CN1401636A - Novel preparation method of N, N' -diphenylthiourea - Google Patents

Abstract

The invention relates to the field of chemical raw materials. The product can be used as an intermediate of medicine and dye, a sulfur accelerator for natural latex and chloroprene rubber latex products, a heat stabilizer for polyvinyl chloride prepared by emulsion method, a metal corrosion inhibitor and an analytical reagent for elements such as ruthenium and osmium. Aniline and carbon disulfide are added to a container, and a macroporous sulfonic acid resin solid strong acid catalyst with an aniline dosage of 8 to 11% is used for stirring reaction at normal temperature and pressure. Both intermittent operation process and continuous process can be used, and the catalyst can be recycled and reused repeatedly; the reaction conditions are mild, the reaction can be completed at normal temperature and pressure, the required equipment is ordinary, no heating device is required, and no pressure-resistant equipment is required. When put into production, the equipment investment will be greatly reduced.

Description

Novel preparation method of N,N'-diphenylthiourea

Technical field

The invention relates to the field of chemical raw materials, in particular to a novel preparation method of N,N'-diphenylthiourea, the product can be used as an intermediate of medicine and dye, a thioaccelerator of natural latex and chloroprene latex products, and a polymer produced by emulsion method. Heat stabilizer for vinyl chloride, metal anti-corrosion and corrosion inhibitor and reagent for analysis and determination of elements such as ruthenium and osmium.

Background technique

There are several kinds of N, N'-diphenylthiourea synthesis methods reported in the existing literature. One is to use sulfur and ammonia as a catalyst, and at normal temperature, add 1% sulfur, 1% ammonium bicarbonate or ammonia water are used as catalysts, and the reaction is stirred and sealed. At room temperature, the reaction cycle is very long, about 15 days or more in summer. When the reaction temperature is controlled at about 40°C (close to the boiling point of carbon disulfide), the excess amount of carbon disulfide is much higher than that of the normal temperature method, and the production cycle is about 50 hours. Heating to 70°C, the reaction time is 10 hours; and when heated to 80°C, the reaction time can be shortened to 5 hours. But at this time, the consumption of carbon disulfide needs to be doubled in excess, the consumption of water also needs to be increased, and a relatively high pressure needs to be maintained in the reaction. (Ozaki S. Chem Rev, 1972, 72:457-462). The second is to use the ZnO/Al ₂ O ₃ complex as a catalyst. Ballabeni uses the ZnO/Al ₂ O ₃ complex as a catalyst to catalyze the reaction of amines and CS _2. For aromatic amines, N, N'-diphenylthiourea The yield reached 83%. However, the reaction still needs to be carried out at 100 °C, which is far beyond the boiling point of _CS2 . (Ballabeni M, Ballini R, Bigi F et al. J Org Chem, 1999 (64) 1029-1035). The third is to add additives or surfactants, using the "one-pot synthesis method" of additive triethanolamine, although the yield of N,N'-diphenylthiourea has reached 98%, but the large use of expensive additive triethanolamine and water makes This law is not economical. Adding additives can increase the yield of N,N'-diphenylthiourea to 85%-91%, but the reaction still needs to be carried out at 80°C. (Yuan Shujun, Fang Hailin. Fine Petrochemical, 1997, 5: 20-22)

The method for synthesizing N,N'-diphenylthiourea reported in the literature has a low product yield, and in order to increase the yield, the reaction generally requires heating. Since carbon disulfide is a volatile gas with a boiling point of 46.5°C, heating will inevitably increase its dosage or the reaction needs to be carried out under a higher pressure, which will cause inconvenience in operation.

Contents of the invention

The purpose of the present invention is to provide a new process for synthesizing N,N'-diphenylthiourea under normal temperature and pressure under mild conditions. The process uses a suitable catalyst so that the reaction does not require heating and pressurization.

The technical scheme that realizes the object of the present invention is as follows:

Adding aniline and carbon disulfide into a container to stir and react, is characterized in that a macroporous sulfonic acid resin solid strong acid catalyst with an aniline content of 8-11% is used.

It can be achieved through the following two processes:

One is to add the above-mentioned aniline, carbon disulfide, and macroporous sulfonic acid resin solid strong acid catalyst with an aniline dosage of 8 to 11% into a container connected with a condensing cooler, and after stirring and reacting, the product is extracted with ethanol in an extractor Separation to recover the solid strong acid catalyst, cooling the extract to room temperature and crystallizing to obtain white flaky N,N'-diphenylthiourea, and drying to obtain N,N'-diphenylthiourea.

The second is to continuously add the aniline, carbon disulfide, and macroporous sulfonic acid resin solid strong acid catalyst and solvent ethanol with an aniline amount of 8 to 11% in the continuous stirring reaction vessel, and then transfer the product directly to the extractor after the reaction is stirred by a continuous process Extract and separate in the medium, recover the solid strong acid catalyst, and then cool the extract to room temperature, crystallize a large number of white flaky crystals N, N'-diphenylthiourea, and dry N, N'-diphenylthiourea.

The stirring reaction mentioned above was carried out under normal temperature and pressure for 2 hours.

The melting point of the product measured by a melting point analyzer is 153.5-154°C, which is lower than the published value in the existing literature: 154-155°C; the theoretical value of the elemental analysis of the product is (C ₁₃ H ₁₂ N ₂ S): C 68.39, H 5.30, N 12.27, S 14.04; and the measured values: C 68.42, H 5.32, N 12.25, S 14.01 are very close. FTIR analysis (KBr pellet, ν=3208.1, 3035.4, 1598.1, 1551.4, 1492.9, 1450.2, 1342.1, 1240.1, 1070.2, 760.6, 696.9cm ^-1 ), UV analysis (λ _max =205, 280.5nm), H ¹ NMR (δ _H : 7.06-7.15 (2H, t), 7.25-7.27 (4H, t), 7.41-7.51 (4H, d), 9.01 (2H, s)).

Compared with the existing N, N'-diphenylthiourea production process, the present invention has the following advantages:

(1) The catalyst used is a solid acid catalyst, which can be recycled and reused;

(2) The reaction conditions are mild, normal temperature and pressure, the required equipment is ordinary, no heating device is required, and no pressure resistance is required

Equipment, if put into production, equipment investment will be greatly reduced;

(3) Since the reaction does not need heating, the loss of carbon disulfide will be reduced;

(4) Compared with the traditional process, the reaction time of the process of the present invention is greatly shortened, and the reaction is 2h, and N, N'-diphenylsulfide

The urea yield can reach 90%, and the product purity after crystallization exceeds 99.7%;

(5) This method does not use water as a solvent, nor does it add any additives, which saves precious water resources,

It also reduces production costs;

(6) This method can adopt the existing intermittent operation process and also can adopt the continuous process, so that the actual production

The production is easy to be automatically controlled, the operation is simple, and the production efficiency is improved.

Detailed ways

Embodiment one

In a 150mL round bottom flask, add 15mL aniline (0.16mol), 6mL carbon disulfide (0.10mol) and the macroporous sulfonic acid resin solid strong acid catalyst of 8.2% aniline consumption, the flask is connected with a condensing cooler, stirring and refluxing at normal temperature and pressure Reaction 2h. After the reaction, the product was transferred to a Soxhlet extractor with 100 mL of ethanol for extraction and separation, and the solid acid catalyst was recovered. After the extract was cooled to room temperature, a large amount of white flaky crystal N, N'-diphenylthiourea was crystallized in the extractor flask, and after vacuum drying at 80°C, 33.8 g of N, N'-diphenylthiourea was obtained by weighing. The yield is 89.9%, the purity measured by high performance liquid chromatography is 99.8%, and the melting point is 153.5-154°C.

Embodiment two

Add 10mL aniline (0.11mol), 5mL carbon disulfide (0.08mol) and sulfonic acid resin solid strong acid catalyst with 9.3% aniline consumption in a 150mL round-bottomed flask. . After the reaction, the product was transferred to a Soxhlet extractor with 100 mL of ethanol for extraction and separation, and the solid acid catalyst was recovered. After the extract was cooled to room temperature, a large amount of white flaky crystal N, N'-diphenylthiourea was crystallized in the extractor flask, and after vacuum drying at 80°C, 22.5 g of N, N'-diphenylthiourea was obtained by weighing. The yield is 90%, the purity measured by high performance liquid chromatography is 99.7%, and the melting point is 153.5-154°C.

Embodiment three

Continuously add 30mL aniline (0.32mol), 12mL carbon disulfide (0.20mol) and sulfonic acid resin solid strong acid catalyst of 10.1% aniline quality and 200mL solvent ethanol in a small single continuous stirring reaction pot, under normal temperature and pressure A continuous process was used to stir the reaction for 2h. After the reaction is over, all the products are transferred to a Soxhlet extractor for extraction and separation, and the solid acid catalyst is recovered. After the extract was cooled to room temperature, a large amount of white flaky crystal N, N'-diphenylthiourea was crystallized in the extractor flask, and after vacuum drying at 80°C, 42.6 g of N, N'-diphenylthiourea was obtained by weighing. The yield is 85.2%, the purity measured by high performance liquid chromatography is 99.6%, and the melting point is 153-154°C.

Claims (4)

1.N, the novel preparation method of N '-diphenylthiourea, adds aniline, carbon disulfide stirring reaction in container, it is characterized in that adopting the macroporous sulfonic acid resin solid strong acid catalyst of aniline consumption 8～11%. 2. according to claim 1, the novel preparation method of N '-diphenylthiourea is characterized in that the macroporous sulfonic acid resin solid strong acid catalyst of described aniline, carbon disulfide, aniline consumption 8～11% And put it into a container connected with a condensing cooler. After stirring and reacting, the product is extracted and separated with ethanol in an extractor to recover a solid strong acid catalyst, and then the extract is cooled to normal temperature and then crystallized to obtain white flaky crystals N, N'- Diphenylthiourea, after drying, N,N'-diphenylthiourea is obtained. 3. according to claim 1 described N, the novel preparation method of N'-diphenylthiourea is characterized in that in continuous stirring reaction vessel, add described aniline, carbon disulfide and aniline consumption 8～11% macropore continuously Sulfonic acid resin solid strong acid catalyst and solvent ethanol, after the continuous process of stirring and reacting, the product is directly transferred to the extractor for extraction and separation, and the solid strong acid catalyst is recovered. After cooling the extract to room temperature, a large number of white flaky crystals are crystallized N,N'-diphenylthiourea, N,N'-diphenylthiourea after drying. 4. The novel preparation method of N, N'-diphenylthiourea according to claim 1, characterized in that the stirring reaction is carried out under normal temperature and pressure for 2 hours.