A method for preparing hydroxylamine hydrochloride from cyclohexanone oxime

Abstract

The present invention proposes a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime, and belongs to the field of organic chemistry technology.Cyclohexanone oxime, water, catalyst and hydrochloric acid are uniformly mixed, reacted by heating, and reaction solution is extracted three times with toluene, and the raffinate aqueous phase is placed in a low-temperature reaction bath, neutralized, and after pH value is 6.0 7.0, precipitate is removed by filtration under reduced pressure, and the filter cake is washed with deionized water three times, and the filtrate obtained obtains hydroxylamine hydrochloride crude product through rotary evaporation, and the crude product is washed and vacuum-dried, and hydroxylamine hydrochloride can be obtained. The present invention prepares a kind of efficient catalyst, is a kind of solid acid immobilized porous silica catalyst, can efficiently catalyze cyclohexanone oxime hydrolysis, catalytic efficiency is high, and the conversion rate and yield of obtained hydroxylamine hydrochloride are higher, and side reaction is few, and product purity is high, with broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemistry, and in particular to a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. Background Art

[0002] Hydroxylamine and its salts are important chemical raw materials. The main industrial synthesis methods for hydroxylamine salts include the Raschig method, NO catalytic reduction, nitrate ion reduction, and nitroalkane hydrolysis. Hydroxylamine can also be produced by hydrolysis of cyclohexanone oxime under acidic conditions, but acidic hydrolysis of cyclohexanone oxime is generally studied as an effective deoximation method.

[0003] For a long time, the industrial production of cyclohexanone oxime has been based on hydroxylamine salts. The hydrolysis of cyclohexanone oxime to produce hydroxylamine was considered uneconomical. However, with the advent of TS-1 titanium silicalite and the continuous advancement of its synthesis technology, the one-step synthesis of cyclohexanone oxime from cyclohexanone catalyzed by TS-1 titanium silicalite, using ammonia and hydrogen peroxide as the ammonia oxidant, has gradually matured and been industrialized, breaking the monolithic production of cyclohexanone oxime by the traditional hydroxylamine method. Exploring the hydrolysis reaction of cyclohexanone oxime as a potential route for the synthesis of hydroxylamine has become both rational and feasible. Summary of the Invention

[0004] The present invention aims to provide a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. The solid acid-supported porous silica catalyst of the present invention can efficiently catalyze the hydrolysis of cyclohexanone oxime, has high catalytic efficiency, and produces a high conversion rate and yield of hydroxylamine hydrochloride, with few side reactions and high product purity, thus having broad application prospects.

[0005] The technical solution of the present invention is achieved as follows:

[0006] The invention provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. The method comprises the following steps: uniformly mixing cyclohexanone oxime, water, a catalyst and hydrochloric acid, heating for reaction, extracting the reaction solution three times with toluene, placing the residual aqueous phase in a low-temperature reaction bath, neutralizing the solution to a pH value of 6.0-7.0, filtering under reduced pressure to remove precipitates, washing the filter cake three times with deionized water, rotary evaporating the obtained filtrate to obtain a crude hydroxylamine hydrochloride product, and washing and vacuum drying the crude product to obtain the hydroxylamine hydrochloride.

[0007] As a further improvement of the present invention, the temperature of the heating reaction is 55-65° C. and the time is 0.5-1.5 h.

[0008] As a further improvement of the present invention, the molar ratio of cyclohexanone oxime, water and hydrochloric acid is 1:15-20:2-3.

[0009] As a further improvement of the present invention, the catalyst is sulfonic acid-modified graphene oxide-coated porous silica.

[0010] As a further improvement of the present invention, the preparation method of the catalyst is as follows:

[0011] S1. Preparation of porous silica: alkyl orthosilicate was dissolved in ethanol, ammonia, water and a porogen were added, the reaction was heated with stirring, centrifuged, washed and dried to obtain porous silica;

[0012] S2. Graphene oxide coating: Graphene oxide was added to water, ultrasonically dispersed, porous silica was added, stirred and mixed, and spray-dried to obtain graphene oxide-coated porous silica;

[0013] S3. Preparation of the catalyst: Add graphene oxide-coated porous silica to water, add sodium styrene sulfonate, heat and stir to react, add ascorbic acid, continue stirring to react at a constant temperature, wash after the reaction, collect the product by filtration, and freeze-dry to obtain the catalyst.

[0014] As a further improvement of the present invention, the alkyl orthosilicate in step S1 is methyl orthosilicate or ethyl orthosilicate, the temperature of the heating and stirring reaction is 40-50° C., the time is 8-10 hours, and the porogen is hexadecyltrimethylammonium bromide.

[0015] As a further improvement of the present invention, the mass ratio of the alkyl orthosilicate, ethanol, ammonia water, water and porogen in step S1 is 10-15:80-120:7-10:10-12:1-2.

[0016] As a further improvement of the present invention, the mass ratio of graphene oxide to porous silica in step S2 is 3-5:10.

[0017] As a further improvement of the present invention, in step S3, the mass ratio of the graphene oxide-coated porous silica, sodium styrene sulfonate, and ascorbic acid is 10:2-3:4-6.

[0018] As a further improvement of the present invention, the temperature of the heating and stirring reaction in step S3 is 75-85° C., the time is 10-20 hours, and the time of the constant temperature and stirring reaction is 6-10 hours.

[0019] The present invention has the following beneficial effects:

[0020] The present invention prepares a high-efficiency catalyst, which is a solid acid-supported porous silica catalyst. The catalyst can efficiently catalyze the hydrolysis of cyclohexanone oxime, has high catalytic efficiency, high conversion rate and yield of the prepared hydroxylamine hydrochloride, few side reactions, and high product purity, and has broad application prospects. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Preparation Example 1 Preparation of catalyst

[0023] Here’s how:

[0024] S1. Preparation of porous silica: 10 g of methyl orthosilicate was dissolved in 80 g of ethanol, 7 g of aqueous ammonia, 10 g of water, and 1 g of hexadecyltrimethylammonium bromide were added, heated to 40 ° C, stirred for 8 h, centrifuged, washed, and dried to obtain porous silica;

[0025] S2. Graphene oxide coating: 3 g of graphene oxide was added to water, ultrasonically dispersed at 1000 W for 15 min, 10 g of porous silica was added, stirred and mixed for 15 min, and spray-dried to obtain graphene oxide-coated porous silica;

[0026] S3. Preparation of the catalyst: Add 10 g of graphene oxide-coated porous silica to 100 mL of water, add 2 g of sodium styrene sulfonate, heat to 75°C, stir and react for 10 h, add 4 g of ascorbic acid, continue stirring and react at a constant temperature for 6 h. After the reaction is completed, wash and filter the product, and freeze-dry it to obtain the catalyst.

[0027] Preparation Example 2 Preparation of catalyst

[0028] Here’s how:

[0029] S1. Preparation of porous silica: 15 g of tetraethyl orthosilicate was dissolved in 120 g of ethanol, 10 g of aqueous ammonia, 2 g of water, and 2 g of hexadecyltrimethylammonium bromide were added, heated to 50 ° C, stirred for 10 h, centrifuged, washed, and dried to obtain porous silica;

[0030] S2. Graphene oxide coating: 5 g of graphene oxide was added to water, ultrasonically dispersed at 1000 W for 15 min, 10 g of porous silica was added, stirred and mixed for 15 min, and spray-dried to obtain graphene oxide-coated porous silica;

[0031] S3. Preparation of catalyst: Add 10 g of graphene oxide-coated porous silica to 100 mL of water, add 3 g of sodium styrene sulfonate, heat to 85°C, stir and react for 20 h, add 6 g of ascorbic acid, continue stirring and react at a constant temperature for 10 h. After the reaction is completed, wash and filter the product, and freeze-dry it to obtain the catalyst.

[0032] Preparation Example 3 Preparation of catalyst

[0033] Here’s how:

[0034] S1. Preparation of porous silica: 12 g of tetraethyl orthosilicate was dissolved in 100 g of ethanol, 8 g of aqueous ammonia, 11 g of water, and 1.5 g of hexadecyltrimethylammonium bromide were added, heated to 45 ° C, stirred for 9 h, centrifuged, washed, and dried to obtain porous silica;

[0035] S2. Graphene oxide coating: 4 g of graphene oxide was added to water, ultrasonically dispersed at 1000 W for 15 min, 10 g of porous silica was added, stirred and mixed for 15 min, and spray-dried to obtain graphene oxide-coated porous silica;

[0036] S3. Preparation of catalyst: Add 10 g of graphene oxide-coated porous silica to 100 mL of water, add 2.5 g of sodium styrene sulfonate, heat to 80°C, stir and react for 15 h, add 5 g of ascorbic acid, continue stirring and react at a constant temperature for 8 h, after the reaction is completed, wash, and collect the product by filtration, and freeze-dry to obtain the catalyst.

[0037] Example 1

[0038] This example provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. 1 mol of cyclohexanone oxime, 15 mol of water, the catalyst prepared in Preparation Example 1, and 2 mol of hydrochloric acid are uniformly mixed, wherein the catalyst is added in an amount of 0.1 wt % based on the total mass of the system. The mixture is heated to 55° C. and stirred for 0.5 h. The reaction solution is extracted three times with toluene. The residual aqueous phase is placed in a low-temperature reaction bath and neutralized to a pH of 6.0. The precipitate is removed by filtration under reduced pressure, and the filter cake is washed three times with deionized water. The resulting filtrate is subjected to rotary evaporation to obtain crude hydroxylamine hydrochloride. The crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0039] Example 2

[0040] This example provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. 1 mol of cyclohexanone oxime, 20 mol of water, the catalyst prepared in Preparation Example 2, and 3 mol of hydrochloric acid are uniformly mixed, wherein the catalyst is added in an amount of 0.1 wt% based on the total mass of the system. The mixture is heated to 65° C. and stirred for 1.5 hours. The reaction solution is extracted three times with toluene. The residual aqueous phase is placed in a low-temperature reaction bath and neutralized to a pH of 7.0. The precipitate is removed by filtration under reduced pressure, and the filter cake is washed three times with deionized water. The resulting filtrate is subjected to rotary evaporation to obtain crude hydroxylamine hydrochloride. The crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0041] Example 3

[0042] This example provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. 1 mol of cyclohexanone oxime, 17 mol of water, the catalyst prepared in Preparation Example 3, and 2.5 mol of hydrochloric acid are uniformly mixed, wherein the catalyst is added in an amount of 0.1 wt % based on the total mass of the system. The mixture is heated to 60° C. and stirred for 1 hour. The reaction solution is extracted three times with toluene. The residual aqueous phase is placed in a low-temperature reaction bath and neutralized to a pH of 6.5. The precipitate is removed by filtration under reduced pressure, and the filter cake is washed three times with deionized water. The resulting filtrate is subjected to rotary evaporation to obtain crude hydroxylamine hydrochloride. The crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0043] Comparative Example 1

[0044] Compared with Example 3, the difference is that no catalyst is added.

[0045] This embodiment provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime. 1 mol of cyclohexanone oxime, 17 mol of water, and 2.5 mol of hydrochloric acid are uniformly mixed, heated to 60° C., stirred and reacted for 1 hour, and the reaction liquid is extracted three times with toluene. The residual aqueous phase is placed in a low-temperature reaction bath and neutralized to a pH of 6.5. The precipitate is removed by filtration under reduced pressure, and the filter cake is washed three times with deionized water. The resulting filtrate is subjected to rotary evaporation to obtain crude hydroxylamine hydrochloride. The crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0046] Test Example 1

[0047] The reactions in Examples 1-3 of the present invention and Comparative Example 1 were evaluated, and the results are shown in Table 1.

[0048] Table 1

[0049] Group Cyclohexanone oxime conversion rate (%) Yield of hydroxylamine hydrochloride (%) Example 1 95.6 66.6 Example 2 96.2 66.9 Example 3 96.9 67.2 Comparative Example 1 88.5 48.9

[0050] As can be seen from the above table, the methods in Examples 1-3 of the present invention significantly improved the conversion rate of cyclohexanone oxime and the total yield of hydroxylamine hydrochloride.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing hydroxylamine hydrochloride from cyclohexanone oxime, characterized in that: Cyclohexanone oxime, water, a catalyst and hydrochloric acid are uniformly mixed and heated for reaction. The reaction solution is extracted with toluene three times. The residual aqueous phase is placed in a low-temperature reaction bath and neutralized to a pH value of 6.0-7.

0. The precipitate is removed by filtration under reduced pressure. The filter cake is washed three times with deionized water. The obtained filtrate is subjected to rotary evaporation to obtain a crude hydroxylamine hydrochloride product. The crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride. The catalyst is sulfonic acid-modified graphene oxide-coated porous silica, and the preparation method is as follows: S1. Preparation of porous silica: alkyl orthosilicate was dissolved in ethanol, ammonia, water, and a porogen were added, the reaction was heated and stirred, centrifuged, washed, and dried to obtain porous silica; S2. Graphene oxide coating: Graphene oxide was added to water, ultrasonically dispersed, porous silica was added, stirred and mixed, and spray-dried to obtain graphene oxide-coated porous silica; S3. Catalyst Preparation: Graphene oxide-coated porous silica was added to water, followed by sodium styrene sulfonate. The mixture was heated and stirred to react. Ascorbic acid was added and the reaction was continued with stirring at a constant temperature. After the reaction was completed, the product was washed, filtered, and freeze-dried to obtain a catalyst.

2. The method according to claim 1, characterized in that The heating reaction temperature is 55-65° C. and the time is 0.5-1.5 h.

3. The method according to claim 1, characterized in that The molar ratio of cyclohexanone oxime, water and hydrochloric acid is 1:15-20:2-3.

4. The method according to claim 1, wherein In step S1, the alkyl orthosilicate is methyl orthosilicate or ethyl orthosilicate, the temperature of the heating and stirring reaction is 40-50° C., the time is 8-10 hours, and the porogen is hexadecyltrimethylammonium bromide.

5. The method according to claim 1, wherein In step S1, the mass ratio of the alkyl orthosilicate, ethanol, ammonia water, water and porogen is 10-15:80-120:7-10:10-12:1-2.

6. The method according to claim 1, characterized in that The mass ratio of graphene oxide to porous silicon dioxide in step S2 is 3-5:

10.

7. The method according to claim 1, characterized in that In step S3, the mass ratio of the graphene oxide-coated porous silica, sodium styrene sulfonate, and ascorbic acid is 10:2-3:4-6.

8. The method according to claim 1, characterized in that The temperature of the heating and stirring reaction in step S3 is 75-85° C., the time is 10-20 hours, and the time of the constant temperature stirring reaction is 6-10 hours.