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2891 results about "Phase-transfer catalyst" patented technology

In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the migration of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but insoluble in an organic phase in the absence of the phase-transfer catalyst. The catalyst functions like a detergent for solubilizing the salts into the organic phase. Phase-transfer catalysis refers to the acceleration of the reaction upon the addition of the phase-transfer catalyst.

Process for producing fluoroolefins

A process for producing a fluoroolefin of the formula: CF.sub.3CY.dbd.CX.sub.nH.sub.p wherein Y is a hydrogen atom or a halogen atom (i.e., fluorine, chlorine, bromine or iodine); X is a hydrogen atom or a halogen atom (i.e., fluorine, chlorine, bromine or iodine); n and p are integers independently equal to 0, 1 or 2, provided that (n+p)=2; comprising contacting, in the presence of a phase transfer catalyst, a compound of the formula: CF.sub.3C(R.sup.1.sub.aR.sup.2.sub.b) C(R.sup.3.sub.cR.sup.4.sub.d), wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently a hydrogen atom or a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine, provided that at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is halogen and there is at least one hydrogen and one halogen on adjacent carbon atoms; a and b are independently=0, 1 or 2 and (a+b)=2; and c and d are independently=0, 1, 2 or 3 and (c+d)=3; and at least one alkali metal hydroxide. The alkali metal hydroxide can be, for example, potassium or sodium hydroxide and the phase transfer catalyst can be, for example, at least one: crown ether such as 18-crown-6 and 15-crown-5; or onium salt such as, quaternary phosphonium salt and quaternary ammonium salt. The olefin is useful, for example, as an intermediate for producing other industrial chemicals and as a monomer for producing oligomers and polymers.
Owner:HONEYWELL INT INC

Tazobactam synthesis method

The invention relates to a tazobactam synthesis method which comprises the steps of: with 6-APA(Amino Penicillanic Acid) as raw material, preparing a key intermediate 6,6-dihydro penam sulphoxide acid diphenylcarbinol ester through successive reactions of esterification, oxidation, reduetive debromination and the like without separation; then, reacting with 2-triphenyl silicon-1,2,3-triazole; introducing a triazole ring; and finally obtaining the final product of tazobactam through potassium permanganate oxidation and metacresol deprotection. The tazobactam synthesis method is mainly characterized in that a phase transfer catalyst is introduced in the first step, therefore, the reaction rate and the product purity are improved; since an environment-friendly hydrogen peroxide-cobalt acetate catalytic oxidation system is adopted in the third step, the characteristics of good reaction selectivity, high yield, catalyst recyclability and the like are achieved; a method for synthesizing 2 alpha-methyl-2 beta-(1,2,3- triazole-1- radical) methyl penam-3 alpha-carboxylic acid diphenylcarbinol ester by using 2-triphenyl silicon-1,2,3-triazole is adopted in the fifth step, and the tazobactamsynthesis method is simple and convenient to operate, is safe and reliable, shortens the reaction route and improves the total yield. Compared with the traditional process, the tazobactam synthesis method greatly reduces the production cost and the environment pollution and has greater implementation value and economic benefits.
Owner:YIYUAN XINQUAN CHEM

Topical film delivery system

The described invention provides a topical bioadhesive film-forming pharmaceutical composition formulated for application directly to skin or to a substrate. The composition includes a therapeutic amount of an active agent; and one or more excipients selected from the group consisting of a non-cellulosic polymer or copolymer, a film forming agent, a plasticizer, a permeation enhancer, an antioxidant, a preservative, a solubilizer, a phase transfer catalyst, a viscosity modifier, a vitamin, a mineral nutrient, a solvent, a colorant and a fragrance. It further provides a delivery system comprising the composition and a means for administering the composition. It also describes uses of the delivery system in the manufacture of a medicament for treating a skin condition, disease or disorder, and a method for treating a skin condition, disease or disorder with the composition. The composition is characterized by: controlled release. The formed film is characterized by: locally sustained levels of a minimum effective concentration (MEC) of the active agent between applications; its adherence and conformance to a surface of the skin; its pliability, its resistance to breaking under tension (tensile strength); maintained potency of the active agent; and removability of the film from the skin without a residue.
Owner:SIDMAK LAB INDIA PVT LTD

Preparation method of polyvinylidene fluoride grafted p-styrenesulfonic acid proton exchange membrane

The invention provides a preparation method of a polyvinylidene fluoride grafted p-styrenesulfonic acid proton exchange membrane. The method comprises the following steps of: firstly, adding a phase transfer catalyst into a prepared alkaline alcohol solution to obtain an alkaline alcohol solution containing the phase transfer catalyst; adding polyvinylidene fluoride into the solution and processing to obtain alkaline-treatment polyvinylidene fluoride powder; adding the obtained powder into an organic solvent to obtain an alkaline-treatment polyvinylidene fluoride powder solution; adding a p-styrene sulfonate monomer and an initiator, and reacting in a nitrogen atmosphere; performing ultrasonic oscillation, and putting the product in a polytetrafluoroethylene membrane frame; drying and stripping the membrane; replacing the monovalent cations in the membrane; removing the residual sulfuric acid; and storing the product in the deionized water to obtain the polyvinylidene fluoride grafted p-styrenesulfonic acid proton exchange membrane. Through the method, a proton exchange membrane with high electric conductivity can be prepared, and the electric conductivity is relatively approximate to that of a Nafion membrane; and the preparation method is simple and easy to implement, has relatively low cost and can be applied to large-scale production.
Owner:HUBEI UNIV
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