Preparation method of diethyl phosphinic acid without monoethyl phosphinic acid group and salt thereof

Abstract

The invention relates to the field of fine organic chemical industry and polymer materials, and particularly relates to a preparation method of diethyl phosphinic acid without monoethyl phosphinic acid group and salt thereof. The preparation method of diethyl phosphinic acid comprises the following steps: uniformly mixing sodium hypophosphite monohydrate, acetic anhydride and organic solvent; adding organic acid and concentrated sulfuric acid or anhydrous sulfuric acid; cooling and standing; filtering and recovering sodium sulfate to obtain an anhydrous phosphinic acid organic acid solution; adding ethylene and dropwise adding a trigger mixture to obtain a first mixture; and distilling and recovering the organic acid and the organic solvent to obtain a product. The preparation method is simple and easy to implement, the monoethyl phosphinic acid is completely converted into diethyl phosphinic acid, and the prepared diethyl phosphinic acid does not contain the monoethyl phosphinic acid group. In the invention, the diethyl phosphinic acid without the monoethyl phosphinic acid group serves as a reactant and reacts with a metal compound, the obtained diethyl phosphinate does not contain impurities such as organic sodium salt, and the generated waste liquid is simple to dispose.

Description

technical field [0001] The invention relates to the fields of fine organic chemical industry and macromolecular materials, in particular to a preparation method of diethylphosphinic acid and its salts without monoethylphosphinic acid groups. Background technique [0002] Diethylphosphinic acid and salts thereof that do not contain monoethylphosphinic acid groups have the structural characteristics of the following formulas (I) and (II): [0003] [0004] R in the formulas (I) and (II) 1 and R 2 Both are ethyl, n in formula (II) is 1-4, M is aluminum, zinc, magnesium, antimony, scandium, yttrium, titanium, zirconium, vanadium, niobium, chromium, molybdenum, manganese, iron, cobalt, nickel , cadmium, germanium, tin, lanthanum, pavement, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and other metal ions. [0005] The product density of this kind of flame retardant is low, the amount of addition is small whe...

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Problems solved by technology

Chinese patent CN101624401 A reports a method for preparing dialkylphosphine by free radical reaction between olefin and phosphine under the action of an initiator, and then preparing dialkylphosphinic acid through oxide oxidation and other processes. The cost is high, and there is no report on the preparation of dialkylphosphinic acid and its salts by alkylation of light olefins and phosphine

Chinese patent CN101048344 A reports the method of removing monoalkylphosphinic acid salts by alkali washing to achieve purification of dialkylphosphinic acid and its salts. In 2011, Yang Li of Nankai University reported in "Chemical Reagents" that the method used in strong acid conditions The following methods for preparing aluminum diethylphosphinate with higher purity, there is no detailed data on aluminum diethylphosphinate, both methods are resolved during post-processing and the product does not contain mono-alkylphosphinate According to the report of Chinese patent CN101891762 A jointly applied by Yang Li and others, there is no solution to remove the method of monoalkylphosphinic acid or monoalkylphosphinate

But so far, there are still two problems in this method, one is to contain a certain amount of monoethylphosphinate in the prepared diethylphosphinate; Contains a large amount of organic sodium salt, and produces a large amount of wastewater containing organic sodium salt in the process of preparing diethylphosphinate

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