %)
[0087] All of the resulting polymers were clear in solution at the
listed concentration in water. The polymer solutions were preserved
by the addition of 0.5-0.75 wt % Glydant Plus.
Synthesis Example 9
Preparation of an N-vinyl pyrrolidone/maltodextrin (DE 9.0-12.0)
Hybrid Mixture by Synthesis Method C
[0088] This is an example of a successful synthesis. The synthetic
component of the hybrid copolymer composition is derived from
N-vinyl pyrrolidone; the naturally occurring portion of the hybrid
copolymer composition is derived from a DE 9.0-12.0 maltodextrin,
which is the naturally derived hydroxyl containing chain transfer
agent. A DE of 9.0-12.0 roughly corresponds to a glucose degree of
polymerization of 10-13, or a number average molecular weight (Mn)
of 1600-2100. The amount of the hybrid copolymer composition
derived from maltodextrin was 50 wt. % (based on dry polymer). A
critical feature of this synthesis is that a maltodextrin with a
DE>5 was used.
Reagents:
Initial Charge:
TABLE-US-00009 [0089] Deionized water 288.75 g Maltrin M100 (DE
9.0-12.0; Grain Processing Corporation; 66.45 g, 94.05% solids) as
is basis; 62.50 g, 100% basis N-vinyl pyrrolidone (Aldrich) 62.5 g
2,2'-Azobisisobutyronitrile (Vazo 64; DuPont) 0.63 g
[0090] 1 L four-neck round bottom reaction flask was equipped with
a 23/4'' S-S mechanical stirrer/overhead mixer motor, thermometer
and nitrogen inlet topped reflux condenser. To the flask was
charged 62.5 g N-vinyl pyrrolidone and 0.63 g Vazo-64 initiator.
The resulting solution was purged with with nitrogen at ambient
temperature for about 15 minutes.
[0091] To a 600 mL beaker, was add 288.75 g water and 66.45 g
Maltrin M100 (Maltodextrin DE=9 to 12; 94.05% solids). The
resulting mixture was stirred until the maltodextrin dissolved, and
then the clear maltodextrin solution was transferred to a 500 mL
addition funnel. The addition funnel was set up on reactor, and a
sub-surface nitrogen purge was applied to the solution in the
addition funnel at ambient temperature for about 15 minutes.
[0092] The maltodextrin solution was added rapidly to the reaction
flask monomer/initiator in reactor. Heating of the reaction mixture
was then begun using a water bath (hot-plate controlled by
Thermo-watch controlled via bath thermometer). The reaction
temperature was brought to 70.+-.1.degree. C..degree. under a
positive pressure of nitrogen. A.apprxeq.3.degree. C. exotherm was
noted during the initial 3/4 Hr of reaction, after which the
reaction and bath temperatures became almost equal.
[0093] The reaction was held at 70.degree. C. for a total of 10 h
(over two days). At the conclusion of the polymerization, the
reaction was cooled to ambient temperature with a cold water bath,
the amount of water that was found to be lost (2.18 g) was
replenished.
[0094] The polymer solution as prepared was not transparent. The
polymer solution was diluted from 30.3% solids (in theory) to 20%
solids (in theory by the addition of water, but the solution was
still not clear. Further dilution to a theoretical polymer
concentration of 18 wt. % resulted in an essentially transparent
solution. A total of 279.58g extra water was needed to dilute the
polymer.
[0095] The yield of polymer solution was 697.9 g. The experimental
solids was 17.9%. This corresponds to a monomer conversion of 99.4.
The final product was preserved by the addition of 0.75 wt %
Glydant Plus on total solution weight; final polymer solution
solids were 18.47%.
Synthesis Example 10
Synthesis of Non-Ionic Hybrid Mixture with Polysaccharide Chain
Transfer Agent
[0096] 50 grams of maltodextrin as a polysaccharide chain transfer
agent (STAR-DRI 180 DE 18 spray-dried maltodextrin available from
Tate and Lyle, Decatur, Ill.) was dissolved in 150 grams of water
in a reactor and heated to 75.degree. C. A monomer solution
containing 50 grams of hydroxyethylacrylate was subsequently added
to the reactor over a period of 50 minutes. An initiator solution
comprising of 2 grams of V-50 [2,2'-Azobis(2
amidino-propane)dihydrochloride azo initiator from Wako Pure
Chemical Industries, Ltd., Richmond, Va.] in 30 grams of water was
added to the reactor at the same time as the monomer solution over
a period of 60 minutes. The reaction product was held at 75.degree.
C. for an additional 60 minutes. The final product was a clear
almost water white solution.
Synthesis Example 11
Synthesis of Non-Anionic Hybrid Mixture
[0097] 150 grams of maltodextrin as a polysaccharide chain transfer
agent (Cargill MD.TM. 01918 dextrin, spray-dried maltodextrin
obtained by enzymatic conversion of common corn starch, available
from Cargill Inc., Cedar Rapids, Iowa) was initially dissolved in
200 grams of water in a reactor and 70 g of HCl (37%) was added and
heated to 98.degree. C. A monomer solution containing 109 grams of
dimethyl aminoethyl methacrylate dissolved in 160 grams of water
was subsequently added to the reactor over a period of 90 minutes.
An initiator solution comprising of 6.6 grams of sodium persulfate
in 40 grams of water was added to the reactor at the same time as
the monomer solution over a period of 90 minutes. The reaction
product was held at 98.degree. C. for an additional 60 minutes. The
reaction product was then neutralized by adding 14 grams of a 50%
solution of NaOH and the final product was an amber colored
solution.
Synthesis Example 12
Synthesis of Non-Anionic Hybrid Mixture
[0098] 35 grams of Amioca Starch was dispersed in 88 grams of water
in a reactor and heated to 52. The starch was depolymerized by
addition of 1.07 grams of concentrated sulfuric acid (98%). The
suspension was held at 52.degree. C. for 1.5 hours. The reaction
was then neutralized with 1.84 grams of 50% NaOH solution and the
temperature was raised to 90.degree. C. for 15 minutes. The starch
gelatinizes and the viscosity increased during the process and a
gel is formed. The viscosity dropped after the gelatinization was
completed. The temperature was lowered to 72 to 75.degree. C. A
solution of 80.7 grams of dimethyl diallyl ammonium chloride (62%
in water) was added to the reactor over a period of 30 minutes. An
initiator solution comprising of 0.2 grams of sodium persulfate in
20 grams of water was added to the reactor at the same time as the
monomer solution over a period of 35 minutes. The reaction product
was held at 98.degree. C. for an additional 2 hours. The final
product was a slightly opaque yellow colored solution.
Synthesis Example 13
Synthesis of Non-Anionic Hybrid Mixture
[0099] 35 grams of Amioca Starch was dispersed in 88 grams of water
in a reactor and heated to 52. The starch was depolymerized by
addition of 0.52 grams of concentrated sulfuric acid (98%). This is
half the acid used in Example 32 and causes less depolymerization
of the starch resulting in a higher molecular weight. Thus the
molecular weight of the polysaccharide chain transfer agent can be
controlled. The suspension was held at 52.degree. C. for 1.5 hours.
The reaction was then neutralized with 0.92 grams of 50% NaOH
solution and the temperature was raised to 90.degree. C. for 15
minutes. The starch gelatinizes and the viscosity increased during
the process and a gel was formed. The viscosity dropped after the
gelatinization was completed. The reaction was diluted with 30
grams of water and the temperature was lowered to 72 to 75.degree.
C. A solution of 80.7 grams of dimethyl diallyl ammonium chloride
(62% in water) was added to the reactor over a period of 30
minutes. An initiator solution comprising of 0.2 grams of sodium
persulfate in 20 grams of water was added to the reactor at the
same time as the monomer solution over a period of 35 minutes. The
reaction product was held at 98.degree. C. for an additional 2
hours. The final product was a clear light yellow colored
solution.
Synthesis Example 14
Synthesis of Hybrid Mixture with Polysaccharide (Inulin) Chain
Transfer Agent
[0100] 50 grams of a polysaccharide chain transfer agent
(DEQUEST.RTM. PB11620 carboxymethyl inulin 20% solution available
from Thermphos) was dissolved in 150 grams of water in a reactor
and heated to 75.degree. C. A monomer solution containing 50 grams
of N,N dimethyl acrylamide was subsequently added to the reactor
over a period of 50 minutes. An initiator solution comprising of 2
grams of V-50 [2,2'-azobis(2-amidinopropane)dihydrochloride]azo
initiator from Wako Pure Chemical Industries, Ltd., Richmond, Va.]
in 30 grams of water was added to the reactor at the same time as
the monomer solution over a period of 60 minutes. The reaction
product was held at 75.degree. C. for an additional 60 minutes. The
reaction product was diluted with 140 grams of water and the final
product was a clear homogenous amber colored solution.
Synthesis Example 15
Synthesis of Hybrid Mixture with Polysaccharide (Cellulosic) Chain
Transfer Agent
[0101] Carboxymethyl cellulose (AQUALON.RTM. CMC 9M3ICT available
from Hercules, Inc., Wilmington, Del.) was depolymerized in the
following manner. Thirty grams of AQUALON.RTM. CMC was introduced
in to 270 g of deionized water with stirring. 0.03 g of Ferrous
ammonium sulfate hexahydrate and 2 g of hydrogen peroxide
(H.sub.2O.sub.2) solution (35% active) was added. The mixture was
heated to 60.degree. C. and held at that temperature for 30
minutes. This depolymerized CMC solution was then heated to
90.degree. C.
[0102] A monomer solution containing 50 grams of acrylamide (50%
solution) is subsequently added to the reactor over a period of 50
minutes. An initiator solution comprising of 2 grams of V-086
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide]azo initiator
from Wako Pure Chemical Industries, Ltd., Richmond, Va.] in 30
grams of water is added to the reactor at the same time as the
monomer solution over a period of 60 minutes. The reaction product
is held at 90.degree. C. for an additional 60 minutes.
Synthesis Example 16
Synthesis of a Non-Anionic Hybrid Mixture Containing a Quaternary
Amine Monomer and a Cationic Polysaccharide Functionality
[0103] 40 grams of Nsight C-1 as a cationic starch chain transfer
agent (available from AkzoNobel, Bridgewater N.J.) was initially
dissolved in 100 grams of water in a reactor and heated to
98.degree. C. A solution of 38.7 grams of dimethyl diallyl ammonium
chloride (62% in water) was subsequently added to the reactor over
a period of 45 minutes. An initiator solution comprising of 3.3
grams of sodium persulfate in 20 grams of water was added to the
reactor at the same time as the monomer solution over a period of
45 minutes. The reaction product was held at 98.degree. C. for an
additional 60 minutes. The final product was a clear amber colored
solution.
Synthesis Example 17
Synthesis of Non-Anionic Hybrid Mixture
[0104] 35 grams of Hylon VII Starch (a high amylose starch
containing 70% amylose) was dispersed in 132 grams of water in a
reactor and heated to 52.degree. C. The starch was depolymerized by
addition of 1.07 grams of concentrated sulfuric acid (98%). The
suspension was held at 52.degree. C. for 1.5 hours. The reaction
was then neutralized with 1.84 grams of 50% NaOH solution and the
temperature was raised to 90.degree. C. for 15 minutes. The starch
gelatinizes and the viscosity increased during the process and a
gel was formed. The viscosity dropped after the gelatinization was
completed. The reaction was diluted with 30 grams of water and the
temperature was lowered to 72 to 75.degree. C. A solution of 100.1
grams of [3-(methacryloylamino)propyl]-trimethylammonium chloride
(50% in water) was added to the reactor over a period of 30
minutes. An initiator solution comprising of 0.2 grams of sodium
persulfate in 20 grams of water was added to the reactor at the
same time as the monomer solution over a period of 35 minutes. The
reaction product was held at 98.degree. C. for an additional 2
hours. The final product was an opaque white homogenous
solution.
Synthesis Example 18
Synthesis of Non-Anionic Hybrid Mixture
[0105] 35 grams of Amioca Starch was dispersed in 88 grams of water
in a reactor and heated to 52. The starch was depolymerized by
addition of 0.52 grams of concentrated sulfuric acid (98%). This is
half the acid used in Example 41 and causes less depolymerization
of the starch resulting in a higher molecular weight. Thus the
molecular weight of the polysaccharide chain transfer agent can be
controlled. The suspension was held at 52.degree. C. for 1.5 hours.
The reaction was then neutralized with 0.92 grams of 50% NaOH
solution and the temperature was raised to 90.degree. C. for 15
minutes. The starch gelatinizes and the viscosity increased during
the process and a gel was formed. The viscosity dropped after the
gelatinization was completed. The reaction was diluted with 30
grams of water and the temperature was lowered to 72 to 75.degree.
C. A solution of 66.71 g [2-(methacryloxy)ethyl]-trimethylammonium
chloride (75% in water) was added to the reactor over a period of
30 minutes. An initiator solution comprising of 0.2 grams of sodium
persulfate in 20 grams of water was added to the reactor at the
same time as the monomer solution over a period of 35 minutes. The
reaction product was held at 98.degree. C. for an additional 2
hours. The final product was a homogeneous opaque white paste.
Synthesis Example 19
Synthesis of Non-Ionic Hybrid Mixture with Polysaccharide Chain
Transfer Agent
[0106] Hydroxyethyl cellulose (QP 300 available from Dow) was
depolymerized in the following manner. Thirty grams of QP 300 was
introduced in to 270 g of deionized water with stirring. 0.05 g of
Ferrous ammonium sulfate hexahydrate and 1 g of hydrogen peroxide
(H.sub.2O.sub.2) solution (35% active) was added. The mixture was
heated to 60.degree. C. and held at that temperature for 30
minutes. This depolymerized CMC solution was then heated to
90.degree. C.
[0107] A solution of 38.7 grams of dimethyl diallyl ammonium
chloride (62% in water) is subsequently added to the reactor over a
period of 50 minutes. An initiator solution comprising of 2 grams
of V-086 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide]azo
initiator from Wako Pure Chemical Industries, Ltd., Richmond, Va.]
in 30 grams of water is added to the reactor at the same time as
the monomer solution over a period of 60 minutes. The reaction
product is held at 90.degree. C. for an additional 60 minutes.
Synthesis Example 20
Synthesis of Catanionic Hybrid Mixture Containing Both Anionic and
Cationic Groups
[0108] 150 grams of water was added to 765 grams of RediBond 5330A
(available from National Starch and Chemical) (27% aqueous
solution), and the solution was heated to 40.degree. C. The pH of
the solution was adjusted to pH 7.0 with 50% sodium hydroxide
solution. 0.13 grams of alpha-amylase was added to the solution,
which was allowed to cook for 1 hour. 254.7 grams of this
pre-digested RediBond 5330A as a cationic polysaccharide chain
transfer agent, 2.32 grams of 50% sodium hydroxide solution, and
20.16 grams of monomethyl maleate was heated in a reactor to
87.degree. C. A monomer solution containing 73.88 grams of acrylic
acid and 17.96 grams of water was subsequently added to the reactor
over a period of 4.5 hours. An initiator solution comprised of
13.84 grams of erythorbic acid dissolved in 100 grams of water, and
a second initiator solution comprised of 13.98 grams of tert-butyl
hydrogen peroxide were added to the reactor at the same time as the
monomer solution over a period of 5 hours. The reaction product was
cooled and held at 65.degree. C. for an additional 60 minutes. The
final product was a brown solution.
Synthesis Example 21
Synthesis of an Ester Hybrid Mixture
[0109] 45.9 grams of monomethylmaleate (ester monomer) was
dissolved in 388 grams of water. 15.3 grams of ammonium hydroxide
was added and the mixture was heated to 87 C. 85 grams of
maltodextrin of DE 18(Cargill MD.TM. 01918, spray-dried
maltodextrin obtained by enzymatic conversion of common corn
starch, available from Cargill Inc., Cedar Rapids, Iowa) was added
just before the monomer and initiator feeds were started. A monomer
solution containing a mixture of 168 grams of acrylic acid and 41.0
grams of hydroxyethyl methacrylate (ester monomer) was added to the
reactor over a period of 5 hours. A first initiator solution
comprising of 21 grams of erythorbic acid dissolved in 99 grams of
water was added over a period of 5.5 hours. A second initiator
solution comprising of 21 grams of a 70% solution of tertiary butyl
hydroperoxide dissolved in 109 grams of water was added over a
period of 5.5 hours. The reaction product was held at 87.degree. C.
for 30 minutes. The final product was a clear light amber solution
and had 34.1% solids.
Synthesis Example 22
Preparation of an N-vinyl pyrrolidone/maltodextrin (DE 13.0-17.0)
Hybrid Mixture
[0110] The synthetic component of the hybrid copolymer composition
is derived from N-vinyl pyrrolidone; the naturally occurring
portion of the hybrid copolymer composition is derived from a DE
13.0-17.0 maltodextrin, which is the naturally derived hydroxyl
containing chain transfer agent. A DE of 13.0-17.0 roughly
corresponds to a glucose degree of polymerization of 7-9, or a
number average molecular weight (Mn) of 1100-1500. The amount of
the hybrid copolymer composition derived from maltodextrin was 50
wt. % (based on dry polymer). A maltodextrin with a DE>5 was
used.
Reagents:
Flask:
TABLE-US-00010 [0111] Deionized water 57.12 g Maltrin M150 (Grain
Processing 63.76 g, as is basis; Corporation; Lot# M0905132; 60.03
g, 100% basis 94.15% solids)
Addition Funnel:
TABLE-US-00011 [0112] N-vinyl pyrrolidone (Aldrich) 60.01 g
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.6046 g (Wako
VA-086) Deionized water 135.07 g
[0113] A four-neck 1000 mL round bottom flask was equipped with a
mechanical stirrer, reflux condenser, a 250 mL addition funnel, and
a stopper. To the flask were charged 57.12 g deionized water and
63.76 g Maltrin M150 maltodextrin. The mixture was stirred until a
homogeneous solution was obtained. To the 250 mL addition funnel
was charged a solution of 60.01 g N-vinyl pyrrolidone and 0.6046 g
VA-086 in deionized water.
[0114] The reaction was warmed to 80.degree. C. using an oil bath
and 1/4 of the contents of the addition funnel were added at once.
Heating was continued, and when the temperature reached 95.degree.
C., drop-wise addition at a uniform rate over 3 h. of the contents
of the addition funnel was commenced. After the addition was
complete, heating at 95.degree. C. was continued for an additional
2.75 h. At the conclusion of the reaction, the polymer solution was
clear with some viscosity build.
[0115] After cooling and standing overnight, the polymer solution
was turbid and phase separation appeared to have occurred. The
reaction mixture was then heated for 1 h. at >95.degree. C. and
then diluted in the reaction vessel with a total of 88.62 g
deionized water. A clear, apparently single phase solution was
obtained. The yield of polymer solution measured in the flask was
400.0 g. The experimental solids (gravimetric at 130.degree. C. for
1.5 h, duplicate runs) was 30.4%.
[0116] The polymer was preserved by the addition of 0.75 wt. %
Glydant Plus.
Synthesis Example 23
Preparation of an N-vinyl pyrrolidone-co-vinyl
caprolactam/maltodextrin (DE 13.0-17.0) Hybrid Mixture
[0117] The synthetic component of the hybrid copolymer composition
is derived from a combination of N-vinyl pyrrolidone and vinyl
caprolactam; the naturally occurring portion of the hybrid
copolymer composition is derived from a DE 13.0-17.0 maltodextrin,
which is the naturally derived hydroxyl containing chain transfer
agent. A DE of 13.0-17.0 roughly corresponds to a glucose degree of
polymerization of 7-9, or a number average molecular weight (Mn) of
1100-1500. The amount of the hybrid copolymer composition derived
from maltodextrin was 50 wt. % (based on dry polymer). A
maltodextrin with a DE>5 was used.
Reagents:
Flask:
TABLE-US-00012 [0118] Deionized water 56.48 g Maltrin M150 (Grain
Processing 63.72 g, as is basis; Corporation; Lot# M0905132; 59.99
g, 100% basis 94.15% solids)
Addition Funnel #1:
TABLE-US-00013 [0119] N-vinyl pyrrolidone (Aldrich) 30.05 g N-vinyl
caprolactam (Aldrich) 30.41 g
Addition Funnel #2:
TABLE-US-00014 [0120] Deionized water 135.00 g
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.6085 g (Wako
VA-086)
[0121] A four-neck round 1000 mL bottom flask was equipped with a
mechanical stirrer, reflux condenser, 125 mL addition funnel, and a
250 mL addition funnel. To the flask were charged 56.48 g deionized
water and 63.72 g maltodextrin Maltrin M150 (DE 13.0-17.0). The
mixture was stirred with gentle heating until a homogeneous
solution was obtained.
[0122] Addition Funnel #1 was charged with a mixture of 30.05 g
N-vinyl pyrrolidone and 30.41 g N-vinyl caprolactam (homogeneous
solution). Addition Funnel #2 was charged with a solution of 0.6085
g 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (Wako
VA-086) in 135.00 g deionized water.
[0123] The reaction was warmed to about 75.degree. C. using a
thermostatted oil bath. At this point, 1/4 of the contents of each
addition funnel was added at once. The solution in the flask became
cloudy--it was no longer homogeneous. Heating of the reaction
vessel was continued, and when the reaction temperature reached
96.degree. C., drop-wise addition of the contents of the two
addition funnels over a period of 3 h. was commenced. The rate of
addition was fairly uniform although adjustments to the rate were
occasionally necessary to stay on target for a 3 h. addition time;
the reaction temperature was maintained at 96-99.degree. C.
throughout the polymerization. The reaction mixture remained cloudy
throughout the polymerization, and there appeared to be a formation
of distinct phases. After the addition was complete, heating was
continued for an additional 0.5 h. At the conclusion of the
reaction, the polymer solution was cloudy.
[0124] After cooling and standing overnight, the polymer solution
had become clear and apparently homogeneous, and it was somewhat
viscous. The reaction mixture was heated to 95-100.degree. C. for
an additional 3.5 h. On heating, the reaction mixture again became
cloudy. On cooling, the reaction mixture clarified. The temperature
at which the mixture clarified was about 68.degree. C. To the clear
reaction mixture was then added 10.05 g deionized water. A clear,
apparently single phase solution was obtained. The yield of polymer
solution measured in the flask was 316.18 g. The experimental
solids (gravimetric at 130.degree. C. for 1.5 h; average of two
runs) was 37.8%. This corresponds to a monomer conversion of about
98%.
[0125] The polymer solution was preserved by the addition of 0.75
wt. % Glydant Plus.
[0126] Cloud point at 1 wt. % in water (heating rate
.about.2.degree. C./minute): 77.degree. C.
Synthesis Example 24
Preparation of an N-vinyl pyrrolidone-co-vinyl
caprolactam/maltodextrin (DE 13.0-17.0) Hybrid Mixture
[0127] The synthetic component of the hybrid copolymer composition
is derived from a combination of N-vinyl pyrrolidone and vinyl
caprolactam; the naturally occurring portion of the hybrid
copolymer composition is derived from a DE 13.0-17.0 maltodextrin,
which is the naturally derived hydroxyl containing chain transfer
agent. A DE of 13.0-17.0 roughly corresponds to a glucose degree of
polymerization of 7-9, or a number average molecular weight (Mn) of
1100-1500. The amount of the hybrid copolymer composition derived
from maltodextrin was 50 wt % (based on dry polymer). A
maltodextrin with a DE>5 was used.
Reagents:
Flask:
TABLE-US-00015 [0128] Deionized water 56.24 g Maltrin M150 (Grain
Processing 63.75 g, as is basis; Corporation; Lot# M0905132; 60.02
g, 100% basis 94.15% solids)
Addition Funnel #1:
TABLE-US-00016 [0129] N-vinyl pyrrolidinone (Aldrich) 33.0594 g
N-vinyl caprolactam (Aldrich) 33.0421 g Combined Monomer Mixture
66.1015 g Added to reaction: 60.22 g
Addition Funnel #2:
TABLE-US-00017 [0130] Deionized water 135.03 g
2,2'-Azobis(2-methylpropionamidine)dihydrochloride 0.6130 g (Wako
V-50)
[0131] A four-neck round 1000 mL bottom flask was equipped with a
mechanical stirrer, a nitrogen inlet topped reflux condenser, 125
mL addition funnel, and a 250 mL addition funnel. To the flask were
charged 56.24 g deionized water and 63.75 g maltodextrin Maltrin
M150 (DE 13.0-17.0). The mixture was stirred with gentle heating
until a homogeneous solution was obtained.
[0132] Addition Funnel #1 was charged with 60.22 g of a 50/50 (w/w)
mixture of N-vinyl pyrrolidinone and N-vinyl caprolactam
(homogeneous solution). Addition Funnel #2 was charged with a
solution of 0.6130 g
2,2'-Azobis(2-methylpropionamidine)dihydrochloride (Wako V-50) in
135.03 g deionized water.
[0133] The contents of the flask, Addition funnel #1, and Addition
Funnel #2 were deoxygenated by sub-surface purging with nitrogen
for 15, 5, and 5 minutes, respectively.
[0134] The reaction was warmed to about 70.degree. C. using a
thermostatted oil. At this point, 1/4 of the contents of each
addition funnel was added at once. The solution in the flask became
hazy--it was no longer homogeneous. Drop-wise addition of the
contents of the two addition funnels over a period of 3 h. was then
commenced. The rate of addition was fairly uniform although
adjustments to the rate were occasionally necessary to stay on
target for a 3 h. addition time. The reaction temperature was
maintained at 65-71.degree. C. throughout the polymerization, and
the polymerization was kept under a positive pressure of nitrogen
throughout. The reaction mixture remained cloudy throughout the
polymerization, and there appeared to be a formation of distinct
phases. After the addition was complete, heating was continued for
an additional 3 h. At the conclusion of the reaction, the polymer
solution was frothy, white (cloudy), and viscous.
[0135] After cooling and standing overnight, the polymer solution
had clarified significantly, but it was still slightly turbid. The
reaction was diluted to 400 g total by the addition of 90.9 g
deionized water, but it did not fully clear. An additional 75.27 g
deionized water was added; the reaction was nearly clear at this
point and apparently homogeneous. The yield of polymer solution
measured in the flask was 475.27 g. The experimental solids
(gravimetric at 130.degree. C. for 1.5 h; average of two runs) was
24.9%.
[0136] The polymer solution was preserved by the addition of 0.57
wt. % Glydant (solid).
[0137] Cloud point at 1 wt. % in water (heating rate
.about.2.degree. C./minute) was 58.degree. C.
Synthesis Example 25
Preparation of vinyl caprolactam/maltodextrin (DE 13.0-17.0) Hybrid
Mixture
[0138] The synthetic component of the hybrid copolymer composition
is derived from vinyl caprolactam; the naturally occurring portion
of the hybrid copolymer composition is derived from a DE 13.0-17.0
maltodextrin, which is the naturally derived hydroxyl containing
chain transfer agent. A DE of 13.0-17.0 roughly corresponds to a
glucose degree of polymerization of 7-9, or a number average
molecular weight (Mn) of 1100-1500. The amount of the hybrid
copolymer composition derived from maltodextrin was 50 wt. % (based
on dry polymer). A maltodextrin with a DE>5 was used.
[0139] The polymer was prepared according to the method described
in Synthesis Example 22 with the following exceptions.
4,4'-Azobis(4-cyanovaleric acid), 0.5 parts per hundred parts
monomer and maltodextrin combined(pphm), neutralized to pH 7 with
sodium hydroxide, was used as the initiator, and the reaction was
post-treated with 0.2 pphm 4,4'-Azobis(4-cyanovaleric acid),
neutralized to pH 7 with sodium hydroxide for 5 h at reflux after
dilution of polymer solids to 20 wt. %. The yield of homogenous
polymer solution was 703.4 g. The solids were 19.1%.
Synthesis Example 26
Preparation of vinyl caprolactam/glucose Hybrid Copolymer
[0140] The synthetic component of the hybrid copolymer composition
is derived from vinyl caprolactam N-vinyl pyrrolidone; the
naturally occurring portion of the hybrid copolymer composition is
derived from glucose, which is the naturally derived hydroxyl
containing chain transfer agent.
[0141] The polymer is prepared according to the method described in
Synthesis Example 22.
Synthesis Example 27
Preparation of vinyl caprolactam/lactose Hybrid Copolymer
[0142] The synthetic component of the hybrid copolymer composition
is derived from vinyl caprolactam N-vinyl pyrrolidone; the
naturally occurring portion of the hybrid copolymer composition is
derived from lactose, which is the naturally derived hydroxyl
containing chain transfer agent.
[0143] The polymer is prepared according to the method described in
Synthesis Example 22.
Comparative Synthesis Example 1
Attempted Preparation of an N-vinyl pyrrolidone/maltodextrin (DE
4.0-7.0) Hybrid Mixture
[0144] The synthetic component of the hybrid copolymer composition
is derived from N-vinyl pyrrolidone; the naturally occurring
portion of the hybrid copolymer composition is derived from a DE
4.0-7.0maltodextrin, which is the naturally derived hydroxyl
containing chain transfer agent. A DE of 4.0-7.0 roughly
corresponds to a glucose degree of polymerization of 17 to 30, or a
number average molecular weight (Mn) of 2800 to 4900. The amount of
the hybrid copolymer composition derived from maltodextrin was 50
wt. % (based on dry polymer). A maltodextrin with a DE of about 5
was used.
Reagents:
Initial Charge:
TABLE-US-00018 [0145] Deionized water 57.12 g Maltrin M040, (DE 4.0
- 7.0 maltodextrin; 26.3804 g, as is basis; Grain Processing
Corporation; 94.77% solids) 25.0007 g, 100% basis N-vinyl
pyrrolidone (Aldrich) 6.3053 g 2,2'-Azobis[2-methyl-N-(2- 0.0645 g
hydroxyethyl)propionamide] (Wako VA-086)
Addition Funnel #1:
TABLE-US-00019 [0146]
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.1934 g (Wako
VA-086) Deionized water 38.9322 g
Addition Funnel #2:
TABLE-US-00020 [0147] N-vinyl pyrrolidone (Aldrich) 18.7595 g
Deionized water 19.8633 g
[0148] A four-neck round bottom flask was equipped with a
mechanical stirrer, reflux condenser, a 60 mL addition funnel and a
125 mL addition funnel. The weight of the flask with stirring
apparatus alone was 467.74 g. To the flask were charged 57.12 g of
deionized water and 26.3804 g Maltrin M040. The resulting mixture
was heated using a thermostatted oil bath to .about.90.degree. C.
at which point the maltodextrin slowly dissolved to give a clear,
slightly viscous solution.
[0149] To the 60 mL addition funnel was charged a solution of
0.1934 g VA-086 initiator in 38.9322 g deionized water [Additional
Funnel #1]; to the 125 mL addition funnel was charged a solution of
18.7595 g N-vinyl pyrrolidone in 19.8633 g deionized water
[Addition Funnel #2].
[0150] At this point, 6.3053 g N-vinyl pyrrolidone and 0.0645 g
Wako VA-086 plus a few mL of deionized water rinses were charged to
the reaction mixture and heating was continued. When the reaction
temperature reached 93.degree. C., drop-wise addition over 2.5 h of
the contents of the two addition funnels was commenced. The rate of
addition was fairly uniform although adjustments to the rate were
occasionally necessary to keep the addition rates even. The
reaction was kept at 95.+-.2.degree. C. for the duration of the
addition. Some turbidity was noted towards the end of the
monomer/initiator addition. After the addition was complete,
heating at 95.degree. C. was continued for an additional 3.25 h. At
the conclusion of the reaction, the polymer solution was turbid at
95.degree. C.
[0151] Significant phase separation was noted after the
polymerization reaction had been allowed to stand overnight; the
reaction mixture was white and cloudy. The reaction mixture was
heated to about 90.degree. C. for about 20 minutes; at about
76.degree. C., the mixture became translucent. The reaction was
diluted with 83.52 g water at elevated temperature and then allowed
to cool down. A clear solution was never obtained. Yield of polymer
solution measured in the flask: 250.01 g.
[0152] Dilution of a small amount of the homogenized mixture to 10%
solids failed to give a clear solution.
[0153] Theoretical solids of the polymer solution (based on the
amount of monomer and maltodextrin added divided by the total yield
of polymer solution): 20.0%. The experimental solids (gravimetric
at 130.degree. C. for 1.5 h) was 20.0%. This corresponds to a
monomer conversion of essentially 100%.
[0154] On standing for several days, massive phase separation was
noted.
Comparative Synthesis Example 2
Attempted Preparation of an N-vinyl pyrrolidone/maltodextrin (DE
4.0-7.0) Hybrid Mixture
[0155] The synthetic component of the hybrid copolymer composition
is derived from N-vinyl pyrrolidone; the naturally occurring
portion of the hybrid copolymer composition is derived from a DE
4.0-7.0 maltodextrin, which is the naturally derived hydroxyl
containing chain transfer agent. A DE of 44.0-7.0 roughly
corresponds to a glucose degree of polymerization of 17 to 30, or a
number average molecular weight (Mn) of 2800 to 4900. The amount of
the hybrid copolymer composition derived from maltodextrin was 25
wt. % (based on dry polymer). A maltodextrin with a DE of about 5
was used.
Reagents:
Initial Charge:
TABLE-US-00021 [0156] Deionized water 28.84 g Maltrin M040 (DE 4.0
- 7.0 maltodextrin; 13.1807 g, as is basis; Grain Processing
Corporation; 94.77% solids) 12.4913 g, 100% basis
125 mL Addition Funnel:
TABLE-US-00022 [0157] N-vinyl pyrrolidone (Aldrich) 37.5242 g
2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] 0.3838 g (Wako
VA-086) Deionized water 58.2860 g
[0158] A four-neck round bottom flask was equipped with a
mechanical stirrer, reflux condenser, a 125 mL addition funnel, and
a stopper. The weight of the flask with stirring apparatus alone
was 471.62 g. To the flask were charged 13.1807 g Maltrin M040 (DE
5 maltodextrin) and 28.84 g deionized water. The mixture was heated
to .about.90.degree. C. with stirring until a clear, homogeneous
solution was obtained. The mixture was allowed to cool somewhat
after it became clear, but it did not drop below 50.degree. C.
[0159] To the 125 mL addition funnel was charged a solution of
VA-086 initiator and N-vinyl pyrrolidone in deionized water. The
volume in the addition funnel was 98 mL. To the reaction mixture
was rapidly added 24.5 mL (1/4 of the total volume) of the contents
of the addition funnel.
[0160] The resulting mixture was stirred and warmed to 95.degree.
C. using a thermostatted oil bath. When the temperature reached
93.degree. C., drop-wise addition over 3 h of the contents of the
addition funnels was commenced. The rate of addition was fairly
uniform throughout. During the course of the addition viscosity was
noted to increase, and the reaction mixture gradually changed from
clear to hazy. After the addition was complete, heating at
95.degree. C. was continued for an additional 3 h. One hour after
the addition was complete, 29.17 mL deionized water was added
drop-wise to the reaction via the addition funnel while the
reaction temperature was maintained at 95.degree. C. The
polymerization reaction mixture remained hazy after the addition of
the water. After heating was stopped, the reaction became quite
turbid.
[0161] After cooling and standing overnight, the polymer solution
was opaque, but there was no evidence of phase separation. The
reaction was heated to .about.90.degree. C. and 83.04 g deionized
water was added to further dilute the polymer solution. The polymer
solution did not become clear. The yield of product measured in the
flask was 245.64 g. An additional 4.26 g of deionized water was
added to the reaction vessel. Adjusted yield: 249.9 g.
[0162] Theoretical solids of the polymer solution (based on the
amount of maltodextrin and N-vinyl pyrrolidone added divided by the
total yield of polymer solution): 20.0%. The experimental solids
(gravimetric at 130.degree. C. for 1.5 h, duplicate runs) was
20.4%. This corresponds to a monomer conversion of essentially
100%.
[0163] A small portion of the product was diluted to 10% solids.
This did not clarify the solution.
[0164] Product was preserved by the addition of 0.75 wt. % Glydant
Plus.
[0165] On standing for several days massive phase separation was
noted.
Evaluation of Hybrid Polymers
[0166] A solution of the polymer to be evaluated was prepared at
the desired concentration (based on 100% active polymer) in 50 mL
distilled water. This was charged to a 200 mL jacketed stainless
steel pressure cell equipped with a blade stirrer. The vessel was
pressurized to 77 bar with a synthetic natural gas of the formula
given in Table 1.
TABLE-US-00023 TABLE 1 Synthetic natural gas composition Amount
Component (mole %) Methane 80.67 Ethane 10.20 Propane 4.90
Iso-Butane 1.53 n-Butane 0.76 N.sub.2 0.10 CO.sub.2 1.84
[0167] The temperature of the pressure cell was then lowered from
20.5.degree. C. to 1.degree. C. over 18.97 hours at a constant
cooling rate by circulating cooling/heating fluid through the cell
jacket while stirring at 600 rpm. The actual pressure of the cell
and the temperature were monitored during the cooling. The time and
temperature at which the measured pressure began to deviate from
the expected pressure (as calculated based on the temperature and
initial pressure) were taken to be the gas hydrate formation onset
time and temperature. The rapid hydrate formation time and
temperature were taken to be the point at which the temperature of
the cell contents began to increase due to the exothermic hydrate
formation process. This is illustrated for the hybrid mixture of
Synthesis Example 24, as shown in the FIGURE.
[0168] The Onset Temperature and Time and the Rapid Hydrate
Formation Temperature and Time for the polymers of Synthesis
Examples 22-25 are given in Table 2. Also in Table 2 are the Onset
Temperature and Time and the Rapid Hydrate Formation Temperature
and Time for distilled water in the absence of a gas hydrate
inhibitor polymer and the Onset Temperature and Time and the Rapid
Hydrate Formation Temperature and Time for a 50 mL solution of
Luvicap 55W, which is a commercial fully synthetic gas hydrate
inhibitor available from BASF.
TABLE-US-00024 TABLE 2 Evaluation of polymers. Rapid Rapid hydrate
hydrate forma- forma- Onset Onset tion tion C P.sub.start Time Temp
time temp Experiment Polymer [ppm] [bar] [min] [.degree. C.] [min]
[.degree. C.] Evaluation Synthesis 5000 77.72 315 15.7 373 14.8
Example 1 Example 22 Evaluation Synthesis 5000 77.32 325 15.5 478
12.9 Example 2 Example 23 Evaluation Synthesis 5000 77.84 499 12.5
519 12.2 Example 3 Example 24 Evaluation Synthesis 5000 77.6 486
12.7 550 11.7 Example 4 Example 25 Comparative No -- 77.27 184 17.9
303 16 Evaluation polymer Example 1 Comparative Luvicap 5000 77.33
422 13.9 751 8.3 Evaluation 55W Example 2
[0169] As can be seen in Table 2, the inventive polymers lowered
both the Onset Temperature and Rapid Hydrate Formation Temperature
compared to when no polymer was added and increased the Onset Time
and Rapid Hydrate Formation Time compared to when no polymer was
added. In addition, the inventive polymers compared favorably to
the commercial kinetic gas hydrate inhibitor polymer with respect
to the Onset Time and Rapid Hydrate Formation Time.
[0170] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention.
[0171] While particular embodiments of the present invention have
been illustrated and described herein, the invention is not
intended to be limited to the details shown. Rather, various
modifications may be made in the details within the range and scope
of equivalents of the claims and without departing from the spirit
and scope of the invention.
* * * * *