A method for synthesizing acetone glycerol acetal containing water in nitrogen-cyclohexane

Abstract

The invention belongs to the technical field of organic synthesis, and provides a kind of synthetic method of the acetone glycerol acetal of nitrogen-cyclohexane with water.The synthetic method of the present invention, acetone, cyclohexane and catalyst are mixed, and reaction feed liquid is obtained;Under the condition of nitrogen being passed through in the reaction feed liquid, glycerol is added, condensation reaction is carried out, and the acetone glycerol acetal is obtained.The present invention adopts nitrogen to carry water in combination with cyclohexane, and nitrogen accelerates the replacement of solvent and water in condensation reaction, and rapidly reduces the replacement time of the moisture produced by condensation reaction;During condensation reaction, moisture is taken out in time, and condensation reaction can be promoted to proceed, so as to improve feedstock conversion, and the generation of reverse reaction in later distillation process can also be effectively reduced, and is conducive to the improvement of product yield.Meanwhile, after condensation reaction terminates, because moisture is fully taken out, cyclohexane and acetone mixture moisture is very low, saves the dehydration energy consumption of reclaiming acetone, and reduces cost.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for synthesizing nitrogen-cyclohexane glycerol acetone acetal with water. Background Art

[0002] Acetone acetal is generally produced by condensing acetone and glycerol under acidic conditions to obtain acetone acetal and by-product water. This reaction is reversible, that is, acetone acetal is easily hydrolyzed in a water environment to produce acetone and glycerol. The reaction formula is shown below:

[0003]

[0004] If the water generated by the condensation reaction is not promptly processed, the forward and reverse reactions will reach a chemical equilibrium after the forward reaction reaches a certain stage, seriously affecting the product yield. To increase the yield of acetone sol-acetal, existing technologies generally use acetone-water reactions or cyclohexane-water reactions. The acetone-water reaction can slightly increase the yield, but the benefits are not significant. Gas phase analysis results from the cyclohexane-water reaction show that the reaction can push the raw material conversion rate to >95%, and the water content in the kettle ultimately remains around 3%, unable to be removed by cyclohexane. However, during distillation, the product yield was found to be far below the detection target. It is believed that the presence of water during post-processing caused the reverse reaction to continue, reducing the product yield.

[0005] Therefore, during the condensation reaction, especially in the later stage of the reaction, a convenient water removal method is urgently needed to control the reverse reaction phenomenon in the later stage of the reaction to increase the yield of acetone glycerol acetal. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a method for synthesizing acetone soln acetal containing water in nitrogen-cyclohexane. In the synthesis method provided by the present invention, the yield of acetone soln acetal is high.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for synthesizing nitrogen-cyclohexane glycerol acetone acetal with water, comprising the following steps:

[0009] mixing acetone, cyclohexane and a catalyst to obtain a reaction liquid;

[0010] Under the condition of introducing nitrogen into the reaction liquid, glycerol is added to carry out a condensation reaction to obtain the glycerol acetone acetal.

[0011] Preferably, the molar ratio of glycerol to acetone is 1:1-5.

[0012] Preferably, the catalyst is an acidic resin catalyst; the mass of the catalyst is 1 to 40% of the mass of the glycerol.

[0013] Preferably, the mass of the cyclohexane is 50-200% of the mass of the acetone.

[0014] Preferably, the glycerol is added dropwise.

[0015] Preferably, the flow rate of the nitrogen is 20-30 mL / min.

[0016] Preferably, the condensation reaction temperature is 50-100° C., and the time is 1-10 h.

[0017] Preferably, after the condensation reaction, the method further comprises: desolventizing the obtained condensation reaction liquid to obtain a desolventizing solvent and a viscous substance; and performing reduced pressure distillation on the viscous substance.

[0018] Preferably, the desolvation temperature is 70-110°C and the time is 1-3 hours;

[0019] The vacuum degree of the reduced pressure distillation is -100.00 kPa, the temperature is 100-130° C., the top temperature is 75-85° C., and the time is 4-8 hours.

[0020] Preferably, the method further comprises: post-processing the desolvation solvent; the post-processing comprises testing the moisture content of the desolvation solvent and testing the content by gas chromatography; and replenishing raw materials according to the test results obtained, and performing recycling.

[0021] The present invention provides a method for synthesizing acetone glycerol acetal containing water by nitrogen-cyclohexane, comprising the following steps: mixing acetone, cyclohexane, and a catalyst to obtain a reaction liquid; adding glycerol while passing nitrogen through the reaction liquid to carry out a condensation reaction to obtain the acetone glycerol acetal. The present invention uses nitrogen in combination with cyclohexane to carry out water. The nitrogen accelerates the replacement of the solvent (a mixture of cyclohexane and acetone) with water in the condensation reaction, rapidly reducing the replacement time of the water generated by the condensation reaction; during the condensation reaction, the water is promptly removed, enabling the condensation reaction to continue, thereby improving the raw material conversion rate. At the same time, after the condensation reaction is completed, the water content of the cyclohexane and acetone mixture is very low because the water is fully removed, saving the dehydration energy consumption for recovering the acetone and reducing costs. In addition, the nitrogen also has a protective effect, increasing the safety of the condensation reaction.

[0022] Furthermore, glycerol is added to the reaction liquid in a dropwise manner, which increases the contact area between glycerol and acetone and reduces the adsorption of water produced by the condensation reaction by glycerol, making it easier to remove the water.

[0023] The method further includes post-processing the desolventizing solvent; the post-processing includes testing the desolventizing solvent for moisture and gas chromatography content; and replenishing raw materials based on the test results for recycling. The post-processing operation eliminates the need for solvent separation, thereby saving time, raw material costs, and energy consumption.

[0024] The data of the examples show that, taking all factors into consideration, the conversion rate of glycerol in the ideal examples is 79-97%, and the molar yield of glycerol acetone acetal is 60.9-90.1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention provides a schematic diagram of the apparatus structure used in the method for synthesizing acetone glycerol acetal containing water in nitrogen-cyclohexane. The apparatus comprises: 1, a four-necked reaction flask; 2, a stirrer; 3, a magnetic heating stirrer; 4, a nitrogen tube; 5, a thermometer; 6, a constant-pressure burette; 7, a glass stopper; 8, a perforated rubber stopper; 9, a first iron stand; 10, a condenser; 11, a water separator; 12, a second iron stand; 13, a first fixing clamp; 14, a second fixing clamp; 15, a polytetrafluoroethylene tube; 16, a collecting flask; and 17, heat transfer oil. DETAILED DESCRIPTION

[0026] The present invention provides a method for synthesizing nitrogen-cyclohexane glycerol acetone acetal with water, comprising the following steps:

[0027] mixing acetone, cyclohexane and a catalyst to obtain a reaction liquid;

[0028] Under the condition of introducing nitrogen into the reaction liquid, glycerol is added to carry out a condensation reaction to obtain the glycerol acetone acetal.

[0029] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0030] The present invention mixes acetone, cyclohexane and a catalyst to obtain a reaction liquid.

[0031] In the present invention, the catalyst is preferably an acidic resin catalyst; the mass of the catalyst is preferably 1-40% of the mass of the glycerol, more preferably 10-35%, and even more preferably 15-25%. In the present invention, the mass of the cyclohexane is preferably 50-200% of the mass of the acetone, more preferably 100-150%.

[0032] After obtaining the reaction liquid, the present invention adds glycerol under the condition of introducing nitrogen into the reaction liquid to carry out a condensation reaction to obtain the glycerol acetone acetal.

[0033] In the present invention, the molar ratio of glycerol to acetone is preferably 1:1-5, more preferably 1:1.5-4, and even more preferably 1:2-3. In the present invention, the flow rate of nitrogen is preferably 20-30 mL / min. In the present invention, the glycerol is preferably added dropwise at a rate of 1-2 g / min.

[0034] In the present invention, the temperature of the condensation reaction is preferably 50 to 100° C., more preferably 60 to 90° C., and even more preferably 70 to 80° C.; and the time is preferably 1 to 10 h.

[0035] After the condensation reaction, the present invention preferably further comprises: desolventizing the obtained condensation reaction liquid to obtain a desolventizing solvent and a viscous material; and subjecting the viscous material to reduced pressure distillation. In the present invention, the desolventizing temperature is preferably 70 to 110°C, and the time is preferably 1 to 3 hours. In the present invention, the vacuum degree of the reduced pressure distillation is preferably -100.00 kPa, the temperature is preferably 100 to 130°C, the top temperature is preferably 75 to 85°C, and the time is preferably 4 to 8 hours.

[0036] The present invention preferably further comprises: post-processing the desolvation solvent; the post-processing comprises testing the moisture content of the desolvation solvent and testing the content by gas chromatography; and replenishing raw materials based on the test results obtained, and performing recycling.

[0037] Figure 1 The schematic diagram of the device structure used in the synthesis method of nitrogen-cyclohexane acetone glycerol provided by the present invention is shown below in conjunction with Figure 1 The synthesis method provided by the present invention is described:

[0038] At room temperature and pressure, acetone, cyclohexane, and a catalyst are placed in a four-necked reaction flask 1 for later use, and the four-necked reaction flask 1 is fixed to a magnetic heating stirrer 3 via a first iron stand 9 and a second fixing clamp 14. A water separator 11 is installed to connect the four-necked reaction flask 1 and a condenser 10, and the condenser 10 is fixed via a second iron stand 12 and a first fixing clamp 13. A perforated rubber stopper 8 is installed and inserted into a thermometer 5. A nitrogen tube 4 is installed. Glycerin is placed in a constant pressure burette 6 and covered with a glass stopper 7 for later use.

[0039] After the preparation work is completed, the magnetic heating stirrer 3 is turned on, and the four-necked reaction flask 1 is heated using the heat-conducting oil 17 and stirred under the action of the stirrer 2; nitrogen is introduced into the nitrogen pipe 4, the condenser 10 is opened to cool the water, and the temperature of the four-necked reaction flask 1 is controlled to reach the temperature of the condensation reaction. The glycerol in the constant pressure burette 6 is started to be added dropwise, and the water generated by the condensation reaction is brought into the water separator 11 through cyclohexane for separation; the separated water enters the collection flask 16 through the tetrafluoroethylene tube 15.

[0040] After the condensation reaction is completed, the material in the four-necked reaction flask 1 is filtered, and the obtained filtrate is sequentially subjected to desolventizing and reduced pressure distillation.

[0041] The synthesis method of nitrogen-cyclohexane acetone solketal provided by the present invention is described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1

[0043] use Figure 1 The synthesis of glycerol acetone acetal is shown in FIG. , and the specific steps are as follows:

[0044] At room temperature and pressure, 234 g of acetone, 300 g of cyclohexane, and 30 g of an acidic resin catalyst are placed in a four-necked reaction flask 1 for later use, and the four-necked reaction flask 1 is fixed to a magnetic heating stirrer 3 via a first iron stand 9 and a second fixing clamp 14. A water separator 11 is installed to connect the four-necked reaction flask 1 and a condenser 10, and the condenser 10 is fixed thereto via a second iron stand 12 and a first fixing clamp 13. A perforated rubber stopper 8 is installed and inserted into a thermometer 5. A nitrogen tube 4 is installed. 92 g of glycerol is placed in a constant pressure burette 6 and capped with a glass stopper 7 for later use.

[0045] After the preparation work is completed, the magnetic heating stirrer 3 is turned on, the four-necked reaction flask 1 is heated using the thermal oil 17, and stirred under the action of the stirrer 2; nitrogen is introduced into the nitrogen tube 4 (the flow rate of nitrogen is 20 mL / min), the condenser 10 is opened to cool the water, the temperature of the four-necked reaction flask 1 is controlled to reach 55°C, and the glycerol in the constant pressure burette 6 is started to be added dropwise (the dropping speed is 2 g / min). The water generated by the condensation reaction is brought into the water separator 11 through cyclohexane for separation; the separated water enters the collection flask 16 through the tetrafluoroethylene tube 15.

[0046] The condensation reaction was carried out for 3 hours, and the substance in the four-necked reaction flask 1 was filtered. The obtained filtrate began to be desolvated at 90° C. and was gradually heated to 110° C. to complete the desolvation, which took 2 hours to obtain a desolvation solvent and a viscous substance, respectively. The viscous substance was a crude acetone glycerol acetal product. The crude acetone glycerol acetal product was determined by gas chromatography, and the result was: after deducting the acetone and water contents from the crude acetone glycerol acetal product, the mass content of the acetone glycerol acetal was 92.25%, the mass content of the isomers was 2.01%, and the mass content of glycerol was 5.57%. The water content of the crude acetone glycerol acetal product was determined by Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.5%.

[0047] The crude acetone acetal product was subjected to reduced pressure distillation at a vacuum degree of -100.00 kPa, a temperature of 110° C., and a top temperature of 80° C. for 5 hours to obtain 113.3 g of a finished acetone acetal product. The finished acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished acetone acetal product had a total content of 99.90% of acetone acetal 97.43% and isomers 2.47%. Based on the raw material glycerol, the total molar yield of acetone acetal and its isomers was 85.7%. The water content of the finished acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.11%.

[0048] The desolventizing solvent is tested for moisture and gas chromatography content, and raw materials are replenished based on the test results and recycled.

[0049] Example 2

[0050] The operating parameters are the same as those in Example 1, except that the amounts of raw materials added are different, specifically: 290 g of acetone, 30 g of acidic resin catalyst, 360 g of cyclohexane, and 92 g of glycerol.

[0051] A crude acetone soln product was obtained by desolvation under normal pressure. The crude acetone soln product was determined by gas chromatography. The results showed that after deducting the acetone and water contents from the crude acetone soln product, the mass content of the acetone soln product was 94.50%, the mass content of the isomers was 2.04%, and the mass content of glycerol was 2.82%. The water content of the crude acetone soln product was determined by Karl Fischer titrator, and the mass content of water was 0.6%.

[0052] The crude acetone acetal product was subjected to reduced pressure distillation to obtain 119.1 g of a finished acetone acetal product. The finished acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished acetone acetal product had a acetone acetal mass content of 97.96% and an isomer mass content of 1.96%, with a total content of 99.92%. Based on the raw material glycerol, the total molar yield of the acetone acetal and its isomers was 90.1%. The water content of the finished acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the water content was 0.09%.

[0053] Example 3

[0054] The operating parameters are the same as those in Example 1, except that the amounts of raw materials added are different, specifically: 92 g of acetone, 30 g of acidic resin catalyst, 150 g of cyclohexane, and 92 g of glycerol.

[0055] A crude acetone soln product was obtained by desolvation under normal pressure. The crude acetone soln product was determined by gas chromatography. The results showed that after deducting the acetone and water contents from the crude acetone soln product, the mass content of the acetone soln product was 76.70%, the mass content of the isomers was 2.25%, and the mass content of glycerol was 20.59%. The water content of the crude acetone soln product was determined by Karl Fischer titrator, and the mass content of water was 1.8%.

[0056] The crude glycerol acetone acetal product was subjected to reduced pressure distillation to obtain 80.5 g of a finished glycerol acetone acetal product. The finished glycerol acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished glycerol acetone acetal product had a mass content of 97.89% of glycerol acetone acetal and a mass content of 2.06% of isomers, with a total content of 99.95%. Based on the raw material glycerol, the total molar yield of glycerol acetone acetal and its isomers was 60.9%. The water content of the finished glycerol acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.09%.

[0057] Example 4

[0058] The operating parameters are the same as those in Example 1, except that the amounts of raw materials added are different, specifically: 174 g of acetone, 30 g of acidic resin catalyst, 160 g of cyclohexane, and 92 g of glycerol.

[0059] A crude acetone soln product was obtained by desolvation under normal pressure. The crude acetone soln product was determined by gas chromatography. The results showed that after deducting the acetone and water contents from the crude acetone soln product, the mass content of the acetone soln product was 87.11%, the mass content of isomers was 2.04%, and the mass content of glycerol was 10.54%. The water content of the crude acetone soln product was determined by Karl Fischer titrator, and the mass content of water was 1.0%.

[0060] The crude glycerol acetone acetal product was subjected to reduced pressure distillation to obtain 94.6 g of a finished glycerol acetone acetal product. The finished glycerol acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished glycerol acetone acetal product had a mass content of 97.89% of glycerol acetone acetal and a mass content of 2.03% of isomers, for a total content of 99.92%. Based on the raw material glycerol, the total molar yield of glycerol acetone acetal and its isomers was 71.6%. The water content of the finished glycerol acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.10%.

[0061] Example 5

[0062] The operating parameters are the same as those in Example 1, except that the amounts of raw materials added are different, specifically: 232 g of acetone, 30 g of acidic resin catalyst, 150 g of cyclohexane, and 92 g of glycerol.

[0063] A crude acetone soln product was obtained by desolvation under normal pressure. The crude acetone soln product was determined by gas chromatography. The results showed that after deducting the acetone and water contents from the crude acetone soln product, the mass content of the acetone soln product was 81.42%, the mass content of the isomers was 2.12%, and the mass content of glycerol was 15.67%. The water content of the crude acetone soln product was determined by Karl Fischer titrator, and the mass content of water was 1.2%.

[0064] The crude glycerol acetone acetal product was subjected to reduced pressure distillation to obtain 85.6 g of a finished glycerol acetone acetal product. The finished glycerol acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished glycerol acetone acetal product had a mass content of 97.97% of glycerol acetone acetal and a mass content of isomers of 1.98%, with a total content of 99.95%. Based on the raw material glycerol, the total molar yield of glycerol acetone acetal and its isomers was 64.8%. The water content of the finished glycerol acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.14%.

[0065] Comparative Example 1

[0066] The operation is different from that of Example 1 in that cyclohexane and nitrogen are not used. The specific materials are: 232 g of acetone, 30 g of acidic resin catalyst, and 92 g of glycerol.

[0067] After desolventizing under normal pressure, stratification occurred in the kettle. The upper layer was a crude acetone glycerol acetal product. The crude acetone glycerol acetal product was determined by gas chromatography, and the result was: after deducting the acetone and water contents from the crude acetone glycerol acetal product, the mass content of the acetone glycerol acetal was 86.45%, the mass content of the isomers was 2.05%, and the mass content of glycerol was 11.21%; the water content in the crude acetone glycerol acetal product was determined by Karl Fischer titrator, and the result was that the mass content of water was 2.2%; the lower layer was a glycerol layer, and the glycerol layer was determined by gas chromatography, and the result was: the mass content of the acetone glycerol acetal was 9.75%, the mass content of the isomers was 1.57%, and the mass content of glycerol was 88.02%; the water content in the glycerol layer was determined by Karl Fischer titrator, and the result was that the mass content of water was 3.41%.

[0068] The crude glycerol acetone acetal product was subjected to reduced pressure distillation to obtain 66.9 g of a finished glycerol acetone acetal product. The finished glycerol acetone acetal product was determined by gas chromatography, and the result showed that after deducting the integral of the water content, the finished glycerol acetone acetal product had a mass content of 98.11% of glycerol acetone acetal and a mass content of isomers of 1.86%, with a total content of 99.97%. Based on the raw material glycerol, the total molar yield of glycerol acetone acetal and its isomers was 50.7%. The water content of the finished glycerol acetone acetal product was determined by a Karl Fischer moisture analyzer, and the result showed that the mass content of water was 0.15%.

[0069] By comparing the above examples, it can be seen that different raw material ratios will also affect the final yield of glycerol acetone acetal; however, if cyclohexane and nitrogen are not used to carry water, the yield of glycerol acetone acetal is lower.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for synthesizing acetone glycerol acetal containing water in nitrogen-cyclohexane, characterized in that: The following steps are involved: mixing acetone, cyclohexane and a catalyst to obtain a reaction liquid; Under the condition of passing nitrogen into the reaction liquid, adding glycerol to carry out a condensation reaction to obtain the glycerol acetone acetal; The molar ratio of glycerol to acetone is 1:5; The catalyst is an acidic resin catalyst; the mass ratio of the catalyst to glycerol is 30:92; The mass ratio of cyclohexane to acetone is 360:290; The glycerol is added dropwise at a rate of 2 g / min. The flow rate of the nitrogen is 20 mL / min; The condensation reaction temperature is 55°C and the time is 3h; After the condensation reaction, the method further comprises: desolventizing the obtained condensation reaction liquid to obtain a desolventizing solvent and a viscous material; The viscous material is subjected to reduced pressure distillation to obtain the glycerol acetone acetal.

2. The synthesis method according to claim 1, wherein The desolvation temperature is 70-110°C and the time is 1-3 hours; The vacuum degree of the reduced pressure distillation is -100.00 kPa, the temperature is 100-130° C., the top temperature is 75-85° C., and the time is 4-8 hours.

3. The synthesis method according to claim 1, wherein Also includes: The desolvation solvent is post-processed; the post-processing includes testing the moisture content of the desolvation solvent and testing the content by gas chromatography; and according to the test results obtained, raw materials are replenished and recycled.

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