JPS58167532A - Separation method of butanediol - Google Patents

Abstract

PURPOSE:To obtain the titled compound efficiently in high purity, by hydroformylating allyl alcohol, hydrogenating the resultant hydroformylation product, and heating the resultant crude butanediol mixture in the presence of a ruthenium catalyst, water and hydrogen, and distilling and separating the titled compound. CONSTITUTION:Allyl alcohol is hydroformylated, and the resultant product is then hydrogenated to give a crude butanediol mixture, which is then heat-treated at preferably 80-150 deg.C and 30-50kg/cm<2> in the presence of a ruthenium catalyst, water and hydrogen. The heat-treated product is then distilled and separated into 2-methyl-1,3-propanediol and 1,4-butanediol to give high-purity butanediol usable for polymerization. According to the method, impurities to inhibit the distillatory separability of the butanediol are decomposed reductively by the above-mentioned heat treatment, and the above-mentioned separability is remarkably improved. Thus, the purity of the aimed compound is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating butanediol by which 2-methyl-1,5-propanediol (hereinafter abbreviated as MPG) of high purity can be obtained.

By hydroformylation of allyl alcohol, 3- or 2-
A mixture of propatool (hydroxybutyraldehydes) formylated at the - position is obtained, and this is catalytically hydrogenated to produce butanediols, that is, 1,4-butanediol (hereinafter abbreviated as 1.4-BG). It is known that mixtures of MPG and MPG can be obtained. For example, the special public service in 1973-
No. 19563 discloses that allyl alcohol and synthesis gas (H, + Co) are reacted in the presence of a rhodium-containing catalyst in an organic solvent such as benzene, and the reaction product aqueous solution separated from the rhodium catalyst is separated from the rhodium catalyst through a water extraction trap. Catalytic hydrogenation is performed using a known hydrogenation catalyst such as Raney nickel to produce 1.4-B.
It is disclosed that a liquid containing G and MPG can be obtained. After water and low-boiling byproducts are distilled off from such a crude butanediol mixture, MPG (
BP 215°C) and 1.4-BG (BP 250
℃) is considered to be a conventional separation method.

However, with this method, MPG with good purity can be converted into 1.4-B
It has been found that there are some difficulties in separating G and G in an efficient manner. That is, in the crude butanediol mixture obtained by hydroformylation of allyl alcohol and catalytic hydrogenation, there are impurities specific to this production method, and these are
It was found that this had an adverse effect on the separation of 1.4-BG and 1.4-BG. To be more specific, in hydrogenated foods, the aldehydes used as raw materials and the nine alcohols produced react with each other 1-b.
Various by-products are produced, and their quantitative relationships vary significantly depending on the conditions. The presence of these by-products is intended for purposes 1 and 4.
- This is dangerous because it seriously impairs the quality of G and MPG, and makes it extremely difficult to separate the target diols by distillation, and in some cases makes it impossible to perform the separation itself by ordinary distillation.

The present inventor conducted research with the aim of obtaining high-purity butanediols that can be used for polymerization, and focused on the above facts for the first time, and as a result of his studies, he determined that the impurity process that has a negative effect on the separation of MPG and L4-B Ck was found. We have found a specific technical means to efficiently obtain MPG and 1.4-BG with good purity by preventing these effects.

That is, as a result of the study, it was found that the 3m impurity present in crude butanediol should be noted as a substance that has an adverse effect on the presence of MPG and 1.4-BG. Four of them are 2-mef-1, which are thought to be produced by isomerization of allyl alcohol and hydrogenation of an aldol condensate of nine-propionaldehyde. s-hentanediol (hereinafter referred to as M
(abbreviated as PIG) and has almost the same boiling point as MFG.

The second is a hydrophorzol compound of allyl alcohol 4
2-(5-hydroxy-2-methylp4poxy)-tetrahydrofuran (hereinafter abbreviated as HMPTHI), which is an ether of 2-hydroxytetrahydrofuran and MPG in which -hydroxybutyraldehyde is intramolecularly cyclized,
The presence of this substance makes the separation of FiMPG and 1.4-BG very difficult and often almost impossible. The cause Fi) IMPTHF is 1.4- B G
This is thought to be because it forms an azeotropic mixture with MPG, which exhibits almost the same vapor pressure as MPG. However, the physical properties of the azeotrope with The fifth impurity, 2-(4-hydroxybutoxy)-tetrahydrofuran (hereinafter abbreviated as HBTHIF), is an ether of 2-hydroxy-tetrahydrofuran and 1,4-BG; A boiling mixture is formed whose boiling point is between that of MPG-1,4-BG, making it difficult to separate the two.

The present inventor discovered that the separability of a crude butanediol mixture obtained by two processes of hydroformylation and catalytic hydrogenation using allyl alcohol as a starting material was inhibited by the three types of impurities mentioned above. Then, when the crude butanediol mixture is heat-treated in the presence of a ruthenium catalyst, water and hydrogen, the impurity 311 is reductively decomposed and MP
The present invention was completed after confirming that the distillation separation between G and 1.4-B G was dramatically improved.

That is, in the present invention, a crude butanediol mixture obtained by catalytic hydrogenation of a hydroformylation product of allyl alcohol is heat-treated in the presence of a ruthenium catalyst, water and hydrogen, and then converted into 2-methyl-1,3-propanediol. 1.4-
This is a book about a method for separating butanediol, which is characterized by separating butanediol by distillation.The crude butanediol mixture, which is the subject of the present invention, is prepared by reductive hydrogenation using a catalyst such as Raney nickel. Although it is obtained through industrial processing, it can be treated again in the presence of a specific catalyst to obtain the decomposition effect unique to the present invention. The catalyst that is effective in the present invention is limited to ruthenium catalysts, which are commonly thought of as hydrogenation catalysts, namely Ni.

Catalysts based on base metals such as CO and noble metals such as PT and PA showed almost no reductive decomposition effect on impurities.

Although the ruthenium catalyst used in the present invention does not necessarily require this carrier, the treatment can be carried out preferably by using a suitable carrier. The carrier is not particularly limited, but representative examples include activated carbon, silica, and alumina. The amount of ruthenium supported on these carriers is 0.2
A range of 20 to 20 parts by weight is preferred. Even if it exceeds 20% by weight, it does not affect the decomposition effect, but it is not economical.

It is sufficient that the amount of water is equivalent to or more than the impurities to be removed by reductive decomposition.Of course, the presence of a large amount of water significantly increases the papermaking reaction rate. For heat treatment in the presence of hydrogen, pressurization and high temperature are generally preferable in terms of speed, and although not particularly limited, from an economical point of view, 80 to 150°C, 30 to 50ky/11+-G 1
it (D condition is preferable.

According to the present invention, if it is a crude butanediol mixture containing MPG, 1.4-BG, and any of the impurities mentioned above, even if the liquid is in the middle of the purification process, MPG or 1.4-BG that has already been separated may be used. - Even crude BG products can be treated under the above conditions to improve distillation separation! ! Example 1 Allyl alcohol was subjected to a hydroformylation reaction in the presence of a Rh-catalyst, and hydroxybuyraldehydes were extracted with water.This extract was treated with a Raney nickel catalyst. Hydrogenation reaction is carried out in the presence of hydrogen, and the resulting reaction liquid is removed from low boiling point by distillation.

After dehydration, crude butanediol was obtained by distillation using an Oldershaw column. To this aqueous solution to which 190 tons of 20FK pure water was added was added 2 f of commercially available 5-grade ruthenium thiacol (Nihon Enge/'k)'', the mixture was charged into a 500 autoclave and H2 was heated to 5 o (
After stirring until VeIII'·e), the mixture was heated with a TOOC for 5 hours.

K in crude butanediol 4. Go-Exist 91'IBT
HF was reduced to 1 trace by heat treatment in the presence of ruthenium, water, and hydrogen. The composition after heat treatment (excluding water) is M
P a 77, [11 honors, 1. a-B G
22.21, traces of MPIG, Hht, pTgy undetected, ttl, MPG and 1.4-BG tl easily separated by distillation 90 Comparative Example 1 Same crude butanediol mixture as Example 1 1° fKD
I added 1f of IM IH and performed the reduction process! IBT
I'lF did not decrease at all, and the distillation separation of MPG and 1.4-BG was almost improved. .

Equimole of dihydrofuran and 1.4-B G H280
゜The reaction was carried out in the presence of a catalyst, and the reaction solution was purified by distillation.

The composition of the obtained distillate was HBTHF 57.8wt4.
1.4- 190f of pure water was added to 20g of this distillate, which was 4j2 wt%, and heat-treated at 100°C for 1 hour at H2 pressure of 50 (k7cm-G) in an autoclave with 5gb of commercially available ruthenium charcoal catalyst 2F. I went. The decomposition rate of HBT) IF is 100-Teari, Ko (7) Uchi99,215 (1,4-BG, 0
．． 5% was n-butanol, 0.2% was r-butyrolactone, and 11 g was 4-hydroxybutyraldehyde.

Comparative Example 2 A liquid containing TFIT) IF was heat-treated in the same manner as in Example 2, except that a commercially available Raney nickel catalyst 2f was used instead of the ruthenium catalyst. The decomposition rate of HBTHlr is 31.6
Unfortunately, 96 of the particles were converted to 1,4-BG and -4 to n-butanol.

Example 6 The crude butanediol fraction before ruthenium treatment obtained by a process similar to Example 1 was further filtered and distilled and separated in O-Rudas columns.1. Nine. Did you get it? 7PG fraction #'iMPG pure fraction s
o, so s 1.4-R ('+ 4,7816 plus MPIG 4,40%, HMPTFIIF 7,65
%,) I'BTHFO, 8996, etc., to this crude butanediol mixture 209 mainly composed of MPG, 19Of pure water and 2F of a commercially available 51 ruthenium charcoal catalyst were added, and the mixture was heated with hydrogen under stirring in an autoclave. Heat treatment was performed at a pressure of 50 kV'cm'G and 100°C for 2 hours. Liquid composition (excluding water < ) h) JPG
90.88-11.4-BG 743911MP! !
! G trace level, HMPTT (F 1,05Is, HB
TH! The distillation separation of F-undetected MPG 1.4-BG was significantly improved.

Comparative Example 3 Heat treated as in Example 5 and rFf1 except that commercially available Raney nickel catalyst 2f was used in place of the ruthenium catalyst. After treatment MPKGi-j 5,52%, FfMPTHIF
was 7.02 - hardly reductively decomposed.

Reference Example 1 MPG fraction 410f obtained by distilling the crude butanediol fraction before ruthenium treatment obtained by a process similar to Example 1 using an Oldershaw column was packed in a 15φ, 1.0 height nanobag. Charge the flask of the tower, and the top pressure of the tower is 11
Vacuum distillation was performed on 1111 g. At this time, the reflux ratio ti2
8. The can temperature was 130° C., and after collecting 4 fractions of distillate every 20 2, the composition of each fraction and the can was analyzed.

The results are shown in Table 1. MP! l! Impurities such as G and HMPTHF are present in each fraction! Separability between Tagaari MPG and 1.4-BG is extremely poor.

Table 1 Reference Example 2 A liquid 150F containing only trace amounts of MPIG and HMPTHF was charged into a flask of a Naniwa Pack packed column of 15 φ and 1 mm, and vacuum distillation was carried out at a top pressure of 201111 Hg. The reflux ratio at this time was 18. The temperature of the can is about 140C and the distillation rate is about 60. We analyzed each fraction and the can composition when chilled distillation was carried out.9. As shown in Table 2, the results show that although the 4 reflux ratio is lower than that of Reference Example 1, MPG and 1.4-BG
Separability has been significantly improved.

Table 2 Reference Example 3 In order to confirm that the presence of FIBTHF worsens the separation between MPG and 1.4-BG, 11BTHF to 1.4B
The result of measuring the gas-liquid equilibrium of the G system under a vacuum of 50 wmTIg is F! BTHF' Fil, 4-BG and 1! BT
FI? [The specific volatility of HBTHF and 1.4-BG systems is small and 1,4-
It has been found that it is very difficult to separate T(BTPIF) from the BG fraction.

Claims (1)

[Claims] A crude butanediol mixture obtained by catalytic hydrogenation of the hydrophorylation product of 71J alcohol was heat-treated in the presence of a ruthenium catalyst, water and hydrogen, and then 2-methyl-1,5-propanediol and 1, A method for separating butanediol from 4-butanediol by distillation.