Method for preparing hydroxylamine hydrochloride from cyclohexanone oxime

Abstract

The invention provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime, and belongs to the technical field of organic chemistry. The preparation method comprises the following steps: uniformly mixing cyclohexanone-oxime, water, a catalyst and hydrochloric acid, heating to react, extracting reaction liquid for three times by using methylbenzene, putting a raffinate water phase into a low-temperature reaction bath, neutralizing until the pH value is 6.0-7.0, filtering under reduced pressure to remove precipitate, washing a filter cake for three times by using deionized water, carrying out rotary evaporation on the obtained filtrate to obtain a hydroxylamine hydrochloride crude product, and washing and vacuum drying the crude product to obtain hydroxylamine hydrochloride. The efficient catalyst prepared by the invention is a solid acid supported porous silicon dioxide catalyst, can efficiently catalyze cyclohexanone-oxime hydrolysis, has high catalytic efficiency, and has the advantages of high conversion rate and yield of the prepared hydroxylamine hydrochloride, few side reactions, high product purity and wide application prospect.

Description

Technical Field

[0001] The 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 industrial synthesis methods of hydroxylamine salts mainly include Raschig method, NO catalytic reduction method, nitrate ion reduction method and nitroalkane hydrolysis method, while cyclohexanone oxime can also be used as a raw material to generate hydroxylamine products by hydrolysis under acidic conditions. However, the acidic hydrolysis reaction of cyclohexanone oxime is usually studied as one of the effective methods for deoximation.

[0003] For a long time, the industrial production of cyclohexanone oxime has been carried out using hydroxylamine salts as raw materials, and the process of preparing hydroxylamine by hydrolysis of cyclohexanone oxime was considered uneconomical. However, with the advent of TS-1 titanium silicalite and the continuous advancement of its synthesis technology, the process of synthesizing cyclohexanone oxime in one step by catalyzing cyclohexanone with ammonia water and hydrogen peroxide as ammonia oxidants has gradually matured and has been industrialized, thus breaking the single situation of producing cyclohexanone oxime by the traditional hydroxylamine method. It is reasonable and feasible to explore the hydrolysis reaction of cyclohexanone oxime and use it as a potential route for the synthesis of hydroxylamine. Summary of the invention

[0004] The purpose of the present invention is 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, has high conversion rate and yield of the prepared hydroxylamine hydrochloride, has few side reactions, has high product purity, and has broad application prospects.

[0005] The technical solution of the present invention is achieved in this way:

[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 liquid with toluene for three times, placing the residual water 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 for 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: dissolving alkyl orthosilicate in ethanol, adding ammonia, water and a porogen, heating and stirring to react, centrifuging, washing and drying to obtain porous silica;

[0012] S2. Graphene oxide coating: adding graphene oxide to water, uniformly dispersing by ultrasonication, adding porous silica, stirring and mixing, spray drying, and obtaining graphene oxide-coated porous silica;

[0013] S3. Preparation of catalyst: Add graphene oxide-coated porous silica into water, add sodium styrene sulfonate, heat and stir to react, add ascorbic acid, continue to stir and react at a constant temperature, wash after the reaction, collect the product by suction, and freeze-dry to obtain a 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 continuous stirring reaction is 6-10 hours.

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

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

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 ammonia water, 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 catalyst: Add 10g of graphene oxide-coated porous silica to 100mL of water, add 2g of sodium styrene sulfonate, heat to 75°C, stir and react for 10h, add 4g of ascorbic acid, continue stirring and reacting at a constant temperature for 6h, after the reaction is completed, wash, collect the product by suction, and freeze-dry 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 ammonia water, 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 10g of graphene oxide-coated porous silica to 100mL of water, add 3g of sodium styrene sulfonate, heat to 85°C, stir and react for 20h, add 6g of ascorbic acid, continue stirring and reacting at a constant temperature for 10h, after the reaction is completed, wash, collect the product by filtration, and freeze-dry 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 ammonia water, 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 10g of graphene oxide-coated porous silica to 100mL of water, add 2.5g of sodium styrene sulfonate, heat to 80°C, stir and react for 15h, add 5g of ascorbic acid, continue stirring and reacting at a constant temperature for 8h, after the reaction is completed, wash, and collect the product by suction, and freeze-dry to obtain the catalyst.

[0037] Example 1

[0038] The present embodiment 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 amount of the catalyst added is 0.1 wt% of the total mass of the system, the mixture is heated to 55° C., stirred for reaction for 0.5 h, the reaction solution is extracted three times with toluene, the residual water phase is placed in a low-temperature reaction bath, neutralized to a pH value of 6.0, filtered under reduced pressure to remove precipitates, 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, and the crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0039] Example 2

[0040] The present embodiment 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 amount of the catalyst added is 0.1 wt% of the total mass of the system, the mixture is heated to 65° C., stirred for reaction for 1.5 h, the reaction solution is extracted three times with toluene, the residual water phase is placed in a low-temperature reaction bath, neutralized to a pH value of 7.0, filtered under reduced pressure to remove precipitates, 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, and the crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0041] Example 3

[0042] The present embodiment provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime, wherein 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 amount of the catalyst added is 0.1 wt% of the total mass of the system, the mixture is heated to 60° C., stirred for reaction for 1 hour, the reaction solution is extracted three times with toluene, the residual water phase is placed in a low-temperature reaction bath, neutralized to a pH value of 6.5, filtered under reduced pressure to remove precipitates, 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, and the crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

[0043] Comparative Example 1

[0044] The difference compared with Example 3 is that no catalyst is added.

[0045] The present embodiment provides a method for preparing hydroxylamine hydrochloride from cyclohexanone oxime, comprising uniformly mixing 1 mol of cyclohexanone oxime, 17 mol of water and 2.5 mol of hydrochloric acid, heating to 60° C., stirring and reacting for 1 hour, extracting the reaction solution three times with toluene, placing the residual water phase in a low-temperature reaction bath, neutralizing to a pH value of 6.5, 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 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 (%) Hydroxylamine hydrochloride yield (%) 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] It can be seen from the above table that the methods in Examples 1-3 of the present invention significantly improve 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 principle of the present invention should be included in the protection scope 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 mixed evenly, heated for reaction, the reaction liquid is extracted with toluene three times, the residual water phase is placed in a low-temperature reaction bath, neutralized to a pH value of 6.0-7.0, and then filtered under reduced pressure to remove the precipitate, the filter cake is washed three times with deionized water, and the obtained filtrate is subjected to rotary evaporation to obtain a crude hydroxylamine hydrochloride product, and the crude product is washed and vacuum dried to obtain hydroxylamine hydrochloride.

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

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, characterized in that: The catalyst is sulfonic acid modified graphene oxide coated porous silica.

5. The method according to claim 4, characterized in that The preparation method of the catalyst is as follows: S1. Preparation of porous silica: dissolving alkyl orthosilicate in ethanol, adding ammonia, water and a porogen, heating and stirring to react, centrifuging, washing and drying to obtain porous silica; S2. Graphene oxide coating: adding graphene oxide to water, uniformly dispersing by ultrasonication, adding porous silica, stirring and mixing, spray drying, and obtaining graphene oxide-coated porous silica; S3. Preparation of catalyst: Add graphene oxide-coated porous silica into water, add sodium styrene sulfonate, heat and stir to react, add ascorbic acid, continue to stir and react at a constant temperature, wash after the reaction, collect the product by suction, and freeze-dry to obtain a catalyst.

6. The method according to claim 5, characterized in that 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.

7. The method according to claim 5, characterized in that 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.

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

10.

9. The method according to claim 5, 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.

10. The method according to claim 5, 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.