ES2895202A2 - Dl-p-hydroxybenzene hydantoin and urea sulfate/ammonium sulfate production process thereof - Google Patents

Abstract

Disclosed are DL-p-hydroxybenzene hydantoin and a urea sulfate/ammonium sulfate production process thereof. The production process comprises the following steps: step 1, adding phenol, urea and sulfuric acid into a reaction kettle according to a molar ratio, heating the mixture slowly, controlling the reaction temperature at 70-95ºC, and keeping the temperature for 30 min; step 2, dropwise adding glyoxylic acid into the reaction liquid in the step 1, and the adding time being controlled to be 2-8 h; and step 3, after the dropwise addition reaction is finished, controlling the temperature in the reaction kettle to be no lower than 85ºC, and keeping the temperature for 2-5 h before discharging. The present invention has the following beneficial effects: compared with the process for synthesizing the DL-p-hydroxybenzene hydantoin product by using a hydrochloric acid method, the process in the present invention achieves that product quality and yield are both improved, and solves the problems that in the process for synthesizing the DL-p-hydroxybenzene hydantoin product by using the hydrochloric acid method, a large amount of HCL gas is released at production site, and waste hydrochloric acid and other organic matters have negative impact on the production environment and production equipment.

Description

DL-hydroxyphenyl hydantoin and the subsequent production process of urea sulfate/ammonium sulfate

technical area

The present invention relates to DL-hydroxyphenyl hydantoin, specifically a DL-hydroxyphenyl hydantoin and the consequent process for the production of urea sulfate/ammonium sulfate.

State of the art

In China at present, DL-hydroxyphenyl hydantoin is produced by hydrochloric acid process, which has the following defects: 1. During the production of DL-hydroxyphenyl hydantoin, a large amount of harmful HCl gas is generated, which impacts the the production environment and on the equipment and which demands an absorption tower to purify and handle; 2. During wastewater treatment, a large amount of hazardous solid waste is produced, which requires treatment by a specialized company and is therefore expensive; 3. All production equipment is susceptible to corrosion and its maintenance involves high expenses; 4. The content of residual products in DL-hydroxyphenyl hydantoin products is comparatively high. In short, the shortcomings with the hydrochloric acid process are that there is a large amount of hazardous solid waste production, wastewater treatment is difficult and expensive, especially the huge solid waste produced during the production process, which has become in the biggest obstacle that affects the regular production of a company.

Summary of the invention

The object of the present invention is to address the shortcomings that arise when producing DL-hydroxyphenyl hydantoin with the hydrochloric acid process, namely the difficult and costly treatment of three residues and the production of several solid residues. In the present invention, based on the glyoxylic acid raw materials, phenol, urea, and sulfuric acid, with a certain molar ratio, the DL-hydroxyphenyl hydantoin product is obtained by condensation, suction filtration, centrifugation, washing and drying. At a high temperature, by means of the condensation and dissolution of the production mother liquor, eliminating the organic products by means of pressurization and distillation, neutralization with ammoniacal water, reaction, cooling, crystallization and separation, urea sulfate and ammonium sulfate are produced, suitable for the production of compound fertilizers for domestic use.

To carry out the aforementioned objective, the present invention provides the following technical design: A process for producing DL-hydroxyphenyl hydantoin and the consequent urea sulfate and ammonium sulfate, comprising the following steps:

Step 1: Put phenol, urea and sulfuric acid into a reaction kettle according to a predetermined molar ratio, heat gently, keep the reaction kettle temperature at 70-95°C, and hold for 30 minutes;

Step 2: Add the glyoxylic acid dropwise into the reaction solution of step 1, and control the dripping time to be between 2-8 hours;

Step 3: After the dripping reaction is finished, check that the temperature of the reaction kettle is not lower than 85°C, keep it like that for 2-5 hours, and discharge the materials inside it;

Step 4: Discharge the materials inside the reaction kettle into a filter soon, carry out suction filtration until no water droplets are visible to the naked eye, and transfer the materials to a prepared centrifuge while still hot;

Step 5: Fill the centrifuge with hot water at a temperature not lower than 85°C, so that it covers the surface of the materials, centrifuge and wash three times, and compact the materials to dry until the water content does not exceed the 0.5%, and package as a product;

Step 6: Collect the filtered mother liquor and wash water, use part of the mother liquor in step 1, and keep the residual mother liquor as mother liquor for condensation to obtain urea sulfate and ammonium sulfate;

Step 7: Put the recovered mother liquor into a condensing boiler, control the temperature of the condensing boiler not to exceed 115°C, distil for as long as desired under actual conditions, and collect the distilled liquid;

Step 8: Add ammonium water to the mother liquor in a regulating vessel to adjust the PH value to 1-5.5, put the mother liquor into a condensing boiler for condensation, after condensation, inject the hot liquid condensed in ammonium sulfate crystallization kettle to be cooled and crystallized, separating crude ammonium sulfate by centrifugation; and send the separated liquid to the condensation system;

Step 9: Put the cold liquid from the condensing kettle into the crystallizing kettle to separate the residual product of urea sulfate/ammonium sulfate with a centrifuge, and put the separated liquid into the condensing kettle for condensation;

Step 10: Heat the condensing boiler to 100°C, a lot of water is distilled, separate some of the water to be condensed through a distillation tower, and send the condensed water to a sewage treatment system, discharging some steam of water.

Preferably, the molar ratio of phenol, urea and acid sulfate in step 1 is (0.5 1.0): (0.9-1.3): (0.9-1.3).

In a preferred embodiment, the catalyst used in step 1 is acid sulfate with a concentration of 36-75%.

In a preferred embodiment, in step 2, the amount of glyoxylic acid added per dripping, with a concentration of 40-75%, is 1.0-1.4 mol.

In a preferred embodiment, from step 6 to step 9, acid sulfate is used as a catalyst and ammonium water is added in the condensed mother liquor to neutralize the mother liquor.

In a preferred embodiment, in step 8, the temperature in the condensing boiler does not exceed 115°C, and it is cooled down to a normal temperature after the reaction.

In a preferred embodiment, in step 9, the separated liquid is sent back to the condensing boiler for condensing and treatment, and is discharged when it is treated to suitability.

In a preferred embodiment, in step 6, the urea sulfate content is 8-12% and the ammonium sulfate content is 85-95%.

The beneficial effects of the present invention over the existing art are that: Compared with the production process of DL-hydroxyphenyl hydantoin with hydrochloric acid, the production process according to the present invention improves the product quality and the coefficient of performance, and addresses problems that arise during the production of DL-hydroxyphenyl hydantoin with hydrochloric acid, namely, the emission of a large amount of Hcl gas, and the impact on the production environment and equipment that is produced due to waste of hydrochloric acid. It effectively overcomes shortcomings such as large amount of solid waste and difficult and expensive wastewater treatment by producing DL-hydroxyphenyl hydantoin with hydrochloric acid, and makes it possible to reduce solid waste production by 90%. ; Meanwhile, the residual products of urea sulfate and ammonium sulfate obtained in the present invention can be used in the production of fertilizer compounds, which not only reduces the treatment cost of wastewater but also increases the economic benefit; and through micro electrolysis, absorption by resin filtration, flocculation, decolorization and filtration with reverse osmosis membranes, the wastewater produced during production can be made suitable for discharge.

Brief description of the drawings

Figure 1 is a flow chart of the production process of DL-hydroxyphenyl hydantoin according to the present invention;

Figure 2 is a chemical formula of the main reaction of DL-hydroxyphenyl hydantoin according to the present invention.

Figure 3 is a chemical formula of the side reaction of DL-hydroxyphenyl hydantoin according to the present invention.

achievements

In the following paragraphs, a clear and complete description of the technical design with the embodiments of the present invention is provided together with the attached drawings; the embodiments described in this document are only some examples of the present invention, they are not all. Based on the embodiments provided in the present invention, any other embodiment that a person of ordinary skill in the art achieves without involving creative effort falls within the scope of protection of the present invention.

Please see figure 1 to figure 3. The present invention provides a technical plan: A DL-hydroxyphenyl hydantoin and the consequent production process of urea sulfate/ammonium sulfate:

Step 1: Put phenol, urea and sulfuric acid into a reaction kettle according to a certain molar ratio, heating the reaction kettle gently, controlling the reaction temperature to be between 70-95°C, keeping for 30 minutes;

Step 2: Drop the glyxylic acid onto the reaction liquid from step 1 and check that the dripping time is between 2 hours and 8 hours;

Step 3: After the dripping reaction is finished, check that the temperature of the reaction kettle is not lower than 85°C, keep it for 2-5 hours and discharge;

Step 4: Discharge the materials inside the reaction kettle into a filter soon, carry out suction filtration until no water droplets are visible to the naked eye, and transfer the materials to a prepared centrifuge while still hot;

Step 5: Fill the centrifuge with hot water at a temperature not lower than 85°C, so that it covers the surface of the materials, spin and wash three times, compact the materials, dry until the water content does not exceed 0, 5%, and pack;

Step 6: Collect the filtered mother liquor and wash water all together, use part in step 1, and condense the rest of the mother liquor to obtain urea sulfate and ammonium sulfate;

Step 7: Put the recovered mother liquor into a condensing kettle, control the temperature of the condensing kettle not to exceed 115°C, control the distillation time as desired under actual conditions, and collect the distilled liquid;

Step 8: Add ammonium water to the mother liquor in a regulating vessel to adjust the PH value to 1-5.5, put the mother liquor into a condensing boiler for condensation, after condensation, cool and crystallize by injection of the condensed hot liquid into an ammonium sulfate crystallization boiler, separating the crude ammonium sulfate by centrifugation; and put back the separated liquid in the condensing system;

Step 9: Put the cooled liquid from the condensing kettle into a crystallization kettle to separate the residual product of urea sulfate/ammonium sulfate with a centrifuge, and put the separated liquid into the condensing kettle for condensation;

Step 10: Heat the condensing boiler to 100°C, a large amount of water is distilled, converted into condensed water by the distillation tower, and sent to a sewage treatment system for treatment, and discharge a little of water vapor.

In the above, the molar ratio of phenol, urea and sulfuric acid is (0.5-1.0): (0.9-1.3): (0.9-1.3).

In the above, the catalyst in step 1 is 36-75% sulfuric acid.

Also, in step 2, the amount of gluoxylic acid at a concentration of 40-75% added dropwise is 1.0-1.4 mol.

Also, in steps 6-9, after using sulfuric acid as a catalyst, ammonium water is added to the condensed liquid for neutralization.

Also, in step 8, the temperature of the condensing kettle is not higher than 115°C, and it is cooled down to a normal temperature after the reaction.

Also, in step 9, the separated liquid is sent back to the condensing boiler for condensation and treatment, and is discharged when the treatment is finished.

Furthermore, in step 6, the content of urea sulfate is 8-12% and that of ammonium sulfate is 85-95%.

In a 250 mL four-hole boiling flask with a mechanical mixer, reflux condensing tube, temperature indicator, and dropping funnel, place 37 g urea, 20 g phenol, 40 mL 75% sulfuric acid. While mixing, check that the reaction temperature is 80°C, slowly add a well-weighed solution of 30g of glyoxylic acid at 40% dropwise, while controlling the dripping time, which should be 4 hours with a reaction temperature not lower than 85°C; After dropwise reaction, maintain the temperature, mix for 30 minutes, and cool the reaction liquid to room temperature to precipitate white crystal; filter with suction using a Buchner funnel, wash the filter cake three times with 50 ml of hot water at 85°C, filter by suction until no free water remains on the surface of the filter cake, dry the filter cake by placing it in a drying apparatus until the water content is not more than 0.5%, to obtain 25g of DL-hydrophenyl hydantoin, with a purity greater than 95% and a mass yield coefficient of 85% (counted by phenol) .

Realization 2

In a 1000ml beaker fitted with a mechanical mixer, a temperature indicator and a dropping funnel, with 200ml of reaction liquid, add 150g of urea, 73g of phenol, 125ml of 36% sulfuric acid, while mixing, check that the reaction temperature is 85°C, slowly add 110g, duly weighed, of glyoxylic acid solution at 36% dropwise, check that the dripping time is 4 hours and that the reaction temperature is not lower than 85°C, after dropwise reaction, keep the temperature, mix for 30 minutes, cool the reaction liquid to room temperature to precipitate white crystal. Filter with suction using a Buchner funnel, wash the filter cake three times with 150 ml of hot water at 85°C, filter by suction until no free water remains on the surface of the filter cake, dry the filter cake by placing it in a drying apparatus until the water content is not more than 0.5%, to obtain 92g of DL-hydrophenyl hydantoin, with a purity greater than 98.5% and a mass yield coefficient of 85% (counted by phenol).

Realization 3

Step 1: In an enameled reaction kettle, mix 500L of the reaction mother liquor, add 250kg of urea, 170kg of phenol, 180L of 60% concentration sulfuric acid, control the reaction temperature to 90°C gently , keep the temperature for 30 minutes;

Step 2: After the temperature maintenance time, add 255kg, duly weighed, of glyoxylic acid at 50% dropwise into the reaction kettle, check that the reaction temperature in the reaction kettle is not higher than 90°C ; dripping time should not be less than 4 hours;

Step 3: After the dripping reaction is finished, check the reaction temperature is not lower than 85°C, keep the temperature for 30 minutes; cool to 85°C and prepare for discharge;

Step 4: Discharge the materials from the reaction kettle into a filter soon, suction filter until no water droplets visible to the naked eye remain on the surface of the materials, transfer the material to a prepared centrifuge while the materials are still hot ;

Step 5: Fill the centrifuge with hot water at a temperature not lower than 85°C, so that it covers the surface of the materials, spin and wash three times, compact the materials, dry until the water content does not exceed 0, 5%, and packaging materials;

Step 6: Collect the filtered mother liquor and wash water all together, use part in step 1, and condense the rest of the mother liquor to obtain the urea sulfate and ammonium sulfate products;

Step 7: Put the recovered mother liquor into a condensing boiler, control the temperature of the condensing boiler not to exceed 115°C, distil for 4 hours, and collect the distilled liquids;

Step 8: Add ammonium water to the mother liquor in a regulating vessel to adjust the PH value to 1-5.5, put the mother liquor into a condensing boiler for condensation, after condensation, cool and crystallize by injection of the condensed hot liquid into an ammonium sulfate crystallization boiler, centrifugation and separation of crude ammonium sulfate; put the separated liquid back into the condensing system;

Step 9: Separate the cooled liquid in a crystallization kettle with a centrifuge, to separate the residual products of urea sulfate/ammonium sulfate, send the separated liquid back to the condensation system;

Step 10: Heat the condensing boiler to 100°C with a lot of distilled water, a part is separated to be condensed water by distillation tower and sent to sewage treatment system, and discharge a little water vapor.

Although embodiments of the present invention have been shown and described, to a person of ordinary skill in the art, it will be understood that various changes, modifications, equivalent substitutions, and alterations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is limited only by the claims and equivalents.

Claims (8)

1. A process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate and ammonium sulfate, characterized by including the following steps: Step 1: Put phenol, urea and sulfuric acid into a reaction kettle according to a predetermined molar ratio, heat gently, keep the reaction kettle temperature at 70-95°C, and hold for 30 minutes; Step 2: Add the glyoxylic acid dropwise into the reaction solution of step 1, and control the dripping time to be between 2-8 hours; Step 3: After the dripping reaction is completed, check that the temperature of the reaction kettle is not below 85°C, keep it that way for 2-5 hours, and discharge the materials inside it; Step 4: Discharge the materials inside the reaction kettle into a filter soon, carry out suction filtration until no water droplets are visible to the naked eye, and transfer the materials to a prepared centrifuge while still hot; Step 5: Fill the centrifuge with hot water at a temperature not lower than 85°C, so that it covers the surface of the materials, centrifuge and wash three times, and compact the materials to dry until the water content does not exceed the 0.5%, and package as a product; Step 6: Collect the filtered mother liquor and wash water, use part of the mother liquor in step 1, and keep the residual mother liquor as mother liquor for condensation to obtain urea sulfate and ammonium sulfate; Step 7: Introduce the recovered mother liquor in a condensing boiler, check the temperature of the condensing boiler not to be higher than 115°C, distill for a time as desired under actual conditions, and collect the distilled liquid; Step 8: Add ammonium water to the mother liquor in a regulating vessel to adjust the PH value to 1-5.5, put the mother liquor into a condensing boiler for condensation, after condensation, inject the hot liquid condensed in ammonium sulfate crystallization kettle to be cooled and crystallized, separating crude ammonium sulfate by centrifugation; and send the separated liquid to the condensation system; Step 9: Heat the condensing boiler to 100°C, a lot of water is distilled, separate some of the water to be condensed through a distillation tower, and send the condensed water to a sewage treatment system, discharging some steam of water. 2. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 1, wherein the molar ratio of phenol, urea and acid sulfate in step 1 is (0.5-1, 0): (0.9-1.3): (0.9-1.3). 3. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 2, wherein the catalyst used in step 1 is acid sulfate with a concentration of 36-75%. 4. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 3, wherein, in step 2, the amount of glyoxylic acid at a concentration of 40-75% that is added by drip, it is 1.0-1.4 mol. 5. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 4, wherein, in step 6 to Step 9, acid sulfate is used as a catalyst, and ammonium water is added to the condensed mother liquor to neutralize the mother liquor. 6. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate and ammonium sulfate according to claim 1, wherein, in step 8, the temperature in the condensing boiler is not higher than 115 ° C, and it is cooled to a normal temperature after the reaction. 7. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 1, wherein, in step 9, the separated liquid is sent back to the condensation boiler for its condensation and treatment, and is discharged when it is treated to make it fit. 8. The process for the production of DL-hydroxyphenyl hydantoin and the consequent urea sulfate/ammonium sulfate according to claim 1, wherein, in step 6, the urea sulfate content is 8-12% and the sulfate content ammonium is 85-95%.