Korea Institute of Science and Technology

Kun You Park

Byoung Sung Ahn

Moon Jo Chung

Hoon Sik Kim

Byung Gwon Lee

Dong Ju Moon

Young Soo Kwon

Jong Sung Lim

Sang Deuk Lee

Hong Gon Kim

Honggon Kim

Seong Joon Cho

Hyung Sun Kim

Seong M Jo

Byung Won Cho

Won Il Cho

Wha Seop Lee

Jong-sung Lim

Kyung Suk Yun

Byung-Gwon Lee

Chang-Nyeon Kim

Jung Hwan Song

Suk Won Chun

Sang-deuk Lee

Jai Jun Kim

Un Seok Kim

Seok Ku Ko

Sung Won Choi

The present invention provides a lithium secondary battery and its fabrication method. More particularly, the present invention provides a lithium secondary battery comprising a super fine fibrous porous polymer separator film and its fabrication method, wherein the porous polymer separator film is fabricated by the following process: a) melting at least one polymer or dissolving at least one polymer with organic solvents to obtain at least one polymeric melt or at least one polymeric solution; b) adding the obtained polymeric melt or polymeric solution to barrels of an electrospinning machine; and c) discharging the polymeric melt or polymeric solution onto a substrate using a nozzle to form a porous separator film. The lithium secondary battery of the present invention has the advantages of better adhesion with electrodes, good mechanical strength, better performance at low and high temperatures, better compatibility with organic electrolyte solution of a lithium secondary battery.

Lithium secondary battery comprising a super fine fibrous polymer separator film and its fabrication method

A refrigerant composition that can be a substitute for chlorodifluoromethane (HCFC-22) comprises: (a) a first constituent of difluoromethane, (b) a second constituent of 1,1,1-trifluoroethane, (c) a third constituent of 1,1,1,2-tetrafluoroethane, and (d) a fourth constituent selected from the group consisting of 1,1-difluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,3,3-hexafluropropane and butane.

Refrigerant composition comprising difluoromethane, 1,1,1-trifluoroethane and 1,1,1,2-tetrafluoroethane

A novel refrigerant composition useful as a substitute for HCFC-22, comprising a first constituent of difluoromethane (CH F , HFC-32); a second constituent of pentafluoroethane (CHF CF , HFC-125); a third constituent of 1,1,1-trifluoroethane (CH CF , HFC-143a); a fourth constituent selected from the group consisting of cyclopropane (C H , RC-270), 1,1,1,2,3,3,3-heptafluoropropane (CF CHFCF , HFC-227ea), 1,1,1,2,2-pentafluoropropane (CH CF CF , HFC-245cb), isobutane (CH(CH ) CH , R-600a), octafluorocyclobutane (C F , RC-318), 1,1,1,2,3,3-hexafluoropropane (CHF CHFCF , HFC-236ea), butane (C H , R-600), bis(difluoromethyl)ether (CHF OCHF , HFE-134) and pentafluoroethylmethylether (CF CF OCH , HFE-245).

Refrigerant mixture comprising difluromethane, pentafluroethane and 1,1,1-trifluoroethane

The present invention relates to a catalyst for producing 1,1-difluoroethane (HCFC-152a) and producing method thereof. More particularly, it is to provide the catalyst prepared by impregnating palladium on the active carbon pretreated with an aqueous hydrogen fluoride solution and an aqueous hydrogen chloride solution in series and its use in the production of 1,1-difluoroethane (HCFC-142b) by dehydrochlorinating 1,1-difluoro-1-chloroethane at 240-300&deg; C. in the supplying molar ratio of 2-6 (H /HCFC-142b) with maximizing a selectivity toward the product of HCFC-152a.

Catalyst and method for producing 1,1-difluoroethane

The present invention relates to a catalyst characterization apparatus, and in particular to an improved catalyst characterization apparatus which is capable of characterizing the surface of a catalyst more accurately by a volumetric method without requiring a pre-treatment step which may vary the characteristics of the catalyst as well as without exposing the catalyst in air, by combining a dynamic flow type reactor with a volumetric type adsorption apparatus, whereby it is possible to accurately characterize the catalyst during an actual reaction. It is possible to accurately characterize the various catalysts and to characterize the catalyst during the reaction, alternately and/or continuously, by combining a dynamic flow type reactor with a volumetric type characterization apparatus as well as a dynamic flow type characterization apparatus.

Catalyst characterization apparatus

A refrigerant composition useful as a substitute for chlorodifluoromethane (CHCIF,, HCFC-22). The refrigerant mixture has a first constituent of difluoromethane (CH,F,, HFC-32); a second constituent selected from perfluoropropane (C,F8, PFC-218), cyclopropane (C,H6, RC-270) and butane (C,H,, R-600); and a third constituent selected from 1,1-difluoroethane (CH,CHF,, HFC-152a), 1,1,1,2,2-pentafluoropropane (CH,CF,CF3, HFC-245cb) and bis(difluoromethyl)ether (CHF,OCHF,, HFE-134).

Refrigerant mixture substitute for chlorodifluoromethane

The present invention relates to a method for preparing alkylene carbonate by reacting alkylene oxide with carbon dioxide in the presence of a catalyst system comprising:

Preparation of alkylene carbonate using indium halides and mixtures of

A method for concurrently producing different hydrofluoro carbons, comprising the reaction of halocarbon or hydrohalocarbon with hydrogen fluoride in a reaction system consisting of a series of at least two discrete reactors, in the presence of catalysts, said reactors each being provided with different reactant materials and differing in reaction conditions including the catalysts and/or reaction temperature, thereby flexibly controlling their production rates in accordance with fluctuations in their demand, and eliminating the risk of constructing large scale plants responsible for individual hydrofluorocarbons.

Method for concurrently producing different hydrofluoro carbons

The present invention relates to a process for manufacturing 1,1,1,2-tetrafluoroethane (HFC-134a) from trichloroethylene (TCE) and hydrogen fluoride (HF) by reacting the HCFC-133a with the HF to produce the HFC-134a and reacting the TCE with the HF to produce 1-choro-2,2,2-trifluoroethane (HCFC-133a), characterized by that a part of said HF is mixed with the mixture containing the HFC-134a and the remaining portion of said HF is fed with said TCE in portions to at least two sections of a reactor for producing said HCFC-133a. According the present process, the temperature change in the reactor for producing HCFC-133a is maintained within a narrow range over the whole reaction procedures, and the catalytic activity is well maintained. Further, the formation of by-products is considerably prevented and thus the productivity is remarkably enhanced.

Process for manufacturing 1,1,1,2-tetrafluoroethane

There is a process for removing moisture from chlorodifluoromethane (CHClF.sub.2) containing moisture in excess in the preparation of chlorodifluoromethane comprising lowering the partial pressure of water in the chlorodifluoromethane gas by contacting the chlorodifluoromethane gas with an aqueous solution of calcium chloride of more than 5% by weight.

Method for removing moisture from chlorodifluoro-methane

A process for producing chlorine by reaction of gaseous hydrogen chloride with oxygen in the presence of a catalyst prepared by reaction of chromium trioxide and cerous chloride with ethanol and calcination of the resulting reaction product, or, alternatively, prepared by reaction of chromium trioxide with ethanol, and calcination and impregnation of the resulting chromic oxide with aqueous solution of cerous chloride.

Cerous chloride-chromic oxide catalyst for producing chlorine, methods

A novel cerous chloride-chromium oxide catalyst useful for oxidizing hydrogen chloride to chlorine. The catalyst is prepared by the reaction of chromium trioxide and cerous chloride with ethanol and calcining the reaction product. The catalyst is also prepared by the reaction of chromium trioxide with ethanol, then calcination and impregnation of the resultant chromic oxide with aqueous solution of cerous chloride. The obtained catalyst exhibits high activity at low reaction temperature.

There are a catalyst for producing 1,1,1,2-tetrafluoroethane represented as Cr.sub.a L.sub.b M.sub.c O.sub.x F.sub.y wherein L is Mg or Ca; M is one element selected from a group consisting of Ce, Ni, Zn, and Al; and each value of a, b, c, x and y are all between 0 and 2, and a method for preparing the same comprising the steps of: producing an admixture of a composition comprising chromium hydroxide hydrate and magnesium chloride or calcium chloride in a weight ratio of Cr to Mg or Ca ranging from 1:0.3 to 1:10 with an aqueous metal salt solution; reacting the admixture with an aqueous HF solution to give a paste; and sintering the paste.

Catalyst for producing 1,1,1,2-tetrafluoroethane and method for

This specification discloses a process for preparing 1,1-dichlorofluoroethane (HCFC-141b) and 1-chloro-1,1-difluoroethane (HCFC-142b) from 1,1,1-trichloroethane and hydrogen fluoride which is capable of increasing reaction conversion and selectivity of the reaction products, HCFC-141b and HCFC-142b. According to the process of the invention, HCFC-142b, one of the reaction products, which has high solubility in both hydrogen fluoride and 1,1,1-trichloroethane, in the liquid phase reaction system is maintained at above 20 mole % relative to 1,1,1-trichloroethane. Therefore, the solubility of HF in the organic phase is remarkably enhanced, and the reaction of HF with 1,1,1-trichloroethane or vinylidene chloride is well promoted. Furthermore, the resident time of the reactant in the reaction vessel is shortened and thus the formation of tars is considerably prevented. According to the process of the invention, the hydrogen chloride produced during the fluorination is removed from the top of the reaction vessel, and the reaction mixture, except a minor portion of the lower boiling chlorofluorocarbons, are continuously recovered from the reactants in the bottom of the vessel, and then the desired products are separated from the reaction mixture with recycling the unreacted reactants and an effective amount of 1,1-difluoro-1-chloroethane into the vessel.

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Seoul, South Korea

Kun You Park