Preparation method of isobutyl 3,5-diamino-4-chlorobenzoate

Abstract

A preparation method of isobutyl 3,5-diamino-4-chlorobenzoate comprises the following basic steps: step 1, putting raw material ester compound, a solvent, a catalyst Raney nickel and a dehalogenation inhibitor into a high pressure reaction kettle at one time, sealing, and adopting 0.2-0.3 MPa of nitrogen gas and hydrogen gas for replacing gas in the high pressure reaction kettle for 3 times respectively; step 2, after completely sealing in the step 1, adding the hydrogen gas pressure to 3.0 MPa, increasing the temperature of the high pressure reaction kettle, carrying out a reaction, and timely replenishing the hydrogen gas pressure to ensure that the pressure in the high pressure reaction kettle in the reaction process is maintained at 3.0 MPa; step 3, adding hydrogen gas to maintain the pressure at 3.0 MPa in the step 2, carrying out a reaction for about 1.5-2 hours, finishing the reaction after the system absorbs hydrogen gas no longer, and overall cooling; step 4, after the step 3 is finished, recycling the catalyst Raney nickel; step 5, carrying out reduced pressure concentration of a filtrate to be viscous, putting into a refrigerator, and cooling and crystallizing at low temperature; and step 6, desolventizing the solvent alcohol and the dehalogenation inhibitor, recycling and reusing. The method is low in cost, safe and feasible.

Description

technical field

[0001] The invention relates to a method for preparing chemical raw materials, in particular to a method for preparing isobutyl 3,5-diamino-4-chlorobenzoate. Background technique

[0002] 3,5-diamino-4-chlorobenzoic acid isobutyl ester is a kind of organic acid ester chemical additive with promising market prospect, its molecular formula C 11 h 15 N 2 o 2 Cl, molecular weight 242.5, brown crystalline powder under normal temperature and pressure, avoid contact with oxidants during storage, easily soluble in alcohols, ethers, carbon tetrachloride, methylene chloride and other organic solvents, insoluble in water, mainly used for Polyurethane chain extender or chain extender, the traditional production process uses p-chlorobenzoic acid as raw material to obtain dinitro-p-chlorobenzoic acid through nitration under the action of sulfuric acid, and undergoes esterification reaction with isobutanol through sulfuric acid catalysis, and the obtained esterified prod...

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