Title of Invention

"AN IMPROVED PROCESS FOR THE ELECTROSYNTHESIS OF PARA-SEC. BUTYLANILINE"

Abstract

The present invention relates to an improved process for the preparation of p-sec. butyulaniline from p-sec. butyl nitrobenzene. In the process p-sec. butyl aniline having a formula C10H13NO2 is prepared from p-sec. butyl nitrobenzene in aqueous alcoholic-sulphuric acid medium by an electrochemical method. The Ti/TiO2 -ceramic electrode has the ability to reduce p-sec. butylnitrobenzene with good efficiency and the electrode is stable under the electro-chemical conditions whose surface behaves as a stable redox electron carrier and reduction occurs through heterogeneous redox catalysis.

Full Text

The present invention relates to An improved process for the preparation of p-sec. butylaniline from p-sec. Butylnitrobenzene. More particularly relates to an improved process for the preparation of p-sec. butylaniline, having a formula C10H13N02! from p-sec. butylnitrobenzene in aqueous-alcoholic-sulphuric acid medium by an electrochemical method. p-Sec. butylaniline is extensively used in perfumery industry, fine chemicals and dye stuff industries. It is used as a fixing agent and as a corrosion inhibitor. The industrially important p-sec. butylaniline is produced on an industrial scale by chemical method using hydrogenation catalyst. Hitherto p-sec. butylaniline has been prepared by chemical reduction method by using a Raney nickel surface catalyst under high pressure. In the chemical reduction method, p-sec. butylnitrobenzene is converted into p-sec. butylaniline with Raney nickel in the presence of hydrogen under high pressure. Besides Raney nickel, the other hydrogenative catalysts ( NaBH2S3, NaBH4, polysulfides etc.) are also used. In this method a bye-product is also obtained in substantial amount thus leading to separation or purification problem. In the electrochemical method aliphatic and aromatic nitro compounds are reduced to the corresponding amines at copper, carbon and Raney metal electrodes both in neutral and basic protic solutions. The yield of amine is less than 50% in the above techniques and in the cases where other reducing agents are used, have either low build up of hydrogen concentration or disposal of spent reagent involves pollution problem. The main objective of this invention is to develop a method for the preparation of p-sec. butylaniline from p-sec. butylnitrobenzene in good yield. Accordingly, the present invention provides an improved process for the preparation of p-sec. byutylaniline from p-sec. butylnitrobenzene which comprises reducing para sec. butyl nitro benzene characterized in that electrochernically in a divided cell by using Ti/TiO2 as ceramic cathode and lead as anode with an ion exchange series membrane as a separator in the presence of 5-10% sulphuric acid inverter as an anolyte and using 2-5 gm of para secondary butyl nitro benzene with 5-10% HjSC^ in alcohol to water ratio ranging from 70:20 to 70:30 as catholyte at a current density ranging in between 2-12 A/m2 of at a temperature in the range of 36 to 40°C, distilling out alcohol and obtaining the product by ethyl extraction from the catholyte. In an embodiment of the present invention the electrochemical reduction is carried out preferably at a current density ranging in between 2-10 amp/dm2. The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the invention. Example : 1 400 ml of aquous alcoholic (25:75) solution with 10% H2S04(v/v) containing 3gm of para secondary butyl nitro benzene was taken in a divided cell as a ca'iholyte and 300 ml of 10% H2S04 as an anolyte was taken in the above cell. Lead of surface area 0.4 dm2 and Ti/Ti02 of 0.4 dm2 was taken as a cathode and an anode respectively in the above said divided cell. The electrochemical reduction was carried out at a current density of 5 Adm2 , charge of 6F, cell voltage of 3.0 V and at a temperature of 38°C. The alcohol was disltilled our after completion of reduction and the catholyte was extracted with ether to obtain the final product. The yield was found to be 65%. The parameters involved involved in the above procedure is summarised below. Anode : Lead - 0.4 dm2 area Cathode : Ti/Ti02 - 0.4 dm2 area Anolyte : 300ml of 10% H2S04 Solution Catholyte : 400ml of aq. alcoholic (25:75) solution with 10% H2S04 (v/v) containing 3g of p-sec. butyl nitrobenzene Cell type : divided cell Diaphragm : "IONAC' series ion exchange membrane Current density : 5 A/dm2 Charge : 6 F Temperature : 38 °C Cell voltage : 3.0 V Current efficiency : 65 % Product yield : 65 % Example 2: The procedure is similar to example 1 except the following parameters Anode : Lead - 0.4 dm2 area Cathode : Ti/Ti02 - 0.4 dm2 area Anolyte : 300ml of 10% H2S04 Solution Catholyte : 400ml of aq. alcoholic(25:75) solution with 10% H2S04 (v/v) containing 3g of p-sec. butyl nitrobenzene Cell type : divided cell Diaphragm : 'IONAC' series ion exchange membrane Current density : 2 A/dm2 Charge : 6 F Temperature : 38 + 2 °C Cell voltage : 2.5 + 0.5 V Current efficiency : 78 % Product yield : 78 % Example 3: The procedure is similar to example 1 except the following parameters Anode : Lead - 0.4 dm2 area Cathode : Ti/Ti02 - 0.4 dm2 area Anolyte : 300ml of 10% H2S04 Solution Catholyte : 400ml of aq. alcoholic (25:75) solution with 10% H2S04 (v/v) containing 3g of p-sec. butyl nitrobenzene Cell type : divided cell Diaphragm : "IONAC' series ion exchange membrane Current density : 10 A/dm2 Charge : 6 F Temperature : 38 + 2 °C Cell voltage : 4.0 + 0.5 V Current efficiency : 70 % Product yield : 70 % Example : 4 The procedure is similar to example 1 except the following parameters Anode : Lead - 0.4 dm2 area Cathode : Ti/Ti02 - 0.4 dm2 area Anolyte : 300ml of 10% H2S04 Solution Catholyte : 400ml of aq. alcoholic 25:75) solution with 10% H2S04 (v/v) containing 3g of p-sec. butyl nitrobenzene Cell type : divided cell Diaphragm : 'IONAC' series ion exchange membrane Current density : 2 A/dm2 Charge : 12 F Temperature : 38 + 2 °C Cell voltage : 2.5 + 0.5 V Current efficiency : 35 % Product yield : 80 % Example : 5 The procedure is similar to example 1 except the following parameters Anode : Lead - 0.4 dm2 area Cathode : Ti/Ti02 - 0.4 dm2 area Anolyte : 300ml of 5% H2S04 Solution Catholyte : 400ml of aq. alcoholic (25:75) solution with 10% H2S04 (v/v) containing 3g of p-sec. butyl nitrobenzene Cell type : divided cell Diaphragm : VIONAC' series ion exchange membrane Current density : 5 A/dm2 Charge : 12 F Temperature : 38 + 2 °C Cell voltage : 3.0 + 0.5 V Current efficiency : 68 % Product yield : 68 % The main advantage of the present invention are 1. The formation of p-Sec. butylaniline is in high yield. 2. The selectivity for the reduction of p-Sec.butyl- nitrobenzene is high. 3. The Ti/Ti02 -ceramic electrode has the ability to reduce p-sec. butylnitrobenzene with good efficiency and the electrode is stable under the electro chemical conditions whose surface behaves as a stable redox electron carrier and reduction occurs through heterogeneous redox catalysis. 4. The Ti/TiC>2 ceramic electrode can be continuously reused and thus is highly economical. 5. Low cost of production of p-Sec. butylaniline 6. High solubility of p-sec. butyl nitro benzene in the above said alcohol:water mixture. 7. Temperature increase during the reaction is very small, thus avoiding side reactions and substrate loss. 8. High current efficiency for this electro-chemical reduction process than earlier reported process employing carbon, copper, nickel electrodes. 9. Eco friendly technology. We Claim: 1. An improved process for the preparation of p-sec. byutylaniline from p-sec. butylnitrobenzene which comprises reducing para sec. butyl nitro benzene characterized in that electrochemically in a divided cell by using Ti/TiO2 as ceramic cathode and lead as anode with an ion exchange series membrane as a separator in the presence of 5-10% sulphuric acid inverter as an anolyte and using 2-5 gm of para secondary butyl nitro benzene with 5-10% H2SO4 in alcohol to water ratio ranging from 70:20 to 70:30 as catholyte at a current density ranging in between 2-12 A/m2 of at a temperature in the range of 36 to 40°C, distilling out alcohol and obtaining the product by ethyl extraction from the catholyte. 2. An improved process as claimed in claim 1 wherein the electrochemical reduction is carried out preferably at a current density ranging in between 2-10 amp/dm2. 3. An improved process for the preparation of p-sec. butylaniline from p-sec. butylnitrobenzene substantially as herein described with reference to the examples.

Documents:

420-del-2001-abstract.pdf

420-del-2001-claims.pdf

420-del-2001-correspondence-others.pdf

420-del-2001-correspondence-po.pdf

420-del-2001-description (complete).pdf

420-del-2001-form-1.pdf

420-del-2001-form-18.pdf

420-del-2001-form-2.pdf

420-del-2001-form-3.pdf