U.S. patent application number 10/864635 was filed with the patent office on 2004-12-16 for method for producing ditrimethylolpropane.
Invention is credited to Iwamoto, Atsushi, Kuzuhara, Ikutaro.
Application Number | 20040254405 10/864635 |
Document ID | / |
Family ID | 33410892 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040254405 |
Kind Code |
A1 |
Kuzuhara, Ikutaro ; et
al. |
December 16, 2004 |
Method for producing ditrimethylolpropane
Abstract
In the method of producing ditrimethylolpropane of the present
invention, the distillation still residue obtained in the
production of trimethylolpropane is subjected to crystallizing
treatment while strictly regulating the amount of organic solvent
to be used, the crystallization temperature and the crystallization
time within the specific ranges. With the method of the present
invention, a highly pure di-TMP is obtained only by a single
operation of the crystallization.
Inventors: |
Kuzuhara, Ikutaro; (Okayama,
JP) ; Iwamoto, Atsushi; (Okayama, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET
SUITE 1800
ARLINGTON
VA
22209-9889
US
|
Family ID: |
33410892 |
Appl. No.: |
10/864635 |
Filed: |
June 10, 2004 |
Current U.S.
Class: |
568/680 |
Current CPC
Class: |
C07C 41/40 20130101;
C07C 41/01 20130101; C07C 41/01 20130101; C07C 43/132 20130101;
C07C 41/40 20130101; C07C 43/132 20130101 |
Class at
Publication: |
568/680 |
International
Class: |
C07C 041/01 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2003 |
JP |
2003-169573 |
Claims
What is claimed is:
1. A method for producing ditrimethylolpropane represented by the
following formula 1: 4the method comprising: a step of reacting
n-butyl aldehyde and formaldehyde in the presence of a basic
catalyst to obtain a reaction product solution; a step of
extracting the reaction production solution with an organic
extractant to obtain an extract; a step of distilling the extract
to separate trimethylolpropane as a distillate and obtain a
distillation still residue; and a step of adding an organic solvent
to the distillation still residue in an amount of 0.6 to 10 times a
weight of the distillation still residue, and treating the
distillation still residue at a crystallization temperature Y
.degree. C. satisfying the following formula 3:
(30.times.ln(X)-92).ltoreq.Y.ltoreq.55 (3) wherein X is a percent
by weight concentration of ditrimethylolpropane in the distillation
still residue before adding the organic solvent, for 0.1 to 20 h,
thereby crystallizing ditrimethylolpropane.
2. The method according to claim 1, wherein the organic solvent is
at least one compound selected from the group consisting of
aliphatic ketones and aliphatic esters.
3. The method according to claim 2, wherein the organic solvent is
at least one compound selected from the group consisting of
acetone, methyl ethyl ketone and ethyl acetate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a novel method for
producing ditrimethylolpropane (hereinafter referred to as
"di-TMP").
[0003] 2. Description of the Prior Art
[0004] Highly pure di-TMP has been used as the raw materials for
the production of polyacrylate, polyether polyol, polyurethane,
alkyd resin, synthetic lubricating oil, etc. di-TMP is by-produced
and recovered in the industrial production of trimethylolpropane
(hereinafter referred to as "TMP") by aldol condensation and
crossed Cannizzaro reaction of n-butyl aldehyde (hereinafter
referred to as "NBD") and formaldehyde (for example, U.S. Pat. No.
3,097,245). In the proposed method, a TMP extract (crude TMP)
containing substantially no sodium formate is obtained by
extracting the reaction product solution of the reaction of NBD and
formaldehyde with a solvent, after condensing or without condensing
the reaction product solution. The purification of the crude TMP by
high vacuum distillation leaves a still residue containing 1 to 20%
of TMP and 20 to 50% di-TMP. To recover di-TMP from the still
residue, there have been proposed crystallization from ethyl
acetate (for example, Japanese Patent Application Laid-Open No.
47-30611), crystallization from water in the presence of sodium
formate (for example, Japanese Patent Application Laid-Open No.
49-133311), crystallization from 1,4-dioxane (for example, Japanese
Patent Application Laid-Open No. 2002-47231), etc.
[0005] However, only by the crystallization from the organic
solvent such as ethyl acetate, a highly pure di-TMP is not obtained
from the distillation still residue in the production of TMP. When
the distillation still residue is colored, the contamination of
di-TMP with colored substances is not prevented in the
crystallization from water. Therefore, to obtain a highly pure
di-TMP, the crystallizing operation should be repeated in these
methods.
[0006] It is reported that the crystallization from 1,4-dioxane
enables the recovery of a highly pure di-TMP only in one
crystallizing operation. However, 1,4-dioxane is toxic and easily
converted into explosive peroxide by the reaction with oxygen in
air. Therefore, it is desirable to avoid the use of 1,4-dioxane as
much as possible in the industrial process, because there is a
danger of explosion during the recovery of 1,4-dioxane for reuse by
distilling the filtrate after the crystallization.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide an
efficient and safe method for separating and recovering a highly
pure di-TMP free from the contamination with colored substances
from the distillation still residue in the production of TMP.
[0008] A highly pure di-TMP is not obtained only by a single
operation of crystallization from a general-purpose organic solvent
including ketones such as acetone and methyl ethyl ketone, and
esters such as ethyl acetate and butyl acetate. This is because of
the difficulty to separate a linear formal formed from two moles of
TMP and formaldehyde (hereinafter referred to as "bis-TMP") each
present in the distillation still residue of the crude TMP. As a
result of extensive research in view of solving the above problem,
the inventors have found that, by strictly regulating the amount of
the solvent to be added to the distillation still reside, the
crystallization temperature and the crystallization time within
specific ranges, bis-TMP is separated with great efficiency and a
colorless, highly pure di-TMP is easily and safely obtained only by
a single operation of crystallization. The present invention has
been accomplished on the basis of this finding.
[0009] Thus, the present invention provides a method for producing
ditrimethylolpropane represented by the following formula 1: 1
[0010] the method comprising:
[0011] a step of reacting n-butyl aldehyde and formaldehyde in the
presence of a basic catalyst to obtain a reaction product
solution;
[0012] a step of extracting the reaction production solution with
an organic extractant to obtain an extract;
[0013] a step of distilling the extract to separate
trimethylolpropane as a distillate and obtain a distillation still
residue; and
[0014] a step of adding an organic solvent to the distillation
still residue in an amount of 0.6 to 10 times a weight of the
distillation still residue, and treating the solvent-added
distillation still residue at a crystallization temperature Y
.degree. C. satisfying the following formula 3:
(30.times.ln(X)-92).ltoreq.Y.ltoreq.55 (3)
[0015] wherein X is a percent by weight concentration of
ditrimethylolpropane in the distillation still residue before
adding the organic solvent,
[0016] for 0.1 to 20 h, thereby crystallizing
ditrimethylolpropane.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The aimed compound of the present invention,
ditrimethylolpropane (di-TMP) is represented by the following
formula 1: 2
[0018] and bistrimethylolpropane (bis-TMP) is represented by the
following formula 2: 3
[0019] The distillation still residue to be treated in the present
invention is obtained in the following manner.
[0020] By reacting NBD and formaldehyde in the presence of a basic
catalyst in a manner described, for example, in Japanese Patent
Application Laid-Open No. 11-49708, a reaction production solution
is obtained, which is then extracted with an organic extractant
after condensing or without condensing the reaction product
solution to obtain a TMP extract containing substantially no sodium
formate. Examples of the extractants include aliphatic esters such
as ethyl acetate and butyl acetate; aliphatic ketones such as
methyl ethyl ketone, methyl isobutyl ketone and diisopropyl ketone;
alcohols such as isobutyl alcohol, amyl alcohol, hexyl alcohol and
cyclohexyl alcohol; and aldehydes such as isobutyl aldehyde and
n-butyl aldehyde. These extractants may be used alone or in
combination of two or more. The amount of the extractant to be used
and the extraction conditions are not specifically limited, and the
extracting operation is generally performed at 5 to 55.degree. C.
using the extractant in an amount of 0.5 to 5 times the weight of
the reaction product solution.
[0021] The TMP extract is distilled to remove the organic extract
to obtain a crude TMP, which is further distilled under high vacuum
(0.1 to 5 KPa), thereby separated into TMP and the distillation
still residue. The concentration of di-TMP in the distillation
still residue is preferably about 20 to about 90% by weight. In the
present invention, the distillation still residue thus obtained is
directly added with an organic solvent and subjected to
crystallization under specific conditions to recover di-TMP.
[0022] Examples of the organic solvents for crystallization include
aliphatic ketones, aliphatic esters and tetrahydrofuran, with the
aliphatic ketones and aliphatic esters being preferred, and ethyl
acetate, methyl ethyl ketone and acetone being more preferred.
These organic solvents available as industrial products can be used
as-received without purification.
[0023] The amount of the organic solvent to be used is 0.6 to 10
times, preferably 0.8 to 5 times, more preferably 1 to 3 times the
weight of the distillation still residue. If less than 0.6 times,
TMP and bis-TMP are crystallized together with di-TMP and the
contamination with colored substances is not avoided to reduce the
purity of di-TMP crystals. If exceeding 10 times, the yield of
di-TMP crystals is reduced or di-TMP is not crystallized. In
addition, the load for recovering the organic solvent becomes
excessively large to make the process industrially
disadvantageous.
[0024] The crystallization temperature is Y .degree. C. satisfying
the following formula 3:
(30.times.ln(X)-92).ltoreq.Y<55 (3)
[0025] wherein X is a percent by weight concentration of
ditrimethylolpropane in the distillation still residue before
adding the organic solvent. If higher than the above range, the
yield of di-TMP crystals is reduced or di-TMP is not crystallized.
If lower than the above range, bis-TMP is crystallized in a large
amount in addition to di-TMP to extremely reduce the purity of
di-TMP crystals.
[0026] The crystallization time is 0.1 to 20 h, preferably 0.5 to
10 h, and more preferably 1 to 4.5 h. If shorter than 0.1 h, the
yield of di-TMP crystals is reduced or di-TMP is not crystallized.
If longer than 20 h, bis-TMP is crystallized together with di-TMP
to reduce the purity of di-TMP crystals. In addition, the apparatus
efficiency is lowered to make the process industrially
disadvantageous.
[0027] After added with the organic solvent, the distillation still
residue is stirred until a transparent solution is obtained
optionally under heating, for example, under heating to 56 to
60.degree. C. Thereafter the distillation still residue is cooled
to the crystallization temperature while continuing the stirring to
allow the crystallization to take place. After the crystallization
time specified above is passed, di-TMP crystals are separated from
the resultant slurry by filtration, centrifugation, etc., washed
with the organic solvent and dried to obtain highly pure,
preferably 94 to 100% purity (weight basis) of di-TMP crystals.
[0028] The organic solvent recovered by distilling the filtrate and
washings obtained in the crystallization step may be reused as the
solvent for recrystallization together with the organic solvent
recovered during the drying operation of di-TMP crystals.
[0029] In the present invention, by subjecting the distillation
still residue obtained after the distillation of TMP to the
crystallization treatment under the amount of the organic solvent,
crystallization temperature and crystallization time which are
regulated within the specific ranges, di-TMP which is free from
bis-TMP and colored substances even when the Gardner color scale of
the distillation still residue is 10 or more is obtained from the
distillation still residue with great efficiency only by a single
operation of the crystallization.
[0030] The present invention will be explained in more detail by
reference to the following examples which should not be construed
to limit the scope of the present invention.
[0031] In the following examples and comparative examples, the
degree of coloring was measured according to JIS K 0071-2 (Gardner
color scale) and JIS K 1510 (phthalic acid resin color). The
percentage and ppm are based on weight.
PRODUCTION EXAMPLE
[0032] In accordance with the procedure of Example 1 described in
Japanese Patent Application Laid-Open No. 11-49708, NBD and
formaldehyde were reacted to produce TMP. After completing the
reaction, TMP was extracted from the reaction production solution
with NBD as the extractant. After recovering or removing
low-boiling starting materials and by-products, the extract (crude
TMP) was distilled by a film evaporator to obtain a distillation
still residue. The composition of the distillation still residue is
shown below.
1 TMP 7.7% di-TMP 44.7% bis-TMP 27.4% Organic by-products 19.9%
Salts 3000 ppm Gardner color scale 10
EXAMPLE 1
[0033] In a 3000-mL round bottom flask equipped with a mechanical
stirring device, 1300 g of the distillation still residue obtained
above and 1300 g of acetone were stirred under heating until the
mixture changed to a transparent solution. Then, the solution was
cooled to 30.degree. C. under stirring and subjected to the
crystallizing treatment for 2 h while keeping the temperature at
30.degree. C. Crystals separated from the resultant slurry by
centrifugation were washed with 250 g of acetone and dried to
obtain 256 g of crystals. The obtained crystals showed a di-TMP
purity of 96%, a melting point of 109.degree. C. and a phthalic
acid resin color of 1.
EXAMPLE 2
[0034] In a 1000-mL round bottom flask equipped with a mechanical
stirring device, 250 g of the distillation still residue obtained
above and 500 g of ethyl acetate were stirred under heating until
the mixture changed to a transparent solution. Then, the solution
was cooled to 40.degree. C. under stirring and subjected to the
crystallizing treatment for 1.5 h while keeping the temperature at
40.degree. C. Crystals separated from the resultant slurry by
suction filtration were washed with 40 g of ethyl acetate and dried
to obtain 40 g of crystals. The obtained crystals showed a di-TMP
purity of 96%, a melting point of 109.degree. C. and a phthalic
acid resin color of 1.
COMPARATIVE EXAMPLE 1
[0035] In the same manner as in Example 1 except for changing the
amount of acetone used to 650 g, 314 g of crystals were obtained.
The obtained crystals showed a di-TMP purity of 86%, a melting
point of 96.degree. C. and a phthalic acid resin color of 3.
COMPARATIVE EXAMPLE 2
[0036] In the same manner as in Example 1 except for changing the
crystallization temperature to -5.degree. C., 689 g of crystals
were obtained. The obtained crystals showed a di-TMP purity of 56%,
a melting point of 83.degree. C. and a phthalic acid resin color of
5.
COMPARATIVE EXAMPLE 3
[0037] In the same manner as in Example 1 except for changing the
crystallization time to 25 h, 291 g of crystals were obtained. The
obtained crystals showed a di-TMP purity of 90%, a melting point of
104.degree. C. and a phthalic acid resin color of 2.
[0038] As described above, in the method of the present invention,
the distillation still residue in the production of
trimethylolpropane is subjected to crystallizing treatment while
strictly regulating the amount of organic solvent to be used, the
crystallization temperature and the crystallization time within the
specific ranges. With such a method, a highly pure di-TMP is
obtained only by a single operation of the crystallization. Thus,
the present invention is of great industrial advantage.
* * * * *