The invention relates to a method for preparation of methyl carbamate. The method comprises the steps of: reacting urea with methanol in a reaction kettle to generate a reaction product containing methyl carbamate and ammonia; leading the ammonia out of the reaction kettle in batches, and at the same time, inputting the exported ammonia into a urea synthesis device as a raw material to react with carbon dioxide, thus generating urea again. Specifically, the charging mole ratio of urea to methanol in the reaction kettle is 1:6-10, the reaction in the reaction kettle occurs at 150-200DEG C, and the corresponding pressure in the reaction kettle is 1.5-2.0MPa. The method is characterized in that the methyl carbamate is prepared by taking urea and methanol as raw materials under intermediate temperature and pressure without catalyst, the rate of conversion from urea to methyl carbamate is improved, the production cost is reduced, and by means of the reaction converting the exported ammonia into urea, the greenhouse gas carbon dioxide is consumed, thus being beneficial to environmental protection. The invention also provides equipment for preparing methyl carbamate.

Method and equipment for preparation of methyl carbamate

The invention relates to a reaction process and a device for preparing organic carbonic ester by catalytic alcoholysis of urea. The invention provides a method for preparing carbamate or organic carbonic ester in the reaction process for preparing organic carbonic ester by catalytic alholysis of urea, which comprises the following steps: fatty alcohol and a reaction raw material are inputted inside a reactor, so the fatty alcohol and the reaction raw material pass through a reaction area inside the reactor to generate a reactant including ammonia inside the reaction are, the gas-phase substance mainly containing the ammonia is removed from the reaction area, the gas-phase substance mainly containing the gas-phase fatty alcohol is collected from the reaction area, and the gas-phase substance mainly containing the gas-phase fatty alcohol circularly reenters the reaction area. The invention also provides a device and a device for implementing the method.

Reaction process and system for preparing organic carbonic ester by catalytic alcoholysis of urea

The invention relates to a method for preparing methyl carhamate, which is mainly used for preparing the methyl carhamate. The preparation method mainly comprises the following steps: taking urea and methanol as raw materials, mixing a catalyst which has no corrosiveness on equipment and can be dissolved in the methanol, and a solvent with high boiling point in proportion, placing the mixture into a reaction kettle, performing synthesis reaction on the mixture for 8 hours in the reaction kettle at the temperature of between 130 and 160 DEG C and under the pressure of 0 MPa, synthesizing coarse products of methyl carhamate after reaction, obtaining semifinished products of methyl carhamate after performing distillation on the coarse products of methyl carhamate in an atmospheric distillation tower, removing light fractions, and performing centrifugal separation on the obtained products in a centrifuge, and obtaining pure products of methyl carhamate with the content of between 99.4 and 99.8 percent after performing vacuum distillation on the semifinished products at the pressure of between 2,600 and 2,800 Pa and collecting fractions at the temperature of between 70 and 80 DEG C. The products are widely used in the industries of medicaments, pesticides, rubber manufacture and the like.

Method for preparing methyl carhamate

The invention belongs to the field of food industry, and particularly relates to a separation method of a solvent of a phytoextraction mixture. The method comprises the following steps: a. adding the phytoextraction mixture to a solvent separation tank, and keeping the temperature of the phytoextraction mixture at 50 DEG C by injecting hot water into an interlayer of the solvent separation tank; b. continuously stirring by using a stirring assembly of the solvent separation tank; c. taking away the air in the solvent separation tank by a vacuum pump, so that the negative pressure is formed in the solvent separation tank; d. injecting an inert gas or nitrogen to the solvent separation tank, so that a solvent of the phytoextraction mixture is gasified under the action of negative pressure, and the inert gas or nitrogen rightly replaces a solvent gas; e. allowing the air taken away by the vacuum pump and the solvent gas to be liquefied under the action of a condenser, and allowing the liquefied solvent to reach a recovery tank; f. repeatedly injecting the inert gas or nitrogen into the solvent separation tank, and allowing the vacuum pump to continuously work to separate the solvent of the phytoextraction mixture; and g. taking the phytoextraction mixture out of the solvent separation tank. Compared with the prior art, the separation method provided by the invention has prominent substantive characteristics and remarkable progress, and the solvent separation rate is high.

Separation method of solvent of phytoextraction mixture

The invention discloses a chemical industrial purification apparatus. The apparatus which comprises a reduced pressure still and a gas drying tank is characterized in that: one end of the reduced pressure still is connected with a purification reaction solution, and the other end of the reduced pressure still is connected with a heat exchanger; one end of the heat exchanger is provided with a vacuum pump, and the other end of the heat exchanger is provided with a charging tank; an air pump is arranged between the reduced pressure still and the gas drying tank; and one side of the gas drying tank is provided with an air inlet. The apparatus of the invention, which has the of characteristics of simple technology and ingenious design, can be effectively applied to the chemical industrial field and has the advantages of purification efficiency improvement, simple structure, purification time shortening, energy saving and environmental protection, usage cost saving, flexible operation and novel design, is a new design scheme, and is in favor of the popularization usage.

Chemical industrial purification apparatus

The methyl carbamate producing process belongs to the field of fine chemical technology. The technological scheme of purifying methyl carbamate includes: dissolving urea in methanol to obtain methanol solution of urea of 0.01-10 mol/L concentration, reaction in reactor at 100-180 deg.c and 0.1-1.5 MPa for 0.5-10 hr, condensing in condensator to separate ammonia and making ammonia produce ammonia water, returning methanol with ammonia separated to the reaction system, and product purification. The present invention has high methyl carbamate yield, simplified operation, short reaction period, low power consumption and low cost.

Process for producing methyl carbamate

The utility model relates to a full closed fine chemical synthetic and separating device which is especially suitable for a synthetic and separating device of organic solvent comprising amino group The utility model has the technical proposals that the utility model comprises a raw material bin, a pump, a sluice valve and a reaction still, wherein the reaction still is in a full closed structure The reaction still is provided with a discharge port and an exhaust port, wherein the exhaust port of the reaction still is connected with a rectification device and a cooler The rectification device is connected with a condenser in bidirectional circulation, and the condenser is provided with a discharge pipe for exhaust gases A pre-reaction still is arranged between the raw material bin and the pump, the discharge port of the reaction still is connected with a purification device and the discharge pipe for exhaust gases is connected with a recovery device for exhaust gases The utility model has the advantages that the reaction still is additionally provided with the rectification device and a secondary separating device, so that the generated exhaust gases owing to reaction can be directly separated, recovered and reused, the added purification device of products can cause the purity of products to increase, the purification procedure at the later stage can be reduced, the production cost can be saved, the utility model is favorable for the enhancement of the conversion rate of reactant and a new product is formed

Full closed fine chemical synthesizing and separating device

The utility model relates to a purifier of fine chemicals. The utility model is especially suitable for the purifying separation of organic solvent in the class of comprising amino group. The utility model has the technical proposals that the utility model comprises a pressure reducing distillation kettle, an infusion pump, an air pump, pipe lines and a control valve, wherein the pressure reducing distillation kettle is a closed structure, the pipe line of the air pump which enters from the bottom of the pressure reducing distillation kettle is connected with a gas nozzle and the pipe line of the infusion pump which enters from the upper part of the pressure reducing distillation kettle is connected with a liquid nozzle. The upper part of the pressure reducing distillation kettle is also provided with a gas outlet pipe line after reaction, and the outlet pipe line is connected with a vacuum pump. The pipe line of the air pump is also provided with a gas drying tank and a gas heater. The outlet pipe line is also provided with a heat exchanger and a product collector. The utility model has the advantages of enhancing product purification rate, shortening purification time and reducing cost and energy consumption.

Zhang Zhaowen

Papers

Process for producing methyl carbamate

Full closed fine chemical synthesizing and separating device

Purifier of fine chemicals