Production process method of ethyl chloroformate

Abstract

The invention discloses a production process method of ethyl chloroformate, which specifically comprises the following steps: S1, placing absolute ethyl alcohol in a reactor, cooling, and adding a low-temperature catalyst; s2, introducing phosgene into the reactor while maintaining the introduction temperature; s3, after phosgene is completely introduced, heating to a reaction temperature, keeping the temperature for reaction, and purifying after the reaction is finished to obtain ethyl chloroformate. The prepared low-temperature catalyst is used for reaction, so that the reaction yield and purity are improved, and the method has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a production process for ethyl chloroformate. Background Art

[0002] The molecular formula of ethyl chloroformate is C3H5ClO2, the molecular weight is 108.53, it is a colorless transparent liquid with a pungent odor. It is flammable, toxic and corrosive. The relative density is 1.1403, the melting point is -81°C, and the boiling point is 93°C. It is miscible with ethanol and ether, but can be decomposed by ethanol, soluble in benzene and chloroform, insoluble in water, but can be decomposed by water. Its vapor can strongly irritate the eyes, skin and mucous membranes. Ethyl chloroformate is mainly used in the production of chemical products such as medicines and herbicides, such as cefazolin (Pioneer 5), tetrazolylacetic acid, nicosulfuron, etc. In addition, it is also used as a solvent and amino protective agent.

[0003] Ethyl chloroformate is industrially obtained by esterification of ethanol and phosgene, and then the final product is obtained through purification processes such as impurity removal, dehydration, and fractionation. The preparation process is relatively primitive, the catalyst is rarely used, the product yield is low, and the fractionation process is relatively energy-consuming. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a production process of ethyl chloroformate.

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

[0006] A production process for ethyl chloroformate specifically comprises the following steps:

[0007] S1: placing anhydrous ethanol in a reactor and cooling it down;

[0008] S2: introducing phosgene into the reactor while maintaining the introduction temperature;

[0009] S3: After the phosgene is introduced, a low-temperature catalyst is added, and the mixture is heated to a reaction temperature and kept warm for reaction. After the reaction is completed, purification is performed to obtain the ethyl chloroformate.

[0010] Furthermore, the cooling temperature in step S1 is 0-8°C.

[0011] Phosgene has a low boiling point of about 8.2°C. Maintaining a low temperature can maintain the stability of the reaction raw materials and inhibit the reaction, preventing side reactions from occurring when the phosgene content is low.

[0012] Furthermore, the amount of phosgene used in step S2 is 1.2-1.4 times the amount of anhydrous ethanol, and the rate of introduction of phosgene is 2 mol·h -1 .

[0013] Excessive reaction substrate will promote the forward reaction and increase the reaction yield. Under the condition of excess phosgene, the main reaction will occur to produce ethyl chloroformate, but if anhydrous ethanol is excessive, a side reaction will occur to produce diethyl carbonate.

[0014] Furthermore, the introduction temperature in step S2 is 0-8°C.

[0015] Furthermore, in step S3, the reaction temperature is 25-35° C., and the insulation time is 15-45 min.

[0016] Furthermore, the purification method in step S3 is filtering, washing with ice water and drying.

[0017] The solid catalyst is removed by filtration and separated from the product; ethyl chloroformate is insoluble in water, while the reaction impurities are more soluble in water.

[0018] Furthermore, the amount of the low-temperature catalyst in step S1 is 1-10% of the mass of the anhydrous ethanol.

[0019] As the amount of catalyst increases, the number of Lewis acid centers in the system increases, the reaction rate increases, and the yield of the product increases; but excess catalyst will increase the viscosity of the reaction system, affect the mass transfer efficiency, and thus affect the product yield.

[0020] Furthermore, the preparation method of the low-temperature catalyst in step S1 is:

[0021] S1: Mix and grind the metal precursor and organic linker in equimolar amounts;

[0022] S2: Grinding evenly and reacting at high temperature, washing and drying after the reaction to obtain the low-temperature catalyst.

[0023] Furthermore, the reaction conditions in S2 are 130° C., 24 h.

[0024] Furthermore, the catalyst is a heterogeneous catalyst.

[0025] Catalysts can be divided into two categories: homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts such as concentrated sulfuric acid are evenly dispersed at the molecular level in the reaction system and can show higher catalytic activity, but are difficult to separate directly from the reaction system, which greatly increases the cost of post-processing. Heterogeneous catalysts can overcome the limitations of homogeneous catalysts and exist in the reaction system in solid form. The catalyst can be fixed in positions such as tower plates. It can be used as a filler to promote heat and mass transfer between gas and liquid phases, and can completely overcome the shortcomings of equipment corrosion and subsequent difficulties in separating the bottom product of the tower, avoid wastewater pollution to the environment, and can be regenerated for multiple uses.

[0026] Furthermore, the metal precursor in step S1 is a zirconium-containing compound and an aluminum-containing compound, and the metal molar ratio is 2:1-4:1.

[0027] An appropriate metal molar ratio can enhance the catalytic active sites of the catalyst, but when too much aluminum enhances the catalytic active sites of the catalyst, it will aggravate the carbon deposition effect and reduce the stability of the catalyst.

[0028] Furthermore, the organic linker in step S1 is a carboxylic acid.

[0029] Organic compounds containing carboxyl groups are more likely to coordinate with metal ions to form organic-inorganic hybrids, which usually have good catalytic activity and structural stability.

[0030] Furthermore, the low-temperature catalyst can be recovered and reused. The recovery method is: washing the filter residue after the reaction is completed with ethanol, and then drying it in an oven at 80°C.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Heterogeneous catalysts can overcome the limitations of homogeneous catalysts and exist in the reaction system in solid form. The catalysts can be fixed in positions such as tower plates. They can be used as fillers to promote heat and mass transfer between gas and liquid phases. They can also completely overcome the shortcomings of equipment corrosion and subsequent separation difficulties of tower bottom products, avoid wastewater pollution to the environment, and can be regenerated for multiple uses.

[0033] 2. Organic compounds containing carboxyl groups are more likely to coordinate with metal ions to form organic-inorganic hybrids, which have better catalytic activity and structural stability. DETAILED DESCRIPTION

[0034] In order to make the technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0035] Reagent Description:

[0036] Anhydrous ethanol, zirconium oxide, aluminum oxide, 1,4-terephthalic acid, analytical grade, Sinopharm Chemical Reagent Co., Ltd.

[0037] Preparation Example 1

[0038] Preparation of low temperature catalyst:

[0039] S1: 73.8 g zirconium oxide (0.6 mol), 10.2 g aluminum oxide (0.1 mol) and 116 g 1,4-terephthalic acid (0.7 mol) were ground at room temperature for 30 min;

[0040] S2: The uniformly ground solid was transferred to a Maffei furnace at 130° C. to react for 24 hours. After the reaction was completed, it was cooled to room temperature and washed with 50° C. anhydrous ethanol to obtain the low-temperature catalyst.

[0041] Example 1

[0042] S1: Place 46 g of anhydrous ethanol (1 mol) in a reactor and cool to 0-8°C in a cold water bath;

[0043] S2: Add 2 mol·h -1 1.3 mol of phosgene was introduced at a rate of 1.5 mol / s while maintaining the temperature;

[0044] S3: After the phosgene is introduced, 2.3 g of the low-temperature catalyst described in Preparation Example 1 is added, and the mixture is heated to 30° C. and maintained for 30 min. After the reaction is completed, the unreacted phosgene and hydrogen chloride are removed, and the mixture is filtered, washed with ice water three times, and dried with calcium chloride to obtain the ethyl chloroformate.

[0045] Example 2

[0046] The difference between this example and Example 1 is that the amount of zirconium oxide used in Preparation Example 1 is 0.4 mol.

[0047] The other parts are exactly the same as those in Example 1.

[0048] Example 3

[0049] The difference between this example and Example 1 is that the amount of zirconium oxide used in Preparation Example 1 is 0.8 mol.

[0050] The other parts are exactly the same as those in Example 1.

[0051] Example 4

[0052] The difference between this embodiment and embodiment 1 is that the amount of phosgene used in S2 is 1.2 mol.

[0053] The other parts are exactly the same as those in Example 1.

[0054] Example 5

[0055] The difference between this embodiment and embodiment 1 is that the amount of phosgene used in S2 is 1.4 mol.

[0056] The other parts are exactly the same as those in Example 1.

[0057] Example 6

[0058] The difference between this embodiment and embodiment 1 is that the amount of low-temperature catalyst used in S3 is 0.46 g.

[0059] The other parts are exactly the same as those in Example 1.

[0060] Example 7

[0061] The difference between this embodiment and embodiment 1 is that the amount of low-temperature catalyst used in S3 is 4.6 g.

[0062] The other parts are exactly the same as those in Example 1.

[0063] Example 8

[0064] The difference between this embodiment and embodiment 1 is that the reaction temperature in S3 is 25°C.

[0065] The other parts are exactly the same as those in Example 1.

[0066] Example 9

[0067] The difference between this embodiment and embodiment 1 is that the reaction temperature in S3 is 35°C.

[0068] The other parts are exactly the same as those in Example 1.

[0069] Example 10

[0070] The difference between this embodiment and embodiment 1 is that the reaction time in S3 is 15 min.

[0071] The other parts are exactly the same as those in Example 1.

[0072] Embodiment 11

[0073] The difference between this embodiment and embodiment 1 is that the reaction time in S3 is 45 min.

[0074] The other parts are exactly the same as those in Example 1.

[0075] Tests and Results

[0076] The yield of ethyl chloroformate is shown in Table 1.

[0077] Table 1

[0078] project Yield Example 1 96 Example 2 86 Example 3 92 Example 4 90 Example 5 95 Example 6 91 Example 7 96 Example 8 89 Example 9 90 Example 10 75 Embodiment 11 93

[0079] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A production process for ethyl chloroformate, characterized in that, The specific steps include: S1: placing anhydrous ethanol in a reactor and cooling it down; S2: introducing phosgene into the reactor and maintaining the introduction temperature; S3: After the phosgene is introduced, a low-temperature catalyst is added, and the mixture is heated to a reaction temperature and kept warm for reaction. After the reaction is completed, purification is performed to obtain the ethyl chloroformate; The preparation method of the low temperature catalyst is: T1: equimolar mixing of metal precursor and organic linker and grinding; T2: Grind evenly and then react at high temperature. After the reaction is completed, wash and dry to obtain the low-temperature catalyst.

2. A production process for ethyl chloroformate according to claim 1, characterized in that, The metal precursors in step T1 are zirconium-containing compounds and aluminum-containing compounds, and the metal molar ratio is 2:1-4:

1.

3. A production process for ethyl chloroformate according to claim 1, characterized in that, The organic linking agent in step T1 is a carboxylic acid.

4. A production process for ethyl chloroformate according to claim 1, characterized in that, The reaction conditions in T2 are 130° C., 24 h.

5. A production process for ethyl chloroformate according to claim 1, characterized in that: The temperature in S1 is lowered to 0-8°C.

6. A production process for ethyl chloroformate according to claim 1, characterized in that: The amount of the low-temperature catalyst used in step S1 is 1-10% of the mass of the anhydrous ethanol.

7. A production process for ethyl chloroformate according to claim 1, characterized in that: The amount of phosgene used in step S2 is 1.2-1.4 times the amount of anhydrous ethanol, and the rate of phosgene introduction is 2 mol·h -1 .

8. A production process for ethyl chloroformate according to claim 1, characterized in that, The introduction temperature in step S2 is 0-8°C.

9. A production process for ethyl chloroformate according to claim 1, characterized in that: The reaction temperature in step S3 is 25-35° C., and the insulation time is 15-45 min.

10. A production process for ethyl chloroformate according to claim 1, characterized in that: The purification method in step S3 is washing with ice water and drying.