CN1865241A - Ethyl carbamate and its preparation method - Google Patents

Abstract

This invention discloses a ethyl carbamate and method for making same. Wherein: mix the urea and ethanol with mole ratio of 1: 1-20, for sealed reaction with metallic oxide as catalyst, at 100-200Deg C, pressure 0.1-2.0MPa, reaction time 1-12h, and then obtain the ethyl carbamate. It is a non-light gas method, and can only produce ammonia gas during the production process, which can be recovered by absorption of cooling water for other usage, having benefits of no etching to the reactor, simple process, easy operation, non-pollution, low cost, high purity up to 95%, and good social and economical benefits.

Description

A kind of urethanum and preparation method thereof

Technical field:

The present invention relates to the pharmaceutical intermediate technical field, is a kind of urethanum and preparation method thereof specifically.

Background technology:

Urethanum (Carbamic este) has purposes widely, can be used as the intermediate of agricultural chemicals, medicine and organic synthesis etc., also is a kind of starting material of making colour candle.At present, the manufacture method of urethanum mainly is the phosgene synthesis method, and this method is because phosgene is deadly poisonous compound, and volatile, corrodibility is strong, and environmental pollution is very serious; Also have the isocyanic ester method, because carbamate is the synthetic prerequisite of isocyanic ester, in fact this method can only be the special method of preparation N-substituted carbamate; Also have carbonylation method, with organic amine, alcohol carbonylation reaction synthesis of carbamates class under the effect of catalyzer, but therefore the catalyzer that it adopted, is unfavorable for producing urethanum because poor to secondary amine.

Summary of the invention:

The objective of the invention is to overcome the deficiency of above-mentioned prior art, and a kind of urethanum is provided.

Another object of the present invention provides a kind of preparation method of urethanum.

Problems such as the present invention has mainly solved severe toxicity in the existing urethanum production, volatile, corrodibility strong, contaminate environment and production kind are single.

In order to achieve the above object, the present invention is achieved in that a kind of urethanum, it is to be mixed by 1: 1～20 molar ratio by urea and ethanol, confined reaction under the effect of catalyzer, catalyzer is a metal oxide, temperature of reaction is 100-200 ℃, and pressure is 0.1～2.0MP, and the reaction times is 1～12 hour.

A kind of urethanum of the present invention, its described metal oxide are any one in zinc oxide, manganese oxide, calcium oxide, aluminum oxide, the magnesium oxide.

The preparation method of urethanum of the present invention, it comprises following processing step:

A puts into reactor with ethanol, valve-off;

B adds urea in the reactor, after catalyzer being added, charging opening is sealed again;

C starts and stirs, and when reactor temperature rises to 100-150 ℃, opens condenser cooling water on the still, prepares ammonia excretion;

D when reactor temperature rises to 100-170 ℃, during pressure 0.1-2.0mPa, starts ammonia absorber, absorbs ammonia;

E, the beginning ammonia excretion is controlled at 100-200 ℃ with temperature of reaction kettle;

F keeps temperature in the kettle between 100-200 ℃, reacts the pressure release blowing 1-12 hour;

G when exquisite, in exquisite still, starts vacuum pump, and the still temperature rise is between 100-120 ℃, and distillation is flowed out until product-free, urethanum.

Compared with the prior art a kind of urethanum of the present invention and preparation method thereof has outstanding substantive distinguishing features and obvious improvement, 1, the invention belongs to non-phosgene synthesizing amino ethyl formate, adopting urea and ethanol is raw material, use easily separated and non-corrosive solid catalyst, only produce ammonia in the reaction process, can absorb through water of condensation and reclaim, be used for other aspects; Reaction raw materials is through reaction, corrosion reacting kettle not, and not discharging waste gas, waste residue in environment, reaction does not need high temperature, high pressure, safety coefficient is big, and the reactor slag is under the certain vacuum degree, and not polymerization can be melted down circulating reaction again, easy to clean, operation capable of circulation easily realizes automatic production; 2, raw material cheapness, by product is few, and reaction process is simple, and is easy to operate, avoided using hypertoxic Chemicals phosgene, pollution-free; 3, cost is low, and product yield can reach more than 95%, has good social benefit and economic benefit; 4, catalyzer is a composite catalyst, and is recyclable at a certain temperature; 5, continuity is strong, aspect distillation, adopts continuously uninterrupted distillation, saves energy consumption.

Embodiment:

In order to understand better and to implement, describe a kind of urethanum of the present invention and preparation method thereof in detail below in conjunction with embodiment.

Embodiment 1, opens alcohol meter measuring tank valve, and 780L ethanol is put into reactor, valve-off is opened the reactor charging opening again, and 150Kg urea is added in the reactor, after again the 10Kg Zinc oxide catalytic being added,, open and stir the step-down gear water coolant the charging opening sealing, start and stir, open the thermal oil terminal valve and heat up, when reactor temperature rises to 125 ℃, open condenser cooling water on the still, prepare ammonia excretion, when reactor temperature rises to 135 ℃, when pressure is 1.0mPa, start ammonia absorber, recycle pump absorbs ammonia, in the beginning ammonia excretion ammonia excretion process, utilize valve opening amount control ammonia excretion speed, temperature of reaction kettle is controlled at 150 ℃, keeps temperature in the kettle, react after 6 hours at 150 ℃, close thermal oil oil-feed valve, the pressure release blowing when exquisite, switches fuel feeding to exquisite still, start vacuum pump, still temperature rise to 110 ℃, distillation is flowed out until product-free, urethanum.

Embodiment 2, open alcohol meter measuring tank valve, and 780L ethanol is put into reactor, valve-off is opened the reactor charging opening again, and 120Kg urea is added in the reactor, after again the 20Kg magnesia catalyst being added,, open and stir the step-down gear water coolant the charging opening sealing, start and stir, open the thermal oil terminal valve and heat up, when reactor temperature rises to 100 ℃, open condenser cooling water on the still, prepare ammonia excretion, when the control reactor temperature is 100 ℃, when pressure is 0.1mPa, start ammonia absorber, recycle pump absorbs ammonia, in the beginning ammonia excretion ammonia excretion process, utilize valve opening amount control ammonia excretion speed, temperature of reaction kettle is controlled at 100 ℃, keeps temperature in the kettle, react after 12 hours at 100 ℃, close thermal oil oil-feed valve, the pressure release blowing when exquisite, switches fuel feeding to exquisite still, start vacuum pump, 100 ℃ of still temperature, distillation is flowed out until product-free, gets urethanum.

Embodiment 3, open alcohol meter measuring tank valve, and 800L ethanol is put into reactor, valve-off is opened the reactor charging opening again, and 150Kg urea is added in the reactor, after again the 15Kg calcium oxide catalyst being added,, open and stir the step-down gear water coolant the charging opening sealing, start and stir, open the thermal oil terminal valve and heat up, when reactor temperature rises to 150 ℃, open condenser cooling water on the still, prepare ammonia excretion, when reactor temperature rises to 170 ℃, when pressure is 1.0mPa, start ammonia absorber, recycle pump absorbs ammonia, in the beginning ammonia excretion ammonia excretion process, utilize valve opening amount control ammonia excretion speed, temperature of reaction kettle is controlled at 200 ℃, keeps temperature in the kettle, react after 1 hour at 200 ℃, close thermal oil oil-feed valve, the pressure release blowing when exquisite, switches fuel feeding to exquisite still, start vacuum pump, still temperature rise to 120 ℃, distillation is flowed out until product-free, urethanum.

Claims (3)

1, a kind of urethanum, it is to mix confined reaction under the effect of catalyzer by urea and ethanol by 1: 1～20 molar ratio, catalyzer is a metal oxide, temperature of reaction is 100-200 ℃, and pressure is 0.1～2.0MP, and the reaction times is 1～12 hour.

2, a kind of urethanum according to claim 1 is characterized in that described metal oxide is any one in zinc oxide, manganese oxide, calcium oxide, aluminum oxide, the magnesium oxide.

3, the preparation method of the described urethanum of claim 1, it comprises following processing step:

A puts into reactor with ethanol, valve-off;

B adds urea in the reactor, adds catalyzer simultaneously, and charging opening is sealed;

C starts and stirs, and when reactor temperature rises to 100-150 ℃, opens condenser cooling water on the still, prepares ammonia excretion;

D when reactor temperature rises to 100-170 ℃, during pressure 0.1-2.0mpa, starts ammonia absorber, absorbs ammonia;

E, the beginning ammonia excretion is controlled at 100-200 ℃ with temperature of reaction kettle;

F keeps temperature in the kettle between 100-200 ℃, reacts the pressure release blowing 1-12 hour;

G when exquisite, in exquisite still, starts vacuum pump, and the still temperature rise is between 100-120 ℃, and distillation is flowed out until product-free, urethanum.