Production process of cyanamide methyl formate

Abstract

The production process comprises the following steps: S1, placing cyanamide into a reaction container, and adding a solvent and a phase transfer catalyst into the reaction container; s2, raising the temperature to a reaction temperature, adding methyl chloroformate while stirring, and keeping the reaction temperature for reaction after the methyl chloroformate is added; and S3, after the reaction is finished, cooling to separate out crystals, dissolving the crystals in a hydrochloric acid solution, extracting, and distilling to obtain the cyanamide methyl formate. And the phase transfer catalyst is adopted, so that sufficient contact of cyanamide salts and methyl cyanamide formate with different polarities during reaction is facilitated, the reaction is promoted, the reaction yield is improved, and the method has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a production process of methyl cyanamide formate. Background Art

[0002] Methyl cyanocarbamate is an important intermediate in the synthesis of the pesticide fungicide carbendazim. After methyl chloroformate is prepared, cyanamide (H2N-CN) generated by the hydrolysis of lime nitrogen (Ca=N-CN) is used to carry out a cyanamination reaction to produce methyl cyanocarbamate.

[0003] There are two main methods for preparing methyl cyanamide, namely post-filtration method and pre-filtration method. The post-filtration method is to produce methyl cyanamide by directly adding methyl chloroformate as a deacidifying agent to produce methyl cyanamide without filtering the calcium hydrogen cyanamide produced by lime nitrogen and water, and then filtering to separate the residue. If the calcium hydrogen cyanamide solution is prepared by hydrolysis of lime nitrogen, it is filtered first to separate the residue, and then the calcium hydrogen cyanamide solution is reacted with methyl chloroformate in the presence of sodium hydroxide to produce methyl cyanamide. This is different from the previous method in the order of operation, and is called the pre-filtration method.

[0004] The residue of the first filtration method is not as toxic as the residue of the post-filtration method, and can be directly used as fertilizer in some areas. The methyl chloroformate consumed in production is about 10% less than that of the post-filtration method. Therefore, it is more reasonable in terms of process. At the same time, the first filtration method is more conducive to continuous production. In particular, in conjunction with the continuous production of methyl chloroformate, the production process is greatly shortened, the equipment is simplified, and the highly toxic material methyl chloroformate is converted into more stable, less toxic, and less corrosive cyanamide methyl formate once it is generated, and the production is safer. Therefore, the first filtration method is mostly used in process production. However, because methyl chloroformate is insoluble in water and cannot fully contact with calcium hydrogen cyanamide, the product yield is low. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a production process of methyl cyanamide formate. By using the method provided by the present invention to prepare methyl cyanamide formate, the reaction is sufficient and the yield is high.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A production process of cyanamide methyl formate comprises the following steps:

[0008] S1: placing cyanamide in a reaction vessel, adding a solvent and a phase transfer catalyst;

[0009] S2: After heating to the reaction temperature, add methyl chloroformate while stirring, and after the addition is completed, maintain the reaction temperature to react;

[0010] S3: After the reaction is completed, the crystals are cooled and precipitated, and the crystals are dissolved in a hydrochloric acid solution, extracted and distilled to obtain the methyl cyanamide formate.

[0011] Methyl cyanamide is prepared by the reaction of cyanamide and methyl chloroformate under alkaline conditions. Since methyl chloroformate is a colorless oily liquid, insoluble in water but soluble in organic solvents, a phase transfer catalyst is introduced in this reaction to allow for better and more complete contact between the molecules of cyanamide and methyl chloroformate.

[0012] Furthermore, the solvent in step S1 includes one or more of methanol, ethanol, acetone, and deionized water, preferably deionized water.

[0013] Furthermore, the molar ratio of cyanamide to methyl chloroformate is 2:1-3:1.

[0014] Increasing the amount of reactants will promote the positive shift of the reaction equilibrium, but excessive amounts will increase the complexity of post-processing.

[0015] Furthermore, in step S3, the methyl chloroformate is added by continuous dripping at a dripping rate of 0.2-0.4 mol·h -1 .

[0016] Methyl chloroformate is active in nature. If it is added all at once, the reaction will be too fast and cannot proceed fully. The dropwise addition method can allow methyl chloroformate to react fully, but if the speed is too slow, methyl chloroformate will volatilize and affect the product yield.

[0017] Furthermore, in step S2, the reaction temperature is 40-60° C., and the reaction time is 2-3 h.

[0018] Furthermore, the amount of the phase transfer catalyst in step S1 is 1-5% of the amount of the cyanamide salt substance.

[0019] Furthermore, the preparation method of the phase transfer catalyst is: dissolving a surfactant in deionized water, then adding a metal salt solution, mixing evenly, and then distilling off water in the mixed solution to obtain the phase transfer catalyst.

[0020] The ionic liquid catalyst is prepared, has good solubility for both organic and inorganic substances, has good thermal stability and chemical stability, is easy to separate from other substances, and can be recycled.

[0021] Furthermore, the surfactant is one or more of benzyltrimethylammonium chloride, polyethylene glycol, and sodium dodecylbenzene sulfate, preferably benzyltrimethylammonium chloride.

[0022] Furthermore, the metal salt is one or more of copper nitrate, nickel nitrate and palladium nitrate, preferably copper nitrate.

[0023] Copper can not only serve as a component of ionic liquids, but also act as a catalyst for the preparation of methyl cyanamide.

[0024] Furthermore, the molar ratio of the metal salt to the surfactant is 2:1-3:1.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The use of a phase transfer catalyst in the reaction helps cyanamide and methyl cyanamide formate with different polarities to fully contact each other during the reaction, thereby promoting the reaction and improving the reaction yield.

[0027] 2. Prepare ionic liquid catalysts, which have good solubility for organic and inorganic substances, good thermal stability and chemical stability, are easy to separate from other substances, and can be recycled.

[0028] 3. Metal ions not only serve as components of ionic liquids, but also act as catalysts for the reaction, further improving the reaction yield. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution 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.

[0030] Reagent Description

[0031] Cyanamide, methanol, ethanol, benzyltrimethylammonium chloride, polyethylene glycol, sodium dodecylbenzene sulfate, copper nitrate, nickel nitrate, palladium nitrate, analytical grade, Shanghai Aladdin Biochemical Technology Co., Ltd.

[0032] Preparation Example 1:

[0033] Preparation of phase transfer catalyst:

[0034] Take 0.1 mol of benzyltrimethylammonium chloride and dissolve it in deionized water. Then add 1 L of 0.25 mol·L -1 After the copper nitrate is added, stirring is continued for 1 hour, and then the water in the mixed solution is evaporated using a rotary evaporator to obtain the phase transfer catalyst.

[0035] Example 1

[0036] S1: 0.6 mol of cyanamide is placed in a reaction vessel, and 1 L of deionized water and 0.8 g of the phase transfer catalyst described in Preparation Example 1 are added;

[0037] S2: After heating to 50℃, stir and purify with 0.3mol·h -1 0.25 mol of methyl chloroformate was added dropwise at a rate of 100 μl and the reaction temperature was maintained to react after the addition was completed;

[0038] S3: After reacting for 2.5 hours, the mixture is cooled to room temperature to precipitate crystals, which are dissolved in a hydrochloric acid solution, and then extracted with ethanol and distilled to obtain the methyl cyanamide formate.

[0039] Example 2

[0040] The difference between this embodiment and embodiment 1 is that the surfactant described in preparation example 1 is polyethylene glycol.

[0041] The other parts are exactly the same as those in Example 1.

[0042] Example 3

[0043] The difference between this embodiment and embodiment 1 is that the surfactant described in preparation example 1 is sodium dodecylbenzene sulfate.

[0044] The other parts are exactly the same as those in Example 1.

[0045] Example 4

[0046] The difference between this embodiment and embodiment 1 is that the metal salt described in preparation example 1 is nickel nitrate.

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

[0048] Example 5

[0049] The difference between this example and Example 1 is that the metal salt described in Preparation Example 1 is palladium nitrate.

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

[0051] Example 6

[0052] The difference between this example and Example 1 is that the concentration of copper nitrate in Preparation Example 1 is 0.2 mol·L -1 .

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

[0054] Example 7

[0055] The difference between this example and Example 1 is that the concentration of copper nitrate in Preparation Example 1 is 0.3 mol·L -1 .

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

[0057] Example 8

[0058] The difference between this embodiment and embodiment 1 is that the amount of the phase transfer catalyst used in step S1 is 0.3 g.

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

[0060] Example 9

[0061] The difference between this embodiment and embodiment 1 is that the amount of the phase transfer catalyst used in step S1 is 1.3 g.

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

[0063] Example 10

[0064] The difference between this embodiment and embodiment 1 is that the amount of methyl chloroformate used in step S2 is 0.2 mol.

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

[0066] Embodiment 11

[0067] The difference between this embodiment and embodiment 1 is that the amount of methyl chloroformate used in step S2 is 0.3 mol.

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

[0069] Example 12

[0070] The difference between this embodiment and embodiment 1 is that the dropping speed of methyl chloroformate in step S2 is 0.2 mol·h -1 .

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

[0072] Embodiment 13

[0073] The difference between this embodiment and embodiment 1 is that the dropping speed of methyl chloroformate in step S2 is 0.4 mol·h -1 .

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

[0075] Embodiment 14

[0076] The difference between this embodiment and embodiment 1 is that the reaction temperature in step S2 is 40°C.

[0077] The other parts are exactly the same as those in Example 1.

[0078] Embodiment 15

[0079] The difference between this embodiment and embodiment 1 is that the reaction temperature in step S2 is 60°C.

[0080] The other parts are exactly the same as those in Example 1.

[0081] Example 16

[0082] The difference between this embodiment and embodiment 1 is that the reaction time in step S3 is 2 hours.

[0083] The other parts are exactly the same as those in Example 1.

[0084] Embodiment 17

[0085] The difference between this embodiment and embodiment 1 is that the reaction time in step S3 is 3 hours.

[0086] The other parts are exactly the same as those in Example 1.

[0087] Embodiment 18

[0088] The difference between this embodiment and embodiment 1 is that the solvent in step S1 is methanol.

[0089] The other parts are exactly the same as those in Example 1.

[0090] Embodiment 19

[0091] The difference between this embodiment and embodiment 1 is that the solvent in step S1 is ethanol.

[0092] The other parts are exactly the same as those in Example 1.

[0093] Comparative Example 1

[0094] The difference between this comparative example and Example 1 is that the methyl chloroformate in step S2 is added all at once.

[0095] The other parts are exactly the same as those in Example 1.

[0096] Tests and Results

[0097] The yield of methyl cyanamide formate is shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] 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 methyl cyanamide formate, characterized in that: The steps include: S1: placing cyanamide in a reaction vessel, adding a solvent and a phase transfer catalyst; S2: After heating to the reaction temperature, add methyl chloroformate while stirring, and after the addition is completed, maintain the reaction temperature to react; S3: After the reaction is completed, the crystals are cooled and precipitated, and the crystals are dissolved in an acid solution, extracted and distilled to obtain the methyl cyanamide formate.

2. A production technology for cyanamide methyl formate according to claim 1, characterized in that, The solvent in step S1 includes one or more of methanol, ethanol, acetone, and deionized water.

3. A production technology for cyanamide methyl formate according to claim 1, characterized in that, The amount of the phase transfer catalyst used in step S1 is 1-5% of the mass of cyanamide.

4. A production process for cyanamide methyl formate according to claim 3, characterized in that: The preparation method of the phase transfer catalyst is as follows: dissolving a surfactant in deionized water, then adding a metal salt solution, mixing the mixture evenly, and then distilling off water in the mixed solution to obtain the phase transfer catalyst.

5. A production process for methyl cyanamide formate according to claim 4, characterized in that: The surfactant is one or more of benzyltrimethylammonium chloride, polyethylene glycol, and sodium dodecylbenzene sulfate.

6. A production process for methyl cyanamide formate according to claim 5, characterized in that: The metal salt is one or more of copper nitrate, nickel nitrate and palladium nitrate.

7. A production process for methyl cyanamide formate according to claim 5, characterized in that: The molar ratio of the metal salt to the surfactant is 2:1-3:

1.

8. A production process for methyl cyanamide formate according to claim 1, characterized in that: The molar ratio of cyanamide to methyl chloroformate is 2:1-3:

1.

9. A production process for methyl cyanamide formate according to claim 1, characterized in that: The addition method of methyl chloroformate in step S2 is continuous dropwise addition at a dropwise addition rate of 0.2-0.4 mol·h -1 .

10. A production process for methyl cyanamide formate according to claim 1, characterized in that: The reaction temperature in step S2 is 40-60° C., and the reaction time is 2-3 h.

Images