Central Glass Company, Limited

Yoshiyuki Kobayashi

Tamio Nakamura

Takashi Suenaga

Kenji Fujii

Yasushi Kita

Minoru Aramaki

Mitsuya Ohashi

Hisaji Nakano

Hiroaki Sakaguchi

Isamu Mouri

Shigenori Sakai

Tukasa Fujii

Takashi Suehaga

Takashi Yoneda

Takashi Yokoyama

The invention relates to a method of preparing a sulfonimide, a first salt thereof, or a second salt thereof. The method includes the step of: (a) reacting one or two sulfonyl fluorides with nonhydrous ammonia and an amine component which is one of a tertiary amine and a heterocyclic amine, so as to prepare the first salt. Alternatively, the method includes the step of: (a) reacting the sulfonyl fluoride with the amine component and a sulfonamide, so as to prepare the first salt. The method further optionally includes, after the step (a), the step of: (b) reacting, in an aqueous solution, the first salt with a metal compound, so as to prepare the second salt. The method still further optionally includes, after the step (a), the step of: (c) reacting the first salt with a strong acid so as to prepare the sulfonimide. Alternatively, the method further optionally includes, after the step (b), the step of: (d) reacting the second salt with a strong acid so as to prepare the sulfonimide. The sulfonimide, the first salt or the second salt is easily economically prepared in an industrial scale production with high purity and high yield.

Method of preparing sulfonimide or its salt

A process for producing methanesulfonyl fluoride involves reacting methanesulfonyl chloride, a metal fluoride and water to obtain a reaction product, subjecting the reaction product to distillation in the presence of water in an amount of 0.7 times or more the amount of the methanesulfonyl chloride to obtain a distillate. The distillate has a water layer and a methanesulfonyl fluoride layer. The distillate is subjected to phase separation to separate the methanesulfonyl fluoride layer from the water layer, and the methanesulfonyl fluoride is recovered.

Process for the production of high purity methanesulphonyl fluoride at

A process for refining a crude fluoroalkylsulfonic acid represented by the general formula RfSO.sub.3 H wherein Rf is a fluoroalkyl group having 1 to 4 carbon atoms into a highly refined one substantially free of impurities, said process comprising the steps of: (a) providing said crude fluoroalkylsulfonic acid, (b) mixing said crude fluoroalkylsulfonic acid with water or said water and an active silica to obtain a mixture, (c) stirring said mixture while maintaining said mixture at a higher temperature than room temperature, and (d) subjecting the mixture treated in said step (c) to distillation.

Process for refining crude fluoroalkylsulfonic acid with the use of water

A method of refining tungsten hexafluoride containing molybdenum hexafluoride as an impurity includes the step of contacting the tungsten hexafluoride with at least one metal selected from the group consisting of Mo, W, Cu, Ni, Fe, Co, Zn, Ti, Al, Ca and Mg at a temperature ranging from 100.degree. to 500.degree. C. Molybdenum hexafluoride is efficiently removed from the tungsten hexafluoride by the method.

Method of refining tungsten hexafluoride containing molybdenum

Carbon members contaminated with deposits of metals and/or metal compounds such as nitrides or carbides are thoroughly cleaned with little adverse influences on the carbon members themselves by treating the contaminated carbon members with a cleaning gas consisting of 1-20 vol % of CIF.sub.3 gas and the balance of an inactive diluent gas at a temperature in the range from 200.degree. to 300.degree. C. For example, this cleaning method is applicable to graphite parts of apparatus for forming thin films in the manufacture of semiconductor devices.

Method of cleaning carbon member contaminated with inorganic deposits

NF.sub.3 is prepared with good yields by reaction between fluorine gas and an ammonium complex of a metal fluoride, such as (NH.sub.4).sub.3 AlF.sub.6, in solid phase. The metal flouride ammonium complex may be one additionally containing an alkali metal, such as (NH.sub.4).sub.2 NaAlF.sub.6. The gas-solid reaction is carried out preferably at temperatures above 80.degree. C. and at relatively low partial pressures of fluorine in the gas phase of the reaction system, so that the reaction is easy to control.

Process of preparing nitrogen trifluoride by gas-solid reaction

A process of precipitating cryolite from a reaction solution given by mixing a sodium aluminate solution with a fluoride solution containing silica dissolved therein as impurity at reaction temperatures above 60.degree. C. To reduce silica content in the precipitated cryolite, the reaction solution is made to contain carbonate ions, 1-20 g/l as CO.sub.2, by introducing either carbon dioxide gas or a soluble carbonate into the fluoride solution Moreover, ignition loss of the cryolite can be decreased by preheating the sodium aluminate solution to 90.degree. C. or above.

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Ube, Japan

Yoshiyuki Kobayashi