Preparation method of diethylene glycol dibenzoate

Abstract

The invention discloses a method for preparing diethylene glycol dibenzoate ester, which relates to a process for preparing diethylene glycol dibenzoate ester (DEDB) which functions as a plasticizer of organic chemical products. First, benzyl acid and diglycol with the weight ratio of 2: 1-1.1 are taken; then, protonic acid is taken as a catalyst, which has a weight 0.01-0.02 time of the overall weight of benzyl acid and diglycol; then, benzyl acid and diglycol are put into a reactor to be stirred and heated up to 90-200 DEG C, and the catalyst is added; then saturated hydrocarbons is added as a water-carrying agent, and the temperature is adjusted to 90-160 DEG C with heat preservation for 6-16h until the reaction is fully conducted; at the temperature, the water-carrying agent is vacuumed and removed to get a crude product of diethylene glycol dibenzoate ester; finally, alkali is added for neutralization to remove the catalyst; then, decolorization and leaching are carried out in sequence to get diethylene glycol dibenzoate ester. The method for preparing diethylene glycol dibenzoate ester has the advantages that as the saturated hydrocarbons water-carrying agent is used, under the catalysis of protonic acid, the reaction temperature is effectively lowered, thus inhibiting production of side products; the conversion rate reaches 98 percent; the yield coefficient is high; the cost of the product is low; and the method has strong industrial production value.

Description

technical field [0001] A preparation method of diethylene glycol dibenzoate relates to a preparation process of diethylene glycol dibenzoate (DEDB) as a plasticizer for organic chemical products. Background technique [0002] Plasticizers are the most widely used additives in the processing and production of PVC and other plastics. They are widely used in many fields such as synthetic rubber, coatings, adhesives, and chemical synthesis. Phthalate esters (DOP), as plastic plasticizers, account for more than 80% of the market share of plasticizers due to their relatively easy availability of raw materials and low prices. However, after DOP was suspected of carcinogenicity by the National Cancer Institute (NCI), other uses were greatly restricted. Compared with DOP, diethylene glycol dibenzoate (DEDB) has the characteristics of good compatibility, good cold resistance, antistatic property, remarkable anti-pollution performance, outstanding thermal stability, low volatility, an...

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Problems solved by technology

B, Wu Qingyin, etc. In "Liaoning Chemical Industry", 1992(2), pp. 38-40; Jiang Wei in "Chemical World", 2001(2), p. 75, using toluene as a solvent to carry water, heteropolyacid As a catalyst to prepare diethylene glycol dibenzoate (DEDB), but the source of the catalyst is small and the price is high, so the product cost is high

C, Wang Ying, disclosed in "Journal of Shenyang Institute of Education", 2005 (7)) that toluene is used as solvent and p-toluenesulfonic acid is used as catalyst. Although the side reactions of the reaction are controlled to a certain extent, the color of the product is dark due to the high temperature

D, Gao Yonghui et al. in "Journal of Foshan Institute of Science and Technology", 2000 (18), pages 43-46, provided a study on the use of xylene as a water-carrying agent and basic alumina as a catalyst to catalyze the synthesis of plasticizer DEDB. This method has a high reaction temperature, troublesome operation, and filtration is used for post-treatment, while DEDB is relatively viscous and has a large loss

E, Ren Weiheng, in "Journal of South Central University for Nationalities", 1995 (14) page 10-13, reported using dimethylbenzene as solvent, stannous chloride as catalyst to prepare diethylene glycol dibenzoate (DEDB), The method has a high reaction temperature, troublesome post-processing and operation

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