阅读说明：本技术 一种苯二胺及苯二胺无机盐的制备方法 (Preparation method of phenylenediamine and phenylenediamine inorganic salt ) 是由 王植源 王天露 于 2020-07-20 设计创作，主要内容包括：本发明公开了一种苯二胺及苯二胺无机盐的制备方法。所述苯二胺的制备方法,包括：步骤(1)：苯二酸酯与羟胺反应得到苯二酰异羟肟酸或苯二酰异羟肟酸盐；步骤(2)：所述苯二酰异羟肟酸或苯二酰异羟肟酸盐发生重排反应,得到所述苯二胺。本发明以苯二酸酯为起始原料,不使用硝化和还原反应,消除废酸污染和多硝基苯易爆的隐患。(The invention discloses a preparation method of phenylenediamine and phenylenediamine inorganic salt. The preparation method of the phenylenediamine comprises the following steps: step (1): reacting phthalate ester with hydroxylamine to obtain phthalic hydroxamic acid or phthalic hydroxamate; step (2): and (3) carrying out rearrangement reaction on the benzene diacid hydroxamic acid or the benzene diacid hydroxamate to obtain the phenylenediamine. The invention takes phthalate ester as an initial raw material, does not use nitration and reduction reaction, and eliminates the hidden troubles of waste acid pollution and polynitrobenzene explosion.)

1. A preparation method of phenylenediamine and inorganic salt thereof is characterized by comprising the following steps:

step (1): reacting phthalate ester with hydroxylamine to obtain phthalic hydroxamic acid or phthalic hydroxamate;

step (2): the benzenedicarboxylic acid hydroxamic acid or benzenedicarboxylic acid hydroxamate is subjected to rearrangement reaction, feed liquid after the rearrangement reaction is subjected to neutralization reaction to obtain the benzenediamine, or the feed liquid after the rearrangement reaction is subjected to acidification reaction to obtain the benzenediamine inorganic salt.

2. The method for preparing phenylenediamine according to claim 1, wherein said phenylenediamine is m-phenylenediamine or p-phenylenediamine.

3. The method for preparing phenylenediamine and an inorganic salt thereof according to claim 1, wherein in the step (1), said phthalic ester is a C1-C12 alkyl ester of isophthalic acid or a C1-C12 alkyl ester of terephthalic acid, preferably a methyl or ethyl ester of isophthalic acid or a methyl or ethyl ester of terephthalic acid, more preferably dimethyl isophthalate or dimethyl terephthalate;

preferably, the hydroxylamine hydrochloride is neutralized by inorganic base to prepare the hydroxylamine; more preferably, the inorganic base is a hydroxide of sodium, potassium, barium, cesium; more preferably, the benzenedicarboxhydroxamate is an inorganic salt of benzenedicarboxhydroxamic acid.

4. The method for preparing phenylenediamine and its inorganic salts according to claim 1, wherein in said step (1), said reaction time is 2 to 24 hours, and the reaction temperature is 0 to 40 ℃;

preferably, in the step (1), the molar ratio of the phthalate ester to the hydroxylamine is 1.0: 2.0-1.0: 2.5;

preferably, in the step (1), the reaction of the phthalate ester with hydroxylamine is performed in an alcohol solution;

preferably, after the reaction of the phthalate ester with the hydroxylamine, the solvent is removed directly, followed by washing with methanol-water to give the corresponding potassium salt of benzenedicarboxyl hydroxamate.

5. The process for producing phenylenediamine and inorganic salts thereof according to claim 1, wherein in said step (2), said rearrangement reaction is a Rosson rearrangement reaction; preferably, the temperature of the rearrangement reaction is 80-200 ℃, more preferably 100-150 ℃;

preferably, the time of the rearrangement reaction is 1 to 24 hours.

6. The process for producing phenylenediamine and its inorganic salts according to claim 1, wherein in said step (2), said rearrangement reaction is carried out in the presence of a reaction solvent; more preferably, the rearrangement reaction is also carried out in the presence of a catalyst.

7. A process for the preparation of phenylenediamine and its inorganic salts according to claim 6, wherein said reaction solvent is a mixture of a nitrile compound and water, preferably in a volume ratio of 10:1 to 1:10, more preferably 1.5: 1; more preferably, the nitrile compounds are acetonitrile, butyronitrile, benzonitrile and adiponitrile, preferably acetonitrile.

8. Process for the preparation of phenylenediamine and its inorganic salts according to claim 6, wherein said catalyst is a hydroxide and/or carbonate of sodium, potassium, barium, cesium, preferably cesium carbonate.

9. The process for producing phenylenediamine and its inorganic salts according to claim 6, wherein in said step (2), said rearrangement reaction is carried out under normal pressure in the presence of said catalyst;

preferably, in the step (2), a phenylenediamine separation step and a reaction solvent removal step are further included after the neutralization reaction, and more preferably, the separation step is extraction with ethyl acetate; and the reaction solvent is removed by evaporating.

10. The method for preparing phenylenediamine and its inorganic salts according to claim 1, wherein in said step (2), said acidification reaction is carried out with an inorganic acid to a pH of 1 to 2; preferably, the inorganic acid is hydrochloric acid.

Technical Field

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of phenylenediamine and phenylenediamine inorganic salt.

Background

The phenylenediamine, including p-phenylenediamine and m-phenylenediamine, is an important organic chemical raw material and intermediate, is used for preparing polyimide, aramid fiber, dye, rubber anti-aging agent, petroleum product additive, flame retardant, epoxy resin curing agent, cement coagulant, petroleum additive, raw material for medical synthesis and the like, and has wide application.

The main production process of p-phenylenediamine uses chlorobenzene as initial raw material, and utilizes mixed acid nitration and ammonolysis to obtain p-nitroaniline, and then reduces nitro group so as to obtain the p-phenylenediamine. The traditional production process of m-phenylenediamine takes benzene as a raw material, and a final product is obtained by high-temperature nitration and reduction of mixed acid. The mixed acid nitration reaction is easy to generate danger, and the excessive nitrated polynitro byproduct is easy to explode.

At present, nitro groups are reduced by three main methods, namely iron powder reduction, alkali sulfide reduction and hydrogenation reduction. The iron powder reduction method has the disadvantages of laggard production technology, more three wastes, serious environmental pollution, low yield and high cost (Shanxi chemical industry, 2003, 23(2), 22-24). The sodium sulfide reduction method has the advantages of mature and stable technology, good product quality, high safety and low cost, but the conversion rate of the paranitroaniline is not high, and the paranitroaniline still remains solid waste. The hydrogenation reduction method has advanced technology, good product quality, low cost and less three wastes, and is the most environment-friendly and efficient method at present. For example, m-phenylenediamine (CN 108164425; CN107540554) and p-phenylenediamine (CN 1594278A; CN108658781A) can be produced by hydrogenation reduction based on various metal catalysts.

In order to solve the problems of complexity in the synthetic route of p-phenylenediamine and serious pollution in the nitration process, Chinese patent CN1116619 discloses a method for synthesizing p-phenylenediamine by using aniline as a starting material. Diazotizing aniline with nitrous acid, heating for rearrangement, separating to obtain p-aminoazobenzene, and carrying out catalytic hydrogenation reduction reaction to generate p-phenylenediamine. Chinese patent CN110818572A discloses a three-step synthesis method, which comprises the steps of separating diazo coupling product 1, 3-diphenyltriazene and transposition rearrangement product 4-aminoazobenzene respectively, and then carrying out hydrogenation reduction reaction to obtain a p-phenylenediamine product. The diazotization needs to use a large amount of hydrochloric acid and sodium nitrite, and inevitably generates waste acid and waste solid.

In order to solve the problems of high temperature, high risk, environmental pollution and the like of the traditional process of the m-phenylenediamine, Chinese patents CN110437080A and CN111100012A respectively disclose a method for preparing the m-phenylenediamine by carrying out Hofmann rearrangement reaction on m-phthalic diamide and sodium hypochlorite. The method avoids the mixed acid nitration process, but still faces the problem of safe use of a large amount of sodium hypochlorite oxidant and highly toxic chlorine.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide the preparation method of phenylenediamine, which is safe, clean and efficient, does not use nitration and reduction reaction, and can eliminate the hidden troubles of waste acid pollution and polynitrobenzene explosion.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a method for preparing phenylenediamine and inorganic salts thereof comprises the following steps:

step (1): reacting phthalate ester with hydroxylamine to obtain phthalic hydroxamic acid or phthalic hydroxamate;

step (2): the benzenedicarboxylic acid hydroxamic acid or benzenedicarboxylic acid hydroxamate is subjected to rearrangement reaction, feed liquid after the rearrangement reaction is subjected to neutralization reaction to obtain the benzenediamine, or the feed liquid after the rearrangement reaction is subjected to acidification reaction to obtain the benzenediamine inorganic salt.

In the above-mentioned method for producing phenylenediamine, as a preferred embodiment, the phenylenediamine is m-phenylenediamine or p-phenylenediamine.

In the above method for preparing phenylenediamine, as a preferred embodiment, in the step (1), the phthalic ester is a C1-C12 alkyl ester of isophthalic acid or a C1-C12 alkyl ester of terephthalic acid, preferably a methyl or ethyl ester of isophthalic acid or a methyl or ethyl ester of terephthalic acid, and more preferably dimethyl isophthalate or dimethyl terephthalate.

In the above-mentioned process for producing phenylenediamine, as a preferable embodiment, in the step (1), the hydroxylamine is produced by neutralizing hydroxylamine hydrochloride with an inorganic base; more preferably, the inorganic base is a hydroxide of sodium, potassium, barium, cesium; preferably, the benzenedicarboxhydroxamate is an inorganic salt of benzenedicarboxhydroxamic acid.

In the above process for producing phenylenediamine, as a preferred embodiment, in the step (1), the reaction time is 2 to 24 hours and the reaction temperature is 0 to 40 ℃.

In the above method for preparing phenylenediamine, as a preferred embodiment, in the step (1), the molar ratio of the phthalate ester to hydroxylamine is 1.0:2.0 to 1.0: 2.5.

In the above-mentioned method for preparing phenylenediamine, as a preferred embodiment, in the step (1), the reaction of the phthalic ester with hydroxylamine is carried out in an alcohol-water solution;

in the step (1), after the reaction of the phthalate ester and the hydroxylamine, the solvent is directly removed, and the reaction product is washed by a small amount of methanol-water to obtain the corresponding potassium benzenedicarboxyl hydroxamate, which can be used for the reaction in the step (2) without further purification.

The benzenedicarboxyl hydroxamic acid in the step (1) of the invention is obtained by post-treating potassium terephthalamide hydroxamate, and the post-treatment specifically comprises the following steps: acidifying potassium benzenedicarboxhydroxamate with hydrochloric acid until the pH value is 5, reacting for 3h under stirring, standing for more than 48h, filtering to obtain a precipitate, washing the precipitate with ethanol, and drying to obtain the benzenedicarboxhydroxamic acid.

In the above-mentioned process for producing phenylenediamine, as a preferred embodiment, in the step (2), the rearrangement reaction is a larsen rearrangement reaction; preferably, the temperature of the rearrangement reaction is 80-200 ℃ (e.g., 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃), preferably 100-; if the reaction temperature is too low, the reaction yield is low, and if the reaction temperature is too high, the pressure in the reaction kettle is too high, and the operation is not suitable.

In the above process for producing phenylenediamine, as a preferred embodiment, in the step (2), the time of the rearrangement reaction is 1 to 24 hours.

In the above-mentioned process for producing phenylenediamine, as a preferred embodiment, in the step (2), the rearrangement reaction is carried out in the presence of a reaction solvent; more preferably, the rearrangement reaction is also carried out in the presence of a catalyst.

In the above-mentioned method for producing phenylenediamine, as a preferable embodiment, in the step (2), the reaction solvent is a mixture of a nitrile compound and water, and preferably, the volume ratio of the nitrile compound to water is 10:1 to 1:10 (for example, 9:1, 7:1, 5:1, 3:1, 1:3, 1:5, 1:7, 1:9), preferably 1.5: 1; more preferably, the nitrile compounds are acetonitrile, butyronitrile, benzonitrile and adiponitrile, preferably acetonitrile; the water is helpful for dissolving the raw materials, the solubility of the water is better than that of acetonitrile, if the water amount is too small, the raw materials cannot be fully dissolved, and the reaction is slow; nitrile compounds such as acetonitrile and the like are activators of rearrangement reaction, and if the proportion of the nitrile compounds is too low, the nitrile compounds can also cause non-reaction or too slow reaction and the like; the amount of the reaction solvent is such that activation and dissolution of the reaction substance are ensured to facilitate the reaction, and preferably, the reaction solvent is in excess, particularly, the nitrile compound is in excess in the reaction solvent. More preferably, the weight to volume ratio of the benzenedicarboxhydroxamic acid or benzenedicarboxhydroxamic acid salt to the nitrile compound is 1:2 to 1: 25.

The weight-to-volume ratio mentioned in the present invention is in g as a unit of weight and in mL as a unit of volume.

In the above process for producing phenylenediamine, as a preferred embodiment, in the step (2), the catalyst is a hydroxide and/or carbonate of sodium, potassium, barium, cesium, preferably cesium carbonate.

In the above process for producing phenylenediamine, as a preferred embodiment, in the step (2), the rearrangement reaction is carried out under a pressure condition of 0.1 to 1.6 MPa.

In the above-mentioned process for producing phenylenediamine, as a preferred embodiment, in the step (2), the rearrangement reaction is carried out under normal pressure in the presence of the catalyst; the presence of the catalyst allows the rearrangement reaction to be carried out at reduced temperatures and at atmospheric pressure, which makes it easier to operate, less demanding on equipment and less costly.

In the above method for producing phenylenediamine, as a preferred embodiment, in the step (2), a phenylenediamine separation step and a reaction solvent removal step are further included after the neutralization reaction, and more preferably, the separation step is extraction with ethyl acetate; and the reaction solvent is removed by evaporating.

In the above process for producing phenylenediamine, as a preferred embodiment, the reaction equation in the step (1) is as follows:

the reaction equation in the step (2) is as follows:

in the above-mentioned method for producing an inorganic salt of phenylenediamine, as a preferred embodiment, in the step (2), the acidification with an inorganic acid is carried out to a pH of 1 to 2.

In the above method for producing an inorganic salt of phenylenediamine, as a preferred embodiment, the inorganic acid is hydrochloric acid.

Compared with the prior art, the invention has the following beneficial effects:

(1) the phthalate ester is used as an initial raw material, and nitration and reduction reactions are not used, so that the hidden troubles of waste acid pollution and polynitrobenzene explosion are eliminated.

(2) The phenylenediamine prepared by the method has higher yield.

Drawings

FIG. 1 shows an infrared spectrum (KBr) of p-phenylenediamine obtained in example 8 of the present invention.

Detailed Description

In order to highlight the objects, technical solutions and advantages of the present invention, the present invention is further illustrated by the following examples, which are presented by way of illustration of the present invention and are not intended to limit the present invention. The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.