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Preparation method of 3-methyl-1, 5-pentanediol

A technology of pentanediol and methylpentane, which is applied in the field of preparing 3-methyl-1,5-pentanediol, can solve the problems of increased separation energy consumption, reduced selectivity and high cost, and can improve the reaction rate and reaction rate. Equilibrium constant, reaction to reduce double bond hydration, effect to reduce ratio of isomers

Active Publication Date: 2022-01-04
WANHUA CHEM GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In the process of synthesizing MPD in traditional technology, there are many side reactions and low product yield, such as the direct hydroformylation process of 3-methyl-3-ene-1-butanol disclosed in US4663468, the reaction selectivity is only about 50%, More by-products are produced, and the reaction by-products include isovaleraldehyde, two (4-methyl-tetrahydropyran-2-methyl) ether (main by-product), 3-methyl-5-[(4-methyl -2H-pyran-2-yl)oxy]-pentanal, 4-methyl-2-[(3-methyl-3-butenyl)oxy]-2H-pyran, etc.
[0004] CN101432255 provides a method for preparing 3-methyl-1,5-pentanediol by hydrogenating 2-hydroxyl-4-methyltetrahydropyran in the presence of a hydrogenation catalyst. The 2-hydroxyl- 4-Methyltetrahydropyran has few sources of raw materials, high cost and poor production economy
[0005] US6072089 (A) describes the method of using dibutene derivatives and formaldehyde as raw materials, condensation reaction occurs under the action of a basic catalyst, and then hydrogenated to obtain 1,5-pentanediol derivatives. The reaction time is long, reaching 1 ~10h, low production capacity, large reactor volume, because the basic catalyst will cause the disproportionation reaction of formaldehyde, long reaction time will also lead to increased disproportionation of formaldehyde, lower selectivity, the subsequent basic catalyst needs to be removed by washing, resulting in a large amount of waste water, The cost of treating the three wastes is high, and at the same time, a solvent needs to be added to make the reaction system reach a homogeneous state, which increases the energy consumption of subsequent separation
Most of its raw materials such as 2-methyl-2-pentenal, diethyldixenal, and diethyldicrolein need to be obtained through complex reactions, which are costly, and aldehydes are in alkaline environment Unstable, not suitable for industrial scale-up
[0006] It can be seen that there are many shortcomings in the current synthesis of 3-methyl-1,5-pentanediol. How to improve atom economy, improve product yield, and reduce the occurrence of side reactions is a technology that needs to be broken through in this field. difficulty

Method used

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  • Preparation method of 3-methyl-1, 5-pentanediol

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042]1) First, add 180g (3.2mol) of isobutylene into the autoclave, start stirring and raise the temperature to 275°C, and the pressure to 9MPa, then add 1.2g of catalyst propane sulfonate pyridinium salt, 0.3g of auxiliary ferrous phosphate, and then add 900g of 50wt % (14.9mol) formaldehyde aqueous solution, the pH of the system is 6.8 after adding the material, and react at 275°C for 20 minutes. After the reaction is completed, a cooling liquid is passed to cool down, and the unreacted isobutene is recovered by flash evaporation, and then rectified and separated to obtain the condensation product 3 -Methylenepentane-1,5-diol and 3-methylpent-2-ene-1,5-pentanediol, formaldehyde conversion 95.6%, 3-methylenepentane-1,5-diol Alcohol selectivity was 93.2%, and 3-methylpent-2-ene-1,5-pentanediol selectivity was 6.1%.

[0043] NMR spectrum of 3-methylenepentane-1,5-diol:

[0044] 1 H-NMR (CDCl 3 )δ: 2.15(4H), 3.57(4H), 3.65(2H), 4.92(1H), 5.11(1H)

[0045] NMR spectrum of 3-...

Embodiment 2

[0051] 1) First, add 250g (4.5mol) of isobutene into the autoclave, start stirring and raise the temperature to 185°C, and the pressure to 6MPa, then add 24g of catalyst pyridine mesylate, 1.2g of sodium dihydrogen phosphate, and then add 542.95g 37% (6.7mol) formaldehyde aqueous solution, the pH of the system is 4 after adding the material, and then react at 185 ° C for 10 minutes. After the reaction is completed, the cooling liquid is passed to cool down, and the unreacted isobutene is recovered by flash evaporation, and then separated by rectification to obtain the condensation product 3-Methylenepentane-1,5-diol and 3-methylpent-2-ene-1,5-pentanediol, formaldehyde conversion 95.2%, 3-Methylenepentane-1,5- The selectivity to diol was 95.2%, and the selectivity to 3-methylpent-2-ene-1,5-pentanediol was 4.6%.

[0052] 2) Take 100g of the 3-methylenepentane-1,5-diol and 3-methylpent-2-ene-1,5-pentanediol mixture obtained in step 1) and add 1.2g RC-311 as Hydrogenation catalys...

Embodiment 3

[0054] 1) First, add 300g (5.3mol) of isobutene into the autoclave, start stirring and raise the temperature to 200°C, and the pressure to 10MPa, then add 20g of the catalyst pyridinium p-toluenesulfonate, 13g of the auxiliary agent disodium dihydrogen pyrophosphate, and then add 1004.4g of 40% (13.4mol) formaldehyde aqueous solution, the pH of the system after adding the material is 3, react at 200°C for 15min, after the reaction is completed, pass in a cooling liquid to cool down, recover unreacted isobutene by flash evaporation, and then carry out rectification and separation to obtain condensation Products 3-methylenepentane-1,5-diol and 3-methylpent-2-ene-1,5-pentanediol, formaldehyde conversion rate 96.40%, 3-methylenepentane-1,5 -diol selectivity 96.40%, 3-methylpent-2-ene-1,5-pentanediol selectivity 3.4%.

[0055] 2) Take 100g of the 3-methylenepentane-1,5-diol and 3-methylpent-2-ene-1,5-pentanediol mixture obtained in step 1) and add 9.5g of 1,1- Bis(di-tert-butylpho...

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Abstract

The invention provides a preparation method of 3-methyl-1, 5-pentanediol, which comprises the following steps of: (1) carrying out a condensation reaction on isobutene and formaldehyde as raw materials under the action of an acid catalyst and an auxiliary agent to generate 3-methylene pentane-1, 5-diol and 3-methyl pentyl-2-ene-1, 5-pentanediol; and (2) carrying out a hydrogenation reaction by taking the 3-methylene pentane-1, 5-diol and the 3-methyl pentyl-2-ene-1, 5-pentanediol as raw materials to obtain 3-methyl-1, 5-pentanediol. A sulfoacid pyridinium salt is used as a catalyst and phosphate is used as an auxiliary agent in the condensation reaction of isobutene and formaldehyde, so that the product yield can be obviously improved. The method has the advantages of short process steps, high yield and low cost, and is suitable for industrial amplification.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, and specifically relates to a method for preparing 3-methyl-1,5-pentanediol by using isobutylene and formaldehyde as raw materials, first performing condensation reaction, and then hydrogenating. Background technique [0002] 3-Methyl-1,5-pentanediol (MPD) is a polyol widely used in polyester resins, alkyd resins for coatings, etc., and its synthesized ester products are used in coatings and plastic plasticizers Wait. [0003] In the process of synthesizing MPD in traditional technology, there are many side reactions and low product yield, such as the direct hydroformylation process of 3-methyl-3-ene-1-butanol disclosed in US4663468, the reaction selectivity is only about 50%, More by-products are produced, and the reaction by-products include isovaleraldehyde, two (4-methyl-tetrahydropyran-2-methyl) ether (main by-product), 3-methyl-5-[(4-methyl -2H-pyran-2-yl)oxy]-pentanal, 4-methyl-2-[(...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/17C07C31/20C07C29/38C07C33/035
CPCC07C29/38C07C29/172C07C33/035C07C31/20
Inventor 庞计昌朱小瑞刘英俊张红涛沈元伟安丽艳张永振
Owner WANHUA CHEM GRP CO LTD
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