Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
  • C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
  • C07D277/62—Benzothiazoles
  • C07D277/68—Benzothiazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
  • C07D277/70—Sulfur atoms
  • C07D277/72—2-Mercaptobenzothiazole

Definitions

• Mercaptobenzothiazole is known in the elastomer processing industry for its use as a vulcanization accelerator. It is also an important raw material in the synthesis of more sophisticated vulcanization accelerators adapted to the particular problems posed by the manufacture of articles as different as for example, tires, electric cables, shoe soles, shoe seals. insulation. It is also used for a large part in the synthesis of phytosanitary compounds.
• the impurities are extracted by treatment of the reaction product with carbon sulfide or an emulsion of carbon sulfide and water.
• the separation of volatile products can be carried out by distillation in a wide temperature range (100 to 300 ° C).
• this temperature is less than 220 ° C, the range of choice being 100 to 150 ° C.
• a thin film scraper evaporator is used which makes it possible to recover the solid product in powder form.
• the vacuum which it is necessary to maintain in the apparatus depends on the temperature chosen: it is generally between 1333 and 2.6664 pascal.
• the crude mercaptobenzothiazole to be purified obtained after distillation, is suspended in carbon tetrachloride or tetrachloro-1,1,2,2 ethylene.
• the crude reaction product is directly suspended in carbon tetrachloride or tetrachloro-1,1,2,2 ethylene.
• the recovery of recyclable products is carried out in this case by distillation of the solvent phase obtained after separation of the insoluble purified mercaptobenzothiazole.
• concentration of the solid product in suspension in the solvent it is preferred to limit the concentration of the solid product in suspension in the solvent to a value of between 200 and 400 grams per liter.
• concentration of the solid product in suspension in the solvent it is preferred to limit the concentration of the solid product in suspension in the solvent to a value of between 200 and 400 grams per liter.
• the dissolution of impurities is all the easier when the product to be purified is more finely divided. Any known means allows this condition to be easily achieved.
• the final recovery of the mercaptobenzothiazole is done by any known means of filtration and drying, without prior alkaline treatment.
• the solution resulting from filtration is subjected to a distillation so as to recover the tetrachloride or tetrachloro-1,1,2,2-ethylene and to separate the products to be recycled in whole or in part.
• reaction product of aniline, sulfur and carbon sulfide 1000 grams are taken, at the temperature of 180 ° C., at the outlet of a mercaptobenzothiazole synthesis reactor and after degassing of the hydrogen sulfide. , whose composition is as follows:
• This product is introduced into a scraper evaporator in which a temperature of 130 ° C. and a vacuum of 2 kPa are established.
• the solid product, extracted from the evaporator, ground, is suspended in 2300 ml of carbon tetrachloride, at a temperature of 25 ° C. After one hour of stirring, the suspension is filtered, washed with twice 300 ml of carbon tetrachloride, wrung and dried.
• the fraction containing aniline and benzothiazole can be recycled in the synthesis reactor without further treatment.
• the carbon tetrachloride solution containing the by-products is distilled so as to recover the recyclable solvent.
• a non-distillable fraction weighing 109 grams is collected; it can be recycled in the manufacture of mercaptobenzothiazole.
• the mercaptobenzothiazole subjected to purification is indifferently the crude product obtained according to any one of the known methods for its preparation; we can cite among others that of US Patent 1,631,871.
• Example 2 The procedure is as in Example 1 but using tetrachloro-1,1,2,2 ethylene. The results are identical.
• the mercaptobenzothiazole subjected to purification is indifferently the crude product obtained according to any of the known methods for its preparation.
• reaction product of aniline, sulfur and carbon sulfide the composition of which is as follows, are taken at 200 ° C., at the outlet of a mercaptobenzothiazole synthesis reactor:
• This product is introduced with stirring over approximately 30 minutes into 2000 ml of 1,1,2,2,2-ethylene tetrachloro maintained by cooling to the temperature from 20 to 25 ° C.
• Example 3 The process according to the invention, as illustrated by Example 3 given above, is compared to the process of the previously cited US patent 3,030,373. To this end, perchlorethylene is used as solvent in the process of Example 3. With regard to the American patent, carbon disulfide, perchlorethylene and benzene are used as solvents according to the process described in Example 1 of this patent.
• the process according to the invention which excludes the presence of water, makes it possible to obtain the mercaptobenzothiazole with a titer of 98.5%, higher than those obtained according to the previous process, ie 94.6%, 94.6% and 95.3% with the aforementioned solvents respectively.
• the process according to the invention has the advantage of being simpler as regards the number of treatments or manipulations (in particular, the preparation of mercaptobenzothiazole in the form sodium salt is not necessary) and as for technological installations.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Thiazole And Isothizaole Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1977
  • 1977-07-12 FR FR7721437A patent/FR2397409A1/fr active Granted
• 1978
  • 1978-06-27 CA CA306,303A patent/CA1097656A/fr not_active Expired
  • 1978-07-03 DE DE7878400052T patent/DE2860932D1/de not_active Expired
  • 1978-07-03 DK DK300378A patent/DK145821C/da not_active IP Right Cessation
  • 1978-07-03 EP EP78400052A patent/EP0000464B1/fr not_active Expired
  • 1978-07-06 US US05/922,417 patent/US4192804A/en not_active Expired - Lifetime
  • 1978-07-11 JP JP53084511A patent/JPS5811952B2/ja not_active Expired
  • 1978-07-11 ES ES471636A patent/ES471636A1/es not_active Expired
  • 1978-07-11 IE IE1396/78A patent/IE47028B1/en unknown
  • 1978-07-11 DD DD78206654A patent/DD137226A5/xx unknown
  • 1978-07-12 CS CS784667A patent/CS222268B2/cs unknown
  • 1978-07-12 IT IT68641/78A patent/IT1108498B/it active
  • 1978-07-12 SU SU782634049A patent/SU818482A3/ru active

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