Title of Invention

AN IMPROVED PROCESS FOR PREPARATION OF TRIAZOPHOS

Abstract

The present invetion reletes to a process of manufacturing triazophos using phase transfer catalyst in hich yieild and purity. The process comprising sbstituted 1-phenyl 3-hydroxy-1, 2, 4-triazole with 0, 0-diethylthiophosphoryl chloride in the presence of acide scavengers such as tertiary amines, inorganic bases and hydroxides of potassium ad sodium, carbonates of sodium and 0.2% to 2.0% phase transfer catalyst such as tetra-butyl ammonium bromid, triethylbenzylammonium chloride or triethylenediamine at temperature between 20-45 c in suitable solvents such as water then cooling the reaction mixture to 25-30 c, separating out the aqueous layer and the organic layer so formed, extracting aqueous layer with 300 grams of solvents such as xylene, monochlorobenzen, dmf, toluene methylene dichloride, ehthylene dichloride and water for complete recovey ofo triazophos; adding this wxtracts to the organic layer, washing the organic layer with suitable solvents and recvering triazophos of at least 92% purity.arrying out this step at the ambient temperature of 20-45C more particularly 20-30C and and atmospheric pressure.

Full Text

FORM 2 THE PATENT ACT 1970 & The Patents Rules, 2003 - / COMPLETE SPECIFICATION (See section 10 and rule 13) 1. TITLE OF THE INVENTION "AN IMPROVED PROCESS FOR PREPARATION OF TRIAZOPHOS' 2. APPLICANT (a) NAME SUDARSHAN CHEMICAL INDUSTRIES LTD. (b) NATIONALITY : An Indian company registered under the provisions of of the Companies Act, 1956 (c) ADDRESS 162, Wellesley Road, PUNE-411 001. Maharashtra State, India 3. PREAMBLE TO THE DESCRIPTION PROVISIONAL The following specification describes the invention. / COMPLETE The following specification particularly describes the invention and the manner in which it is to be performed. 4. DESCRIPTION : Starts from page 2. 5. CLAIMS : 6 claims given on page nos.f & 8. 6. DATE AND SIGNATURE : Page No.7 of the Complete Specification. 7. ABSTRACT OF THE INVENTION : Qivefl Q& separate page The present invention relates to an improved process for preparation of Triazophos. More particularly, the present invention relates to a process for manufacturing of Triazophos using 0.02% to 2% one-phase transfer catalysts in high yield and at least 92% purity. Triazophos having insecticidal and acericidal properties used for fighting against different type of plant and animal pest. Prior or Present Art: In the prior art, triazophos prepared in two steps in 81.02% yield from Urea and phenyl hydrazine. tertiary amines, inorganic bases sodium and potassium in suitable It is further known that Triazophos is made by reacting 1-phenyl 3-hydroxy-1, 2,4-triazole with 0,0-di-ethyl thiophosphoryl chloride using acid scavengers such as and hydroxides of potassium and sodium, carbonates solvents at reflux temperature of 50-90°C. It is further known that triazophos is synthesized from reaction of 1-phenyl -3-hydroxy - 1,2,4-triazole with 0,0- diethylthiophosphoryl chloride in orgamc solvent in presence of catalyst. It is further known that the synthesis of triazophos, prepared in two steps, results to give at least 81.02% yield from urea and phenyl hydrazine which is taken from a Chinese "The Chemical Industry research of Fubang,inyang 464000,Peop.Rep.China)'The above-mentioned processes mentioned in the prior or present art have the following drawbacks: 1. The said processes requires large excess of solvent. 2. The said processes create effluent problems. 2 3. Reaction is carries out at higher temperature conditions of 50-90°C, which is detrimental to the active ingredient as triazophos deteriorates at higher temperature conditions. It is the object of present invention to manufacture triazophos using phase transfer catalysts in high yield and purity. Yet another abject of the present invention is to carrying out the reaction in water, to avoid hazardous organic solvents such as Acetone, Dioxan, Tetrahydrofuron, methyl ethyl keton, benzene, toluene, mono chloro benzene, acetonilrile etc. so as to make process safer and environment friendly. According to this invention, therefore, a process for manufacturing triazophos of the formula I as given, where R is phenyl group: comprising reacting substituted 1-phenyl -3-hydroxy - 1,2,4-triazole with o, o-diethyl thiophosphoryl chloride in the presence of acid scavengers and 0.02% to 2.0% phase transfer catalysts such as herein described at a temperature between 20° C to 45°C in suitable diluents preferably a water, then cooling the reaction mixture to 25°C to 30°C, subsequently separating out the aqueous layer and the organic layer so formed then the said aqueous layer is extracted with 600 grams of solvents such as herein described for complete recovery of triazophos adding this extract to the organic layer, washing the organic layer with suitable solvents such as herein described and triazophos of at least 92% purity is recovered, carrying out this step at ambient temperature of 20-45 °C more particularly 20-30°C and atmospheric pressure. An improved process for preparation of triazophos requires minimuml.O mole of l-phenyl-3-hydroxy triazole, 1.0 to 1.05-mole o-o-di-ethyl MOrl)hosphoryl chloride, 1.0 to 1.5 moles per moles acid scavengers such as Sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate. Suitable solvents used are such as xylene, monochlorobenzene, DMF, toluene methylene dichloride and ethylene dichloride. Water is preferred solvent due to cost effectiveness and green chemistry. Phase transfer catalysts (PTC) such as tetra-butyl ammonium hrnmidfL^fri-ethvl-benzyl- ammonium chloride, and tri-ethylene^di-amine are used. Temperature of the reaction should be between 20 ° C to 45 ° C depending upon the reaction conditions and solvents. Addition of 0,0-di-ethyl thio-phosphoryl chloride in reaction mass, containing l-phenyl-3 -hydroxy triazole, acid scavengers, and phase transfer catalysts and solvents is being carried out within 3 to 5 hours at normal atmospheric pressure. The reaction time of the present invention depends upon quantity of l-phenyl-3-hydroxy triazole, acid scavengers, phase transfer catalysts and solvents used. The following example illustrate the invention: Synthesis of Triazophos 161 grams (l.Omole) l-phenyl-3-hydroxy-1, 2,4- triazole (minimum purity = 96%) is taken in 2 liter four neck round bottom flask fitted with thermometer packet, addition funnel, water condenser and mechanical stirrer. 483 _gram water,_5gm £0.01^55, mole) tetra butyl ammonium bromide_are_addgd inthe reaction mix along with1,45 ,gm (1.05 mole) potassium carbonate at 20°C-25°C . 198 grams (1.05 moles) 0,0-di-ethyl-thiophosphryl chloride is added in the reaction mix. Maintaining temperature 20-45 degree C. Addition of 0,0-di-ethyl-thiophospheryl chloride is carried out within 3 hours. Reaction is monitored by checking unreacted di-etiTyl-tinojhosphjtyl cUorid&ciintent. 4 Reaction mixture is cooled to 25 to 30 °C. Aqueous layer and organic layer are completely separated out. Aqueous layer is extracted with 300 grams toluene for complete recovery of triazophos. Extract is added in organic layer, which is washed with 300grams water. Washed organic layer is taken fojjj^Qix&tyja£^ahi£axL^292 grams (93.29%) of triazophos having purity of at least 92% is obtained. Column Injector Temp. Detector Temp. Oven Temp. Internal Std.. Wtof TZP Std. Wt.ofInt.Std. Elution ANALYTICAL METHOD FOR DETERMINATION OF PURITY OF TRIAZOPHOS Principle :- Triazophos (TZP) content is determined using an internal standard method on a Gaschromatogram (GC). G. C.Conditions - 5% OV-210 240°c 250°c 230°c (Isothermal) Decyclohexyl Phthalate (DCP) 0.25 gms 0.10 gms Chloroform Triazophos Internal Standard (DCP) Reagents Details :-a] 1. Std. Reference Triazophos of known purity. 2. Dicyclohexyl Phthalate (Internal standard) 3. Chloroform (A.R.Grade) Determination of Factor - Weigh accurately about 0.08 to 0.10 gms DCP (Internal Standard) in a 10 ml volumetric flask. Weigh accurately about 0.25 to 0.30 gms of std. Ref. Triazophos in same flask. Dilute to 10 ml with Chloroform. Inject 1 microltr. sample in GC. 5 b] Weigh accurately about 0.10 of DCP (Internal Standard) in a 10 ml volumetric flask. Weigh accurately about 0.25 to 0.30 gms of Triazophos in same flask. Dilute to 10 ml with Chloroform. Inject 1 microltr. sample in GC. Calculations :- 1. Response Factor - P t _ %TZP(Std) x Area of DCP (IntStd) x Wt. of Sample Wt of DCP x Area of Sample 2. % Assay Triazophos - o/ T7P — Factor x Wt. of DCP (IntStd) x Area of Sample Area of DCP x Wt. of Sample Calculations:- Expt.#RDR/17/SSP/88 1. Response Factor - P t _ %TZP(Std) x Area of DCP flntStd) x Wt of Sample Wt. of DCP x Area of Sample Factor = 41.6x66.972x0.2123 0.1012x33.028 Factor = 176.96 3. % Assay Triazophos - _ Factor Std) x Area of DCP (Int.Std) x Area of Sample Area of DCP x Wt. of Sample %TZP= 176.96x0.1012x45.129 54.871 x 0.1600 %TZP= 92.06% To sum up the following advantages are achieved: 1. The present invention is carried out preferably in water, and thus hazardous organic solvent are avoided. 2. It is very safe and environmental friendly. 3. It is very cost effective as reaction is carried out in water. 4. Triazophos obtained by this process is relatively more stable as the reaction is carried out at ambient conditions. 6 We Claim: 1. A process for manufacturing triazophos of the formula I as given, OC2H5 (Fonmila I) where R is phenyl group: comprising reacting substituted 1-phenyl -3-hydroxy - 1,2,4-triazole with o, o-diethyl thiophosphoryl chloride in the presence of acid scavengers and 0.02% to 2.0% phase transfer catalysts such as herein described at a temperature between 20° C to 45°C in suitable diluents preferably a water, then cooling the reaction mixture to 25°C to 30°C, subsequently separating out the aqueous layer and the. organic layer so formed then the said aqueous layer is extracted with 600 grams of solvents such as herein described for complete recovery of triazophos adding this extract to the organic layer, washing the organic layer with suitable solvents such as herein described and triazophos of at least 92% purity is recovered, carrying out tETstep at ambient temperature of 20-45 °C more particularly 20-30°C and atmospheric pressure. 2. A process as claimed in claim (1) wherein phase transfer catalysts are tetra-butyl ammonium bromide, triethylbenzylammonium chloride and triemylenediamine. 3. A process as claimed in claim (1) wherein suitable solvents are xylene, choloro-benzene, DMF. 4. A process as claimed in claim (1) wherein acid scavengers are Sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate. 5. A process as claimed in claim (1) wherein acid scavengers are required is in the concentration of 1.0 to 1.5 moles per mole of 1-phenyl -3-hydroxy - 1,2,4-triazole. 7

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