A method for post-treatment of a sucrose esterification reaction solution

Abstract

The application discloses a kind of sucrose esterification reaction liquid post-processing methods, belong to chemical industry technical field, the sucrose esterification reaction liquid post-processing method of the present application includes: adding ester substance to the sucrose esterification reaction liquid obtained in the production process of sucralose, then water and acetic acid are removed by vacuum supergravity rectification, and sucrose ester-DMF solution is obtained;The ester substance is selected from the organic acid ester with boiling point lower than 180 DEG C.The process flow of the application is simple, environment-friendly, and the loss rate of product sucrose ester is low, which is suitable for wide industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and particularly relates to a post-processing method for sucrose esterification reaction liquid. Background Art

[0002] Sucralose is the only high-calorie sweetener on the market that is synthesized from sucrose. It has good stability, high safety, and pure sweetness, making it one of the most ideal sweeteners.

[0003] Existing sucralose synthesis processes primarily utilize a single-group protection method, encompassing a three-step reaction process of esterification, chlorination, and alcoholysis. The reaction liquid obtained from sucrose esterification cannot be directly used in the subsequent chlorination reaction due to the presence of impurities such as water and acetic acid. Furthermore, due to the azeotropic effect, water and acetic acid are difficult to separate from the solvent DMF. Consequently, direct distillation is often employed in the industry, where DMF and impurities such as water and acetic acid are evaporated to dryness, resulting in a crude ester with a high viscosity. Fresh DMF is then added for the chlorination reaction. The resulting acidic DMF, containing water and acetic acid, must undergo a series of treatment steps before it can be reused. This process is complex and energy-intensive, and the distillation process also results in loss of the sucrose ester.

[0004] Patents CN108358807 and CN 111574394 mention the use of sodium hydroxide to neutralize acidic DMF, which is cumbersome and costly. In addition, the strong base will cause decomposition and loss of DMF, generating a large amount of solid waste and waste gas that is difficult to handle.

[0005] In view of the shortcomings of the above-mentioned process, it is urgent to develop a new post-treatment method for sucrose esterification reaction liquid to overcome the problems of the existing process such as lengthy and complicated process, high energy consumption, and large product loss. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art post-treatment process for sucrose esterification reaction liquid, which is lengthy and cumbersome, has high energy consumption, and causes large product losses. Thus, a post-treatment method for sucrose esterification reaction liquid is provided. The present invention has a simple process flow, is environmentally friendly, and has a low loss rate of the product sucrose ester, making it suitable for a wide range of industrial applications.

[0007] To this end, the present invention provides the following technical solutions.

[0008] The present invention provides a post-treatment method for a sucrose esterification reaction liquid, comprising:

[0009] Adding esters to the sucrose esterification reaction solution obtained in the sucralose production process, and then performing vacuum high gravity distillation to remove water and acetic acid to obtain a sucrose ester-DMF solution;

[0010] The ester substance is selected from organic acid esters with a boiling point lower than 180°C.

[0011] In a possible implementation, the ester substance is selected from organic acid esters with a boiling point of 70-160°C.

[0012] In a possible implementation, the ester substance is selected from one or more of methyl formate, ethyl formate, propyl formate, butyl formate, amyl formate, phenyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isoamyl acetate, methyl cyclopropane formate, ethyl cyclopropane formate, tert-butyl cyclopropane formate, ethyl cyclobutane formate, ethyl benzoyl formate.

[0013] In a possible implementation, the sucrose esterification reaction solution is obtained by reacting sucrose and acetic anhydride in the presence of a Sn-containing catalyst in a DMF solvent, then quenching with water, and removing the Sn-containing catalyst.

[0014] In a possible implementation, cyclohexane is used for extraction to remove the Sn-containing catalyst.

[0015] In a possible implementation, the mass percentage composition of the sucrose esterification reaction solution includes: DMF 80-93%, sucrose ester 4-13%, water 1.5-4%, acetic acid 1.1-1.5%, cyclohexane 0.1-1%, and DMAC (dimethylacetamide) 0.1-1%.

[0016] In a possible implementation, the amount of the ester substance added is 0.5%-5% of the mass of the sucrose esterification reaction solution, preferably 1%-3%.

[0017] In a possible implementation, the reduced-pressure hypergravity rectification satisfies at least one of the following conditions:

[0018] (1) the absolute pressure is 0.5 KPa-60 KPa;

[0019] (2) the rotation speed is 500-2000 rpm;

[0020] (3) the heating temperature of the column head is 35-90°C;

[0021] (4) the reflux ratio is 10:1-0.5:1.

[0022] In a possible implementation, the reduced-pressure hypergravity rectification is completed by a hypergravity rectification machine, and the hypergravity rectification machine is a multi-stage hypergravity rectification machine with a stage number of 1-3.

[0023] In a possible implementation, the internal rotor packing of the hypergravity rectification machine is a monolithic structured packing.

[0024] Optionally, the integral structured packing is selected from any one of foamed silicon carbide corrugated structured packing, foamed nickel structured packing, titanium alloy structured packing, fin guide plate structured packing, and modified plastic structured packing, or a combination of at least two thereof.

[0025] In a possible implementation, the integral structured packing has an inner diameter of 50 to 300 mm, an outer diameter of 200 to 800 mm, and a height of 200 to 1000 mm.

[0026] In the method of the present invention, after the vacuum high gravity distillation is completed, a sucrose ester-DMF solution is extracted from the heavy component, and a mixed solution containing acetic acid, water, cyclohexane, ester substances and a small amount of DMF is extracted from the light component;

[0027] The sucrose ester-DMF solution has a water content of less than 0.1% and an acetic acid content of less than 0.05%, and can be directly used in subsequent chlorination reactions.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The post-treatment method of the sucrose esterification reaction liquid of the present invention comprises: adding an ester substance to the sucrose esterification reaction liquid obtained in the sucralose production process, and then performing vacuum high gravity distillation to remove water and acetic acid to obtain a sucrose ester-DMF solution; the ester substance is selected from organic acid esters having a boiling point below 180°C.

[0030] The present invention uses ultra-gravity distillation technology to purify sucrose esterification reaction liquid containing water and acetic acid impurities, and utilizes the advantages of large gas-liquid two-phase contact area and fast phase interface renewal speed in ultra-gravity environment to promote the separation of light components and solvent DMF; at the same time, by adding ester substances to change the relative volatility of light components, the volatilization of acetic acid is promoted, the separation effect of the azeotropic system is significantly improved, and the loss of solvent DMF is reduced; the improvement in separation efficiency reduces the residence time of sucrose ester products in the high-temperature environment of the tower bottom and reduces the product loss rate. The present invention directly processes the sucrose esterification reaction liquid obtained in the sucralose production process, and the obtained sucrose ester-DMF solution can be directly used in the subsequent chlorination reaction. The method of the present invention solves the problems of lengthy and cumbersome process, high energy consumption, and large product loss in traditional processes, and is suitable for a wide range of industrial applications. DETAILED DESCRIPTION

[0031] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0032] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0033] Main raw material sources of the examples:

[0034] Sucrose esterification reaction liquid: obtained by reacting sucrose and acetic anhydride in DMF solvent under the action of Sn-containing catalyst, quenching with water, and removing the Sn-containing catalyst by cyclohexane extraction;

[0035] Isobutyl formate: 97%, MacLean Biochemical Technology Co., Ltd.;

[0036] Isoamyl formate: 97%, Aladdin Technology Co., Ltd.

[0037] Ethyl acetate: 99%, Aladdin Technology Co., Ltd.

[0038] Ethyl cyclopropanecarboxylate: 98%, Aladdin Technology Co., Ltd.

[0039] Phenyl formate: 98%, MacLean Biochemical Technology Co., Ltd.;

[0040] Ethyl formate: 99%, Aladdin Technology Co., Ltd.

[0041] Unless otherwise specified, the raw materials and reagents in the present invention can be purchased from commercial sources.

[0042] Ultra-gravity distillation machine: 3 stages, rotor diameter 850 mm, distillation chamber height 1500 mm, Zhejiang Xinchuangxing Technology Co., Ltd., 8503P;

[0043] Foamed silicon carbide corrugated structured packing: inner diameter 150mm, outer diameter 850mm, height 200mm, Zhejiang Xinchuangxing Technology Co., Ltd., SUS316L;

[0044] Modified plastic structured packing: inner diameter 150mm, outer diameter 850mm, height 200mm, Zhejiang Xinchuangxing Technology Co., Ltd., SUS316L;

[0045] Fin guide plate structured packing: inner diameter 150mm, outer diameter 850mm, height 200mm, Zhejiang Xinchuangxing Technology Co., Ltd., SUS316L.

[0046] Product composition analysis method:

[0047] Liquid chromatography analysis conditions: Waters liquid chromatograph, Waters XBridge Amide column, ELSD detector, mobile phase acetonitrile / ammonia 65 / 35, column temperature 45°C.

[0048] Gas chromatography analysis conditions: Shimadzu gas chromatograph, HP-5 column, inlet temperature: 140°C; detector temperature: 300°C; heating program: 50°C for 2 min, then increase to 100°C at 10°C / min; increase to 200°C at 5°C / min; increase to 300°C at 20°C / min and hold for 5 min.

[0049] Example 1

[0050] The structured packing used in the high-gravity distillation machine of this embodiment is foamed silicon carbide corrugated structured packing; the mass percentage composition of the sucrose esterification reaction liquid to be post-treated is DMF 91.29%, sucrose ester 5.14%, water 1.98%, acetic acid 1.12%, cyclohexane 0.25%, and DMAC 0.22%.

[0051] This embodiment provides a post-treatment method for a sucrose esterification reaction liquid, comprising:

[0052] Isobutyl formate was added to the sucrose esterification reaction liquid to be post-treated at a rate of 1 wt%. The liquid was then fed into a high-gravity distillation machine at a rate of 200 kg / h for continuous vacuum high-gravity distillation. The distillation process was conducted at an absolute pressure of 53 kPa, a rotation speed of 2000 rpm, a bottom temperature of 75°C, and a reflux ratio of 10:1. The heavy fraction removed from the distillation process consisted of a sucrose ester-DMF solution after dehydration and acid removal, with a production rate of 182.2 kg / h. The light fraction consisted of a mixture containing DMF and other impurities, with a production rate of 17.8 kg / h.

[0053] The sucrose ester-DMF solution obtained after treatment in this example contains 94.34% DMF, 5.45% sucrose ester, 0.05% water, 0.02% acetic acid, and 0.14% heavy component impurities generated during the process; the sucrose ester recovery rate is 97.5%.

[0054] Sucrose ester recovery rate = mass of sucrose ester in sucrose ester-DMF solution / mass of sucrose ester in the sucrose esterification reaction solution to be post-treated * 100%.

[0055] Heavy impurities refer to heavy components with larger molecular weight that are generated when sucrose esters are destroyed in the high temperature environment of the tower bottom.

[0056] The light component comprises a mixture of DMF and other impurities, wherein DMF accounts for 50.06% and the remaining components are water, acetic acid, cyclohexane, DMAC and isobutyl formate.

[0057] Example 2

[0058] The modified plastic structured packing is used in the supergravity rectifier in this embodiment; the mass percentage composition of the sucrose esterification reaction liquid to be post-treated is as follows: DMF 85.74%, sucrose ester 7.66%, water 3.88%, acetic acid 1.46%, cyclohexane 0.72%, and DMAC 0.54%.

[0059] The post-treatment method for the sucrose esterification reaction liquid provided in this embodiment comprises the following steps:

[0060] Furfuryl acetate is added into the sucrose esterification reaction liquid to be treated at a proportion of 2wt%, and the supergravity rectifier is operated continuously under reduced pressure at a flow rate of 200kg / h; the absolute pressure in the rectification process is 17kPa, the rotating speed is 500rpm, the column bottom temperature is 40℃, and the reflux ratio is 7:1. The heavy component collected in the rectification process is the sucrose ester-DMF solution after water and acid removal, and the flow rate is 171.8kg / h; the light component is a mixture containing DMF and other impurities, and the flow rate is 28.2kg / h.

[0061] The sucrose ester-DMF solution obtained after the treatment in this embodiment contains DMF 91.14%, sucrose ester 8.51%, water 0.08%, acetic acid 0.03%, and heavy component impurities generated in the process 0.24%; the sucrose ester recovery rate is 97.2%.

[0062] The light component is a mixture containing DMF and other impurities, wherein the content of DMF is 40.93%, and the rest of the components are water, acetic acid, cyclohexane, DMAC, and furfuryl acetate.

[0063] Embodiment 3

[0064] The fin baffle structured packing is used in the supergravity rectifier in this embodiment; the mass percentage composition of the sucrose esterification reaction liquid to be post-treated is as follows: DMF 83.24%, sucrose ester 11.83%, water 2.75%, acetic acid 1.39%, cyclohexane 0.46%, and DMAC 0.33%.

[0065] The post-treatment method for the sucrose esterification reaction liquid provided in this embodiment comprises the following steps:

[0066] Ethyl acetate is added into the sucrose esterification reaction liquid to be treated at a proportion of 2wt%, and the supergravity rectifier is operated continuously under reduced pressure at a flow rate of 200kg / h; the absolute pressure in the rectification process is 32kPa, the rotating speed is 1000rpm, the column bottom temperature is 55℃, and the reflux ratio is 5:1. The heavy component collected in the rectification process is the sucrose ester-DMF solution after water and acid removal, and the flow rate is 175.1kg / h; the light component is a mixture containing DMF and other impurities, and the flow rate is 24.9kg / h.

[0067] The sucrose ester-DMF solution obtained after treatment in this example contains 86.82% DMF, 12.85% sucrose ester, 0.04% water, 0.02% acetic acid, and 0.27% heavy component impurities generated during the process; the sucrose ester recovery rate is 98.0%.

[0068] The light component comprises a mixture of DMF and other impurities, wherein DMF accounts for 38.66% and the remaining components are water, acetic acid, cyclohexane, DMAC and ethyl acetate.

[0069] Example 4

[0070] The structured packing used in the high-gravity distillation machine of this embodiment is foamed silicon carbide corrugated structured packing; the mass percentage composition of the sucrose esterification reaction liquid to be post-treated is DMF 85.74%, sucrose ester 7.66%, water 3.88%, acetic acid 1.46%, cyclohexane 0.72%, and DMAC 0.54%.

[0071] This embodiment provides a post-treatment method for a sucrose esterification reaction liquid, comprising:

[0072] Ethyl cyclopropanecarboxylate was added to the sucrose esterification reaction liquid at a rate of 1.5 wt%. The liquid was then fed into a high-gravity distillation machine at a rate of 200 kg / h for continuous vacuum high-gravity distillation. The distillation process was carried out at an absolute pressure of 28 kPa, a rotation speed of 1500 rpm, a bottom temperature of 50°C, and a reflux ratio of 3:1. The heavy fraction removed from the distillation process was a sucrose ester-DMF solution after dehydration and acid removal, with a production rate of 170.7 kg / h; the light fraction was a mixture containing DMF and other impurities, with a production rate of 29.3 kg / h.

[0073] The sucrose ester-DMF solution obtained after treatment in this example contains 91.13% DMF, 8.69% sucrose ester, 0.02% water, 0.01% acetic acid, and 0.15% heavy impurities generated during the process; the sucrose ester recovery rate is 98.3%.

[0074] The light component comprises a mixture of DMF and other impurities, wherein DMF accounts for 45.77% and the remaining components are water, acetic acid, cyclohexane, DMAC and ethyl cyclopropanecarboxylate.

[0075] Example 5

[0076] The structured packing used in the high-gravity distillation machine of this embodiment is a modified plastic structured packing; the mass percentage composition of the sucrose esterification reaction liquid to be post-treated is DMF 83.24%, sucrose ester 11.83%, water 2.75%, acetic acid 1.39%, cyclohexane 0.46%, and DMAC 0.33%.

[0077] The embodiment provides a post-treatment method of a sucrose esterification reaction liquid, which comprises the following steps:

[0078] Phenyl formate is added into the sucrose esterification reaction liquid to be treated in a proportion of 2.5 wt%, and is continuously subjected to a reduced-pressure hypergravity rectification operation in a hypergravity rectification machine at a flow rate of 200 kg / h, wherein the absolute pressure in the rectification process is 60 kPa, the rotating speed is 1000 rpm, the column bottom temperature is 90 DEG C, and the reflux ratio is 5:1. The heavy component collected in the rectification process is a sucrose ester-DMF solution after water and acid removal, and the collection flow rate is 173.6 kg / h; and the light component is a mixture containing DMF and other impurities, and the collection flow rate is 26.4 kg / h.

[0079] The sucrose ester-DMF solution obtained after the treatment in the embodiment contains 86.57% of DMF, 12.88% of sucrose ester, 0.09% of water, 0.04% of acetic acid and 0.42% of the heavy component impurities generated in the process; and the sucrose ester recovery rate is 96.9%.

[0080] The light component is a mixture containing DMF and other impurities, wherein the content of DMF is 45.97%, and the rest of the components are water, acetic acid, cyclohexane, DMAC and phenyl formate.

[0081] Embodiment 6

[0082] The hypergravity rectification machine used in the embodiment uses a fin baffle structured packing as the structured packing; and the mass percentage composition of the sucrose esterification reaction liquid to be treated comprises 91.29% of DMF, 5.14% of sucrose ester, 1.98% of water, 1.12% of acetic acid, 0.25% of cyclohexane and 0.22% of DMAC.

[0083] The embodiment provides a post-treatment method of a sucrose esterification reaction liquid, which comprises the following steps:

[0084] Ethyl formate is added into the sucrose esterification reaction liquid to be treated in a proportion of 4.5 wt%, and is continuously subjected to a reduced-pressure hypergravity rectification operation in a hypergravity rectification machine at a flow rate of 200 kg / h, wherein the absolute pressure in the rectification process is 30 kPa, the rotating speed is 1500 rpm, the column bottom temperature is 50 DEG C, and the reflux ratio is 2:1. The heavy component collected in the rectification process is a sucrose ester-DMF solution after water and acid removal, and the collection flow rate is 170.89 kg / h; and the light component is a mixture containing DMF and other impurities, and the collection flow rate is 29.11 kg / h.

[0085] The sucrose ester-DMF solution obtained after the treatment in the embodiment contains 94.12% of DMF, 5.61% of sucrose ester, 0.09% of water, 0.03% of acetic acid and 0.15% of the heavy component impurities generated in the process; and the sucrose ester recovery rate is 97.4%.

[0086] The light component comprises a mixture of DMF and other impurities, wherein DMF accounts for 47.67% and the remaining components are water, acetic acid, cyclohexane, DMAC and ethyl formate.

[0087] Comparative Example 1

[0088] This comparative example is substantially the same as Example 1, except that isobutyl formate is not added in this comparative example.

[0089] The sucrose ester-DMF solution obtained after treatment in this comparative example contains 92.38% DMF, 5.44% sucrose ester, 1.01% water, 0.59% acetic acid, 0.05% DMAC, and 0.53% heavy component impurities generated during the process; the recovery rate of sucrose ester is 91.1%.

[0090] The light component comprises a mixture of DMF and other impurities, wherein DMF accounts for 84.51% and the remaining components are water, acetic acid, cyclohexane and DMAC.

[0091] It can be seen from Examples 1 to 6 that the sucrose ester-DMF solution prepared by the method of the present invention has a water content of <0.1% and an acetic acid content of <0.05%, and can be directly used in the subsequent chlorination reaction.

[0092] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A post-treatment method for a sucrose esterification reaction liquid, characterized in that: include: Adding esters to the sucrose esterification reaction solution obtained in the sucralose production process, and then performing vacuum high gravity distillation to remove water and acetic acid to obtain a sucrose ester-DMF solution; The ester substance is selected from organic acid esters with a boiling point below 180°C; The sucrose esterification reaction solution comprises, by weight percentage, 80-93% DMF, 4-13% sucrose ester, 1.5-4% water, 1.1-1.5% acetic acid, 0.1-1% cyclohexane, and 0.1-1% dimethylacetamide.

2. The post-processing method of sucrose esterification reaction liquid according to claim 1, characterized in that: The ester substance is selected from organic acid esters with a boiling point of 70-160°C.

3. The post-processing method of sucrose esterification reaction liquid according to claim 1, characterized in that: The ester substance is selected from one or more of methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, phenyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isopentyl acetate, methyl cyclopropanecarboxylate, ethyl cyclopropanecarboxylate, tert-butyl cyclopropanecarboxylate, ethyl cyclobutanecarboxylate, and ethyl benzoylformate.

4. The post-treatment method of the sucrose esterification reaction liquid according to any one of claims 1 to 3, characterized in that: The sucrose esterification reaction liquid is obtained by reacting sucrose and acetic anhydride in a DMF solvent under the action of a Sn-containing catalyst, then adding water for quenching, and removing the Sn-containing catalyst.

5. The post-treatment method of the sucrose esterification reaction liquid according to any one of claims 1 to 3, characterized in that: The amount of ester added is 0.5% to 5% of the mass of the sucrose esterification reaction solution.

6. The post-treatment method of the sucrose esterification reaction liquid according to claim 5, characterized in that: The amount of ester added is 1%~3% of the mass of the sucrose esterification reaction solution.

7. The post-processing method according to any one of claims 1 to 3, characterized in that: The vacuum high gravity distillation satisfies at least one of the following conditions: (1) Absolute pressure 0.5KPa~60KPa; (2) The speed is 500~2000rpm; (3) The heating temperature of the tower kettle is 35~90℃; (4) The reflux ratio is 10:1~0.5:

1.

8. The post-treatment method of the sucrose esterification reaction liquid according to any one of claims 1 to 3, characterized in that: The vacuum high gravity distillation is completed by a high gravity distillation machine, and the high gravity distillation machine is a multi-stage high gravity distillation machine with 1 to 3 stages.

9. The post-treatment method of the sucrose esterification reaction liquid according to claim 8, characterized in that: The internal rotor packing of the ultra-gravity distillation machine is an integral structured packing.

10. The post-treatment method of sucrose esterification reaction liquid according to claim 9, characterized in that: The integral structured packing is selected from any one of foamed silicon carbide corrugated structured packing, foamed nickel structured packing, titanium alloy structured packing, fin guide plate structured packing, and modified plastic structured packing, or a combination of at least two thereof.

11. The post-treatment method of sucrose esterification reaction liquid according to claim 9, characterized in that: The inner diameter of the integral structured packing is 50-300 mm, the outer diameter is 200-800 mm, and the height is 200-1000 mm.