CN1775358A

CN1775358A - Method for preparing N-substituted carbamate using cyclohexane zine butyrate

Info

Publication number: CN1775358A
Application number: CN 200510048150
Authority: CN
Inventors: 孙予罕; 肖福魁; 魏伟; 赵宁; 李军平; 张德胜; 徐宏; 姚玉媛; 陈志明; 孙继德
Original assignee: Shanxi Institute of Coal Chemistry of CAS
Current assignee: Shanxi Institute of Coal Chemistry of CAS
Priority date: 2005-12-01
Filing date: 2005-12-01
Publication date: 2006-05-24
Anticipated expiration: 2025-12-01
Also published as: CN100369671C

Abstract

The present invention relates to method for preparing N-substituted carbamate by using zinc cyclohexane butyrate. Said method is characterized by that the zinc cyclohexane butyrate catalyst, amino compound and organic carbonate are mixed, their added quantity is as follows: amino compound: organic carbonate mole ratio is 10-40:1, mass ratio of zinc cyclohexane butyrate: amino compound is 0.05-0.5:1, under the condition of that reaction temperature is 90-200deg.C and reaction pressure is 0.2-1.0MPa they are reacted for 2-12hr. so as to obtain the invented catalyst.

Description

Method for preparing N-substituted carbamate by using zinc cyclohexanebutyrate

Technical Field

The invention belongs to a method for preparing N-substituted carbamate, and particularly relates to a method for preparing N-substituted carbamate by using zinc cyclohexanebutyrate.

Background

The N-substituted carbamate is a very important organic intermediate, can be widely used for synthesizing agricultural chemicals, dyes, medicines, urea compounds and corresponding various isocyanate products, and can also be used as a protecting group of amino in various organic synthesis processes. Industrially, N-substituted carbamates are usually prepared by reacting alcohols with isocyanates or amines with chloroformates, which are obtained by reacting highly toxic phosgene with the corresponding amines or the corresponding hydroxyl compounds. It can be said that the current industrial process for preparing N-substituted carbamates is actually an indirect phosgene process. With the knowledge of the relationship between resources, environment and sustainable development in all world, people are strongly demanding to establish a clean production-ecological economy new process which is friendly to the environment so that the human society can develop healthily and continuously. The use of highly toxic phosgene clearly contradicts this theme. The method for preparing the N-substituted carbamate by using the green nontoxic or low toxic organic carbonate as the alkoxy carbonylation reagent to react with the amino compound is a feasible process route for preparing the N-substituted carbamate without phosgene.

In the preparation of N-substituted carbamates by reacting aromatic amines with organic carbonates, U.S. Pat. No. 3,763,217 proposes the use of AlCl₃、FeCl₃、UO₂(NO)₂When Lewis acid is used as a catalyst for the reaction, the yield of the corresponding N-substituted carbamate is about 20 percent under the reflux condition. U.S. Pat. No. 4,268,683 proposes the use of zinc salts of organic acids having pKa values greater than 2.8, such as zinc acetate, zinc propionate, and naphthaleneThe zinc salt is used as the catalyst of the reaction, so that the yield of the mono-N-substituted carbamate can reach about 70 percent, but the catalytic effect on diamino derivatives of aromatic hydrocarbon is poor, and the yield of the di-N-substituted carbamate is about 18 to 36 percent. U.S. Pat. No. 4,268,684 proposes the use of anhydrous or dihydrate zinc acetate in the preparation of 4, 4 '-methylenediphenyl di-N-substituted carbamate (MDC) by reaction of 4, 4' -Methylenedianiline (MDA) with dimethyl carbonate, with a conversion of MDA of more than 99% and a selectivity of MDC of more than 97% after 1.5 hours at 140 ℃, and U.S. Pat. No. 5,688,988 proposes the use of basic carbonates of Zn or Cu as catalyst, with a selectivity of MDC of 98% and a yield of MDC of 97.5% by reacting MDA with DMC for 6 hours at 180 ℃ under 4.5 atm. In the process of preparing isophorone diisocyanate (IPDI), U.S. Pat. No. 5,789,614 use sodium methoxide as a catalyst, isophorone diamine (IPDA) and dimethyl carbonate react at 70 ℃ for 3 hours, and the yield of isophorone diamino methyl formate (IPDC) is 99.5%. However, the reaction is carried out under anhydrous conditions, since water deactivates the catalyst. Pat.5,698,731 uses N_xO_y(OCONR’)_zThe catalyst of the form wherein x 1-4 is an integer, y is an integer of 0-1, z is an integer of 1-6, R' represents C₁～C₁₂Straight or branched alkyl or C₅～C₇Cycloalkyl or aralkyl radicals for catalysing the reaction of TDA with MDA and conversion of the corresponding 2, 4-diaminotolueneThe ratio is 79-99%, and the selectivity of 2, 4-toluene dicarbamate is 63-99%. WO98/55450 supports zinc organic acid such as zinc acetate and zinc 2-ethylhexanoate on TiO₂，Al₂O₃Or SiO₂And (3) catalyzing MDA and DMC to react at 180 ℃ on an inert carrier (the weight percentage of zinc is 6 wt%), converting MDA 100% after 2 hours, and enabling the selectivity of MDC to reach 96.3%.

One disadvantage of the above catalysts is that the selectivity of the desired product during the reaction is not very good and that the catalytic activity of some catalysts is limited by the type of amino compound.

Disclosure of Invention

The invention aims to provide a method for preparing aryl carbamate by using zinc cyclohexanebutyrate with wide application range and good catalytic activity in the reaction of amino compounds and organic carbonates.

The zinc cyclohexanebutyrate catalyst used in the present invention comprises zinc cyclohexanebutyrate dihydrate or anhydrous zinc cyclohexanebutyrate

The catalyst of the present invention is suitable for the following reactions:

mixing the catalyst, the amino compound and the organic carbonate, wherein the adding amount is as follows: the mol ratio of the organic carbonate is 10-40: 1, the mass ratio of the catalyst to the amino compound is 0.05-0.5: 1, and the reaction temperature is 90-200 ℃; the reaction is carried out under the condition that the reaction pressure is 0.2-1.0 Mpa for 2-12 hours.

The amino compounds mentioned above are: and amino compounds such as hexamethylenediamine, octylamine, aniline, 4-chloroaniline, p-toluidine, 2, 4 ' -diamino-diphenylmethane, 3, 4-dichloroaniline, 2, 2 ' -diamino-diphenylmethane, 4 ' -diamino-diphenylmethane, 1, 5-naphthalene-diamine, 1, 8-naphthalene-diamine, 2, 6-dinaphthylamine, 2, 4-toluenediamine, 2, 6-toluenediamine, and polyaminopolyphenyl methane.

The organic carbonates as mentioned above are: carbonate compounds such as ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate, diphenyl carbonate, methylphenyl carbonate, dipropyl carbonate, and dibutyl carbonate.

The invention has the following advantages:

1) the catalyst is a chemical product and is easy to purchase.

2) The catalyst has high activity, less consumption and good selectivity of target products.

Detailed Description

Example 1:

in an 80ml autoclave, 10g of 4, 4' -diamino-diphenylmethane (50.5mmol), 45.5g (505mmol) of dimethyl carbonate and 0.1g of anhydrous zinc cyclohexanebutyrate catalyst were charged, the atmosphere in the autoclave was replaced with high-purity nitrogen gas for 5 minutes, and then the temperature was raised to 90 ℃ with stirring, the pressure in the autoclave was adjusted to 0.2MPa with nitrogen gas, and the reaction was carried out for 12 hours. After the reaction, the excess dimethyl carbonate was distilled off, then N, N-Dimethylformamide (DMF) was added to the residue to dissolve the reaction product, the catalyst was removed by filtration, and analysis was performed by high performance liquid chromatography, and the conversion of 4, 4' -diamino-diphenylmethane was 100%, and the selectivity of the corresponding aryl carbamate was 99.75%.

Example 2

The amounts of the starting materials and the catalyst charged were the same as in example 1, and the conversion of 4, 4' -diamino-diphenylmethane was 100% and the selectivity for the corresponding aryl carbamate was 99.31% at 145 ℃ and 0.5MPa for 6 hours of the reaction.

Example 3

The amounts of the starting materials and the catalyst charged were the same as in example 1, and the conversion of 4, 4' -diamino-diphenylmethane was 100% and the selectivity for the corresponding aryl carbamate was 95.82% at 200 ℃ and 1MPa for 2 hours.

Example 4

5g of 1, 5-naphthalenediamine (31.6mmol), 56.88g (632mmol) of dimethyl carbonate and 1.27g of zinc cyclohexanebutyrate dihydrate catalyst were charged into an 80-ml autoclave, the temperature was raised to 160 ℃ and the pressure in the autoclave was adjusted to 0.8MPa with nitrogen gas, and the reaction was carried out for 5 hours with a conversion of 1, 5-naphthalenediamine of 100% and a selectivity of the corresponding arylcarbamate of 99.03%.

Example 5

2.5g of 1, 5-naphthalenediamine (15.8mmol), 56.88g (632mol) of dimethyl carbonate and 1.27g of a catalyst were charged into an 80ml autoclave, the temperature was raised to 160 ℃ and the pressure in the autoclave was adjusted to 1MPa with nitrogen gas, and the reaction was carried out for 2 hours with a conversion of 1, 5-naphthalenediamine of 100% and a selectivity of the corresponding aryl carbamate of 99.01%.

Example 6

10g of aniline (107.5mmol), 19.35g (215mol) of dimethyl carbonate and 5g of anhydrous zinc cyclohexanebutyrate catalyst are added into an 80ml autoclave, the temperature is raised to 120 ℃, the pressure in the autoclave is adjusted to 0.4MPa by nitrogen, the reaction is carried out for 8 hours, the conversion rate of the aniline is 100 percent, and the selectivity of the corresponding aryl carbamate is 99.68 percent.

Example 7

2.5g of 2, 4-toluenediamine (20.49mmol), 55.32g (614.67mmol) of dimethyl carbonate and 0.5g of a catalyst were charged into an 80ml autoclave, the atmosphere in the autoclave was replaced with high-purity nitrogen for 5 minutes, and then the temperature was raised to 170 ℃ with stirring, and the pressure in the autoclave was adjusted to 0.9MPa with nitrogen, and the reaction was carried out for 4 hours. After the reaction, the excess dimethyl carbonate was distilled off, then N, N-Dimethylformamide (DMF) was added to the residue to dissolve the reaction product, the catalyst was removed by filtration, and the conversion of 2, 4-toluenediamine was 100% and the selectivity of the corresponding aryl carbamate was 98.49% by high performance liquid chromatography.

Claims

1. A method for preparing N-substituted carbamate by using zinc cyclohexanebutyrate, which is characterized by comprising the following steps:

mixing zinc cyclohexanebutyrate catalyst, an amino compound and an organic carbonate in the following amounts: the organic carbonate molar ratio is 10-40: 1, and the cyclohexane zinc butyrate catalyst is: the mass ratio of the amino compound is 0.05-0.5: 1, and the reaction temperature is 90-200 ℃; the reaction is carried out under the condition that the reaction pressure is 0.2-1.0 Mpa for 2-12 hours.

2. The method of claim 1, wherein the zinc cyclohexanebutyrate is zinc cyclohexanebutyrate dihydrate or anhydrous.

3. The method for producing N-substituted carbamic acid ester using zinc cyclohexanobutyrate according to claim 1, wherein the amino compound is hexamethylenediamine, octylamine, aniline, 4-chloroaniline, p-toluidine, 2, 4 ' -diamino-diphenylmethane, 3, 4-dichloroaniline, 2, 2 ' -diamino-diphenylmethane, 4 ' -diamino-diphenylmethane-1, 5-naphthalene-diamine, 1, 8-naphthalene diamine, 2, 6-dinaphthylamine, 2, 4-toluene diamine, 2, 6-toluene diamine or polyaminopolyphenyl methane. 4. The method according to claim 1, wherein the organic carbonate is ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate, diphenyl carbonate, methylphenyl carbonate, dipropyl carbonate or dibutyl carbonate.