阅读说明：本技术 一种盐酸胍制备方法 (Preparation method of guanidine hydrochloride ) 是由 方建文 于 2019-10-25 设计创作，主要内容包括：本发明涉及一种化工产品的制备方法,尤其是盐酸胍制备方法,包括下述步骤：a、熔融,b、溶解,c、过滤,d、脱水,e、结晶,盐酸胍成品产率高于95％。反应过程简单,不重复添加原料、加热反应釜以及后续的提纯步骤,同时降低能耗,减少反应时间,大大减少了副产品、提高了收率。(The invention relates to a preparation method of a chemical product, in particular to a preparation method of guanidine hydrochloride, which comprises the following steps: a. melting, b, dissolving, c, filtering, d, dehydrating, e, crystallizing and obtaining the finished guanidine hydrochloride product with the yield higher than 95%. The reaction process is simple, the steps of adding raw materials, heating a reaction kettle and subsequent purification are not repeated, the energy consumption is reduced, the reaction time is shortened, byproducts are greatly reduced, and the yield is improved.)

1. The preparation method of guanidine hydrochloride is characterized by comprising the following steps:

a. melting: adding raw materials of dicyandiamide and ammonium chloride into a reaction kettle according to the weight ratio of 1: 1.27, adding a catalyst of zinc chloride, heating to 165 ℃, preserving heat for 3 hours, and carrying out a melting reaction to obtain a guanidine hydrochloride crude product;

b. dissolving: at normal temperature, dissolving the guanidine hydrochloride crude product in water according to the ratio of 1: 1;

c. and (3) filtering: removing raw materials, catalysts and reaction byproducts by a filtering method;

d. and (3) dehydrating: dehydrating the filtered mother liquor;

e. and (3) crystallization: cooling the supersaturated solution, concentrating and crystallizing to obtain a guanidine hydrochloride finished product;

wherein the input weight of the catalyst zinc chloride is 0.5 percent of the weight of the raw material dicyandiamide, and the weight percentage content of the guanidine hydrochloride in the finished product of the guanidine hydrochloride is more than 95 percent.

2. The method of preparing guanidine hydrochloride according to claim 1, wherein: in the dissolving step, alkali is added into the solution.

Technical Field

The invention relates to a preparation method of a chemical product, in particular to a preparation method of guanidine hydrochloride.

Background

In the existing production process of guanidine hydrochloride, dicyandiamide and ammonium salt (ammonium chloride) are generally used as raw materials, and are subjected to melt reaction at 170-230 ℃ to obtain a guanidine hydrochloride crude product, and the guanidine hydrochloride crude product is refined to obtain a finished product. In the refining process, raw materials need to be added repeatedly, the reaction kettle needs to be heated, and subsequent purification steps need to be carried out, so that the reaction energy consumption and the reaction time are greatly increased, and meanwhile, a large number of byproducts are generated and the yield is low.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects in the prior art, an improved preparation method of guanidine hydrochloride is provided.

The technical scheme adopted by the invention is as follows: a preparation method of guanidine hydrochloride comprises the following steps:

a. melting: adding raw materials of dicyandiamide and ammonium chloride into a reaction kettle according to the weight ratio of 1: 1.27, adding a catalyst of zinc chloride, heating to 165 ℃, preserving heat for 3 hours, and carrying out a melting reaction to obtain a guanidine hydrochloride crude product;

b. dissolving: at normal temperature, dissolving the guanidine hydrochloride crude product in water according to the ratio of 1: 1;

c. and (3) filtering: removing raw materials, catalysts and reaction byproducts by a filtering method;

d. and (3) dehydrating: dehydrating the filtered mother liquor;

e. and (3) crystallization: cooling the supersaturated solution, concentrating and crystallizing to obtain a guanidine hydrochloride finished product;

wherein the input weight of the catalyst zinc chloride is 0.5 percent of the weight of the raw material dicyandiamide, and the weight percentage content of the guanidine hydrochloride in the finished product of the guanidine hydrochloride is more than 95 percent.

In the melting step, after heating to 165 ℃, the heating is stopped, the reaction is carried out for 3 hours, and the temperature is increased from 165 ℃ to 185 ℃. The melting reaction temperature is up to 185 ℃, and side reaction is difficult to occur at the temperature, so that byproducts are greatly reduced, and the yield is improved.

In the dissolving step, alkali is added into the solution so as to treat the residual ammonium salt in the reaction.

Compared with the prior art, the invention has the following advantages: the reaction process is simple, the steps of adding raw materials, heating a reaction kettle and subsequent purification are not repeated, the energy consumption is reduced, the reaction time is reduced, the reaction temperature is up to 185 ℃, byproducts are greatly reduced, and the yield is improved.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the embodiments of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1

A preparation method of guanidine hydrochloride comprises the following steps:

a. melting: adding raw materials of dicyandiamide and ammonium chloride into a reaction kettle according to the weight ratio of 1: 1.27, adding a catalyst of zinc chloride, heating to 165 ℃, preserving heat for 3 hours, and carrying out a melting reaction to obtain a guanidine hydrochloride crude product;

b. dissolving: at normal temperature, dissolving the guanidine hydrochloride crude product in water according to the ratio of 1: 1;

c. and (3) filtering: removing raw materials, catalysts and reaction byproducts by a filtering method;

d. and (3) dehydrating: dehydrating the filtered mother liquor;

e. and (3) crystallization: cooling the supersaturated solution, concentrating and crystallizing to obtain a guanidine hydrochloride finished product;

wherein the input weight of the catalyst zinc chloride is 0.5 percent of the weight of the raw material dicyandiamide, and the weight percentage content of the guanidine hydrochloride in the finished product of the guanidine hydrochloride is more than 95 percent.

In the melting step, heating was stopped after heating to 165 ℃ and the reaction was stopped for 3 hours, and the temperature was raised from 165 ℃ to 185 ℃.

In the dissolving step, an alkali is added to the solution.