Process and device for producing glycine by alcohol phase method

Abstract

The invention relates to a process and a device for producing glycine by an alcohol phase method. The main process comprises the following steps: taking methanol as a solvent, urotropin as a catalystand liquid or solid chloroacetic acid as an initial raw material, firstly introducing ammonia to produce a mixed crystal of glycine and ammonium chloride, centrifuging to obtain a mixed crystal, repeatedly applying the filtrate to synthesis of the mixed crystal, dissolving the mixed crystal by using pure water, extracting a glycine product by using methanol; enabling filtrate after glycine is centrifuged out to enter a rectifying tower to recover methanol, enabling rectified residual liquid to enter a film evaporator, concentrating the rectified residual liquid until water is completely evaporated to directly obtain an ammonium chloride byproduct, and repeatedly using water evaporated from the film evaporator to dissolve mixed crystals. The process mainly uses a glycine synthesis kettle, aglycine extraction kettle, a mixed crystal filtrate elevated tank, a centrifugal machine, a mixed crystal filtrate receiving tank, a chloroacetic acid dissolving kettle, a methanol rectifying tower,a film evaporator, and the like. According to the method, the unit consumption levels of urotropin, liquid ammonia, and steam can be greatly reduced, the production cost is further reduced, and no wastewater is generated.

Description

technical field [0001] The invention discloses a device and process for producing glycine by an alcohol phase method, which belongs to the technical field of chemical production, and in particular relates to a new method for synthesizing glycine by an alcohol phase method and reducing waste water. Background technique [0002] Glycine is aminoacetic acid, as an important fine chemical intermediate and chemical raw material, it is widely used in the fields of pesticide glyphosate, medicine, food and feed additives, etc. At present, the domestic industrialized production process of glycine still adopts the traditional ammonolysis method of chloroacetic acid using water as a solvent. This method has the following problems: (1) High production cost. The catalyst urotropine cannot be recovered; 1 ton of glycine needs to consume about 6-7 tons of steam; the recovery of low-value-added ammonium chloride requires high equipment and pipelines, high maintenance frequency, and high equ...

AI Technical Summary

Problems solved by technology

At present, the domestic industrial production process of glycine still adopts the traditional ammonolysis method of chloroacetic acid with water as the solvent. This method has the following problems: (1) High production cost

The catalyst urotropine cannot be recovered; 1 ton of glycine needs to consume about 6-7 tons of steam; when recovering low value-added ammonium chloride, the requirements for equipment and pipelines are high, the frequency of maintenance is high, and the cost of equipment operation and maintenance is relatively high

(2) Low yield, difficult to break through 85%

The system in the aqueous phase is highly alkaline, and the conversion rate of chloroacetic acid into glycine is low, and about 15% of chloroacetic acid is hydrolyzed to produce glycolic acid; when high temperature ammonia is insufficient, it is easy to produce iminodiacetic acid [NH(CH 2 COOH) 2 ] and aminotriacetic acid [N(CH 2 COOH) 3 ] and other by-products

(3) Environmental risks cannot be completely eliminated

There are defects in this method: (1) The output of the by-product ammonium chloride obtained each time is limited, which affects the output of glycine single-pot production. In order to obtain more ammonium chloride in a single-pot, the organic solvent needs to be refrigerated and cooled, and the energy consumption is relatively low. Big

Images