Method of synchronously preparing DL-tartaric acid and DL-potassium hydrogen tartrate

Abstract

The invention discloses a method of synchronously preparing DL-tartaric acid and DL-potassium hydrogen tartrate. The method comprises the following steps: 1) sequentially adding deionized water, maleic anhydride and hydrogen peroxide in a reactor, heating and raising temperature to take reaction; 2) adding phosphorus-molybdenum heteropoly acid as a catalyst into the product obtained in the step 1), and slowly raising the temperature; 3) preserving heat at 70-74 DEG C and taking reaction for 18-22 hours; raising the temperature to 105-115 DEC C, taking hydrolysis reaction for 3-4 hours to obtain a solution comprising 2,3-epoxysuccinic acid; reducing the temperature of the solution comprising 2,3-epoxysuccinic acid to 6-8 DEG C, and naturally crystallizing; and then, performing suction filtration, wherein the obtained filtrate is primary mother solution, and the obtained crystal is dried to obtain DL-tartaric acid; and 4) regulating the pH value of the primary mother solution to 3.5-3.8 by a potassium hydroxide solution with the mass concentration of 45-55%; reducing the temperature to room temperature, and naturally crystallizing, and then performing suction filtration, wherein the obtained filtrate is secondary mother solution, and the obtained crystal is dried to obtain DL-potassium hydrogen tartrate.

Description

technical field [0001] The invention relates to a method for preparing DL-tartaric acid, in particular to a method for simultaneously preparing DL-tartaric acid and DL-potassium hydrogen tartrate. Background technique [0002] Tartaric acid, namely, 2,3-dihydroxysuccinic acid, is a carboxylic acid that exists in various plants such as grapes and tamarind, sweet horn, and is also one of the main organic acids in wine. There are two asymmetric carbon atoms in the tartaric acid molecule, so there are three optical isomers, namely, L-tartaric acid or L-tartaric acid, D-tartaric acid or D-tartaric acid, and meso-tartaric acid. Equal amounts of L-tartaric acid and D-tartaric acid are mixed to obtain racemic tartaric acid or DL-tartaric acid. DL-tartaric acid is widely used in food, medicine, chemical industry, light industry and other industries, mainly for the manufacture of tartrates, and in the food industry as beer foaming agent, food sour agent, flavoring agent, and sour age...

AI Technical Summary

Problems solved by technology

[0005] At present, the production process of tartaric acid at home and abroad is a chemical synthesis method, that is, maleic anhydride is used as a raw material, tungsten oxyacid or its salt is used as a catalyst, and hydrogen peroxide is used as an oxidant to prepare epoxysuccinic acid, and then hydrolysis and crystallization Prepare tartaric acid, centrifuge tartaric acid, adjust mother liquor pH value with potassium hydroxide to prepare its hydrogen potassium salt, then separate, mother liquor is sent to waste water pool, this is a relatively ideal route, with few by-products, but the process is not The conversion rate is not high; moreover, the mother liquor contains unreacted raw materials and unreacted maleic acid generated by the direct hydrolysis of the raw materials. If the mother liquor is directly discharged, it will cause waste of resources and increase production costs; meanwhile, it contains heavy metal tungsten The discharge of waste water has also caused serious environmental pollution problems.