Preparation process for plasticizer-tributyl citrate

Abstract

The invention belongs to the field of fine chemical synthesis, and particularly relates to a synthesis process for tributyl citrate. The synthesis process comprises the steps as follows: (1) mixing citric acid monohydrate with n-butyl alcohol, then adding p-toluenesulfonic acid and active carbon, and adding nitrogen for performing esterification reaction to obtain an esterified substance; (2) dealcoholizing the esterified substance for the first time until the flash point is not less than 162 DEG C; (3) dissolving and recovering the p-toluenesulfonic acid in the esterified substance after dealcoholization by water, and adding the separated water phase into the preparation step (1) of next batch for recycling; (4) adding an alkali solution into an oil phase for neutralizing, removing the water phase, and washing the oil phase to be neutral by water; (5) adding the active carbon into the esterified substance after washing, and dealcoholizing again until the flash point is not less than 180 DEG C so as to obtain raw ester; and (6) filtering the raw ester to obtain the tributyl citrate as the industrial product. According to the synthesis process, the esterification reaction conversion rate reaches up to above 99.0%, the yield of the tributyl citrate can reach above 98%, and the unit consumption and the cost are reduced; and the catalyst, namely the p-toluenesulfonic acid has a good catalytic effect, the recovery rate reaches above 75% after the esterification reaction is ended, the p-toluenesulfonic acid can be repeatedly used as the catalyst, the pollution discharge is reduced, and the COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand) in wastewater are reduced.

Description

technical field [0001] The invention belongs to the field of fine chemical synthesis, and in particular relates to a synthesis process of tributyl citrate. Background technique [0002] Tributyl citrate is a green and environment-friendly plasticizer, widely used in food and medical device packaging, cosmetics, daily necessities and other industries. It has gradually replaced traditionally used phthalates and has become the main plasticizer in the plastics industry. The traditional production method of tributyl citrate uses concentrated sulfuric acid as a catalyst, which has the disadvantages of oxidation and other side reactions, difficult refining, serious equipment corrosion, and environmental pollution. In recent years, some factories have used p-toluenesulfonic acid as a catalyst, which has a good catalytic effect, but the amount of catalyst used is relatively large, and the price is relatively expensive. There is no recovery and recycling method found, and the producti...

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Problems solved by technology

The traditional production method of tributyl citrate uses concentrated sulfuric acid as a catalyst, which has side reactions such as oxidation, difficult refining, serious equipment corrosion, and environmental pollution.

In recent years, some factories

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