Preparation technique of diphenyl guanidine
The invention belongs to thiofide.
The vulkacit D structural formula:
Vulkacit D is a kind of important thiofide, is used as plastics linking agent, thermally indicating material auxiliary agent in recent years again and connects building materials used additives etc.
The industrial production vulkacit D is existing historical for many years, u, s, p, and 2615045, Jiangsu chemical industry 1985, NO1, report is to adopt the mauguinite method among the P24, and mauguinite is hypertoxic gas, can cause that as equipment and pipe leakage the operator poisons, and be difficult to rescue.Domestic employing diphenyl thiourea method was once selected Pbo for use, ZnO, and Fe2O3 and oxygen-neutralized verdigris (O2-CuAc) are produced vulkacit D as sweetening agent.Reported the method for making sweetening agent with Pbo among the synthetic material auxiliary agent handbook P732 that Chemical Industry Press publishes, this method is to be recycled after Pbo is become Pbs.This method yield instability, the cost height, Lead contamination is serious, is difficult for industrialization.Reported zinc oxide method among the GerOffen481994,, the recycling problem of ZnS has been arranged also because ZnO is more expensive.Moreover synthetic vulkacit D need carry out two-step reaction, produces a large amount of hydrogen sulfide waste gas when generating the intermediate product diphenyl thiourea, and emit the SO2 contaminate environment when the recycling of ZnS.The spy opens among the clear 31-4673 and reports: in the presence of the ferric sesquichloride or oxidation high ferro of cheapness, make the method for vulkacit D with liquefied ammonia and aryl thiourea reaction, this method is used excessive liquefied ammonia, liquefied ammonia is promptly as reactant in reaction, also as solvent, its pressure is generally in the 0.7-1.5 MPa, and entire reaction course is to carry out under band pressure situation, brings many inconvenience to industrial production.
In order to solve to produce in the vulkacit D process environment is produced pollution problem, in order to reduce production costs special proposition the present invention.
The invention provides a new method of producing vulkacit D, this method is to synthesize vulkacit D with Fe2O3 as sweetening agent, the comprehensive utilization synthesizing thiourea of the H2S that emits during synthetic mesophase product diphenyl thiourea, not only solved the pollution problem of H2S to environment, and, paying and producing thiocarbamide is again important organic intermediate, can be used for the important intermediate of medicine, dyestuff, agricultural chemicals etc., also can be used as auxiliary agent in weaving, rubber, plastics industry.
The method applied in the present invention is: by aniline, dithiocarbonic anhydride, sulphur is the synthetic diphenyl thiourea of raw material, is the synthetic vulkacit D of sweetening agent again with Fe2O3, the H2S that emits when synthesizing diphenyl thiourea comprehensive utilization synthesizing thiourea.Method of the present invention has reduced the production cost of vulkacit D and thiocarbamide, has eliminated the pollution of H2S to environment.
Method principle of the present invention:
A, be the synthetic diphenyl thiourea of raw material with aniline, dithiocarbonic anhydride, sulphur
B, be sweetening agent with the oxidation high ferro, by the synthetic vulkacit D of diphenyl thiourea
C, the H2S that emits with a step reaction are the synthetic sulfuration of raw material urea
Reaction process of the present invention and condition:
1, synthetic diphenyl thiourea
Aniline and dithiocarbonic anhydride make diphenyl thiourea through washing, suction strainer, drying after condensation reaction under the pressure of 60-70 ℃ and 0.05 MPa, yield is more than 90%.
2, synthetic vulkacit D
In reactor, add diphenyl thiourea, be carried on Fe2O3 and ethanol on the r-Al2O3, logical liquefied ammonia in aforesaid liquid, press in making and reach 0.25 MPa, stop logical ammonia,, filter, add hydrochloric acid and make the vulkacit D hydrochloride 40-70 ℃ of reaction 6-10 hour, through neutralization, filtration, dry finished product vulkacit D, the yield 80% of getting.
3, by the hydrogen sulfide synthesizing thiourea
A, the H2S that will emit in the time of will synthesizing diphenyl thiourea purify (washing the organism of taking out of off) through aromatic hydrocarbons.
B, by solid: the liquor ratio value
※Be 1: the 2-5(weight ratio) add Ca(OH) 2 and water, under agitation add a part of CaCN2, absorb the H2S that emits among a slowly with negative pressure.
C, 20-50 ℃ of reaction 1 hour, add remainder CaCN2 again, continue reaction 3-5 hour at 60-90 ℃.
D, filtration, freezing, separate out the thiocarbamide crystal.
E, filtration, washing, the dry finished product thiocarbamide that gets, purity 〉=98%, yield are 80-90%.
※Solid-liquid ratio is elected smaller value as in this reaction, makes a gesture of measuring both to be beneficial to reaction and to carry out, and again can be directly freezingly from reaction solution goes out product, saves one step of evaporation operation than in the past.
Embodiment 1
A, synthetic diphenyl thiourea
In reaction flask, add 80 milliliters of aniline, 28 milliliters of dithiocarbonic anhydride, 108 ml waters, 0.1-0.4 restrains sulphur, is warmed up to 50-70 ℃, begins reaction, and emits H2S gas slowly.Reaction times is 5-6 hour, and reaction solution is after filtration, washing, drying make 91 gram diphenyl thioureas, 154-156 ℃ of product fusing point, and yield is more than 90%.
B, by the synthetic vulkacit D of diphenyl thiourea
In reaction flask, add 22,8 gram diphenyl thioureas, 100 gram Fe2O3 sweetening agents, 560 milliliters of dehydrated alcohols, logical ammonia, press in making and reach 0.25 MPa, stop logical ammonia, 40-70 ℃ of reaction ammonia excretion after 6-10 hour, steam ethanol, filter, add hydrochloric acid and regulate PH=2-5 and make the vulkacit D hydrochloride, neutralize, separate out vulkacit D with 10%NaOH, filtration, washing, dry 144-146 ℃ of the 17 gram vulkacit D fusing point that get.
C, synthesizing thiourea
To emit H2S gas among a, purify (removing the CS2 that does not have reaction) this arylamine by arylamine earlier and can select aniline, Tolylamine, xylidine etc. for use.
10 gram CaO are dissolved with 140 ml waters, add the CaCN2 of 30 grams 46.7%, feed H2S, 20-50 ℃ of reaction 1 hour, the CaCN2 that adds 20-40 gram again continues reaction 3-5 hour at 60-90 ℃, filters, with about 100 milliliters, 80 ℃ water washing filter cakes, filtrate is freezing with icy salt solution, separate out the thiocarbamide crystal, filtration, drying get thiocarbamide 21.3 grams, fusing point 175-176 ℃, purity is 98%.
