Second-stage reaction process for preparing propenoic acid or ester from lactic acid or ester

A two-stage reaction and acrylic acid technology, which is applied in the preparation of carboxylic acid salts, chemical instruments and methods, and the preparation of organic compounds, etc., can solve the problem of low selectivity of acrylic acid and esters, and achieve the effect of stabilizing the reaction system and improving selectivity

Inactive Publication Date: 2008-11-19
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Previous studies have made some progress, but the selectivity of acrylic acid and esters is relatively low (hereinafter referred to as the total selectivity of acrylic acid and acrylates is selectivity)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0019] The experiment uses a fixed-bed reactor with 13X molecular sieve as the reaction catalyst. The raw material is 60% lactic acid and methyl ester aqueous solution, 5‰ of p-hydroxyanisole is added, and 2g of 10-100 mesh 13X molecular sieve is weighed. The reaction temperature is 300°C, the vaporization temperature is 235°C, the raw material injection speed is 1.5ml / h, the nitrogen flow rate is 5ml / min, and the product selectivity is 45%.

[0020] The reaction temperatures in Example 1 were respectively set to 275° C. and 325° C., and other experimental conditions remained unchanged, and product selectivities of 21% and 38% were obtained respectively.

[0021] When the raw materials in Example 1 were replaced with 40% methyl lactate, 80% methyl lactate, 60% ethyl lactate, 80% ethyl lactate, 40% lactic acid and 60% lactic acid aqueous solution, other experimental conditions remained unchanged , the selectivities of the products obtained respectively are as follows: 27%, 33%,...

example 2

[0023] The experiment adopts a fixed-bed reactor, and KY molecular sieve is used as the catalyst for the reaction. The catalyst preparation process is shown in the preparation method of catalyst B in (1) above. The raw material is 60% lactic acid and methyl ester aqueous solution, and 5‰ of p-hydroxybenzene Methyl ether, the catalyst loading amount is 2g, the reaction temperature is set to 325°C, the vaporization temperature is 235°C, the raw material injection speed is 2ml / h, the nitrogen flow rate is 10ml / min, and the product selectivity is 43%.

[0024] The reaction temperatures in Example 2 were respectively set to 300° C. and 350° C., and other experimental conditions were kept constant, and product selectivities of 17% and 39% were obtained respectively.

[0025] When the raw materials in Example 2 are replaced with 40% methyl lactate, 60% ethyl lactate and 40% lactic acid aqueous solution respectively, other experimental conditions are constant, and the selectivity of th...

example 3

[0027] The experiment adopts a section of fixed-bed reactor, uses praseodymium phosphate as the catalyst of reaction, the catalyst preparation process sees the preparation method of catalyst C in the above (1), raw material is 60% lactic acid and methyl ester aqueous solution, adds 5% p-hydroxybenzene Methyl ether, the loading amount of the catalyst is 2g, the reaction temperature is set to 325°C, the vaporization temperature is 235°C, the raw material injection speed is 1.5ml / h, the nitrogen flow rate is 10ml / min, and the product selectivity is 40%.

[0028] The reaction temperatures in Example 3 were respectively set to 300° C. and 350° C., and other experimental conditions were kept constant, and product selectivities of 19% and 35% were obtained respectively.

[0029] When the raw materials in Example 3 were replaced with 80% methyl lactate, 60% ethyl lactate and 40% lactic acid aqueous solution respectively, other experimental conditions were unchanged, and the selectivity...

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Abstract

The invention relates to a two-section reaction method for preparing acrylic acid or propylene ester by lactic acid or lactic ester, belonging to the biological matrix chemical product field. A two-stage vertical type fixed bed reactor is adopted; a front part of an upper-section reactor is connected with a material carburetor; a lower-section reactor is connected with a gas-liquid separator; catalyzers A,B,C and D are adopted, wherein, the catalyzer A is an X-type molecular sieve; a NaY-type molecular sieve is roasted, subject to ion exchange by a potassium nitrate solution to prepare the catalyzer B; a nitrate solution and sodium phosphate are used to prepare phosphate as the catalyzer C; and a mixture of CaSO4 and CuSO4 and phosphate are mixed to prepare the catalyzer D; the catalyzer A or B is positioned in the upper-section reactor; the catalyzer C or D is positioned in the lower-section reactor; air in the reactors is exhausted by nitrogen; the nitrogen flow speed is between 5 and 100 ml / min; the temperature of the carburetor is 235 DEG C; the upper-section reaction temperature is between 275 and 350 DEG C; the lower-section reaction temperature is between 350 and 450 DEG C; and a condensed liquid of the gas-liquid separator is kept at a temperature of 2 DEG C; after the temperature is stabilized, raw material is pumped to the carburetor; the raw material is an aqueous solution of the ethyl lactate and the methyl lactate or a lactic acid aqueous solution added with a polymerization inhibitor of 0.5 percent of the raw material mass; and the sampling speed of the raw material is between 0.5 and 2 ml / h. The method develops the advantages of different catalyzers and improves the selectivity of a target product.

Description

technical field [0001] The invention belongs to the field of bio-based chemicals, and relates to the process of preparing acrylic acid or esters by catalytic dehydration of lactic acid or esters in a fixed-bed reactor. The experiment adopts the production method of a two-stage fixed-bed reactor. Background technique [0002] Acrylic acid is one of the important basic chemical raw materials. It is widely used in coatings, chemical fibers, textiles, light industry and other industries, as well as in oil exploration, oil additives and other fields. It is widely used and has a large market demand. The market demand has been showing an upward trend in recent years. Especially in Asia. [0003] At present, acrylic acid is basically synthesized from petrochemical products, most of which are produced by propylene oxidation. However, fossil resources are non-renewable. With the further aggravation of the global energy crisis, how to use renewable biological resources is becoming mor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/065C07C51/377B01J8/04B01J38/12
CPCY02P20/584
Inventor 谭天伟韩超杨超黄辉
Owner BEIJING UNIV OF CHEM TECH
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