Production process of acid-sensitive phosphite

Abstract

The invention relates to production process of phosphite, and belongs to the technical field of chemical production. The process provided by the invention is characterized in that phosphite is synthesized by taking tertiary amine as acid-binding agent and solvent, and comprises the following steps: sequentially treating a crude product with dilute alkali, concentrated alkali and solid alkali, recovering triethylamine, drying, dewatering to obtain a triethylamine solution of the product, and finally distilling to recover the triethylamine and obtain the product. According to the invention, the process can favorably protect the phosphite from acidolysis and hydrolysis, and is mild in process conditions and high in product yield; synthesis and alkali washing can be performed at a temperature near room temperature, thereby avoiding low-temperature operation; industrially available room temperature circulating water is used instead of freezing saline water, there obviously saving energy and reducing consumption; and the process realizes the best use of the raw materials, is convenient to manage and is applicable to industrial production.

Description

technical field [0001] The invention belongs to the technical field of chemical production, and in particular relates to a production process of acid-sensitive phosphite. Background technique [0002] Phosphites are widely used, especially trimethyl phosphite and triethyl phosphite, which can be used to manufacture plasticizers, flame retardants, pesticides, medicines, rare metal extractants, organic synthesis intermediates, etc. [0003] Phosphite is generally produced by the reaction of alcohol and phosphorus trichloride. The reaction formula is shown in (1). The reaction between the two is very violent, even at low temperature. [0004] PCl 3 +3ROH=(RO) 3 P+3HCl+Q 1 (1) [0005] Where: R=CH 3 , C 2 h 5 . [0006] As can be seen from the reaction (1) formula, every reaction of 1 mole of phosphorus trichloride will generate 3 moles of hydrogen chloride (HCl). Hydrogen chloride is an acidic gas, and its presence will degrade phosphite, especially the phosphite of l...

AI Technical Summary

Problems solved by technology

[0016] There are some deficiencies in the traditional process, mainly as follows: (1) the amount of triethylamine is less and the amount of aromatic hydrocarbon solvent is a lot, and hydrogen chloride is generated while generating phosphite, that is, the hydrogen chloride molecule is near the product molecule. During the reaction of amine molecules looking for hydrogen chloride molecules, hydrogen chloride has already degraded part of the product, resulting in a decrease in yield; (2) the synthesis reaction must be carried out at low temperature to reduce the acidolysis of the product, and the post-treatment alkali washing must also be performed at low temperature The hydrolysis of the product can be reduced only if the product is hydrolyzed at low temperature. The low temperature operation consumes more energy and the operating cost is higher; (3) the dehydration is not complete. When the subsequent process is heated, the residual moisture will cause part of the product to be hydrolyzed, which will also reduce the yield.