Korea Institute of Science and Technology

Samsung Electronics Co., Ltd.

Goldstar, Co., Ltd.

Young Soo Kwon

Hoon Sik Kim

Moon Jo Chung

Byung Gwon Lee

Kun You Park

Byoung Sung Ahn

Dong Ju Moon

Hong Gon Kim

Honggon Kim

Chang Tae Kim

Hyun Joo Lee

Sang Deuk Lee

Jong Sung Lim

Seung H Ahn

Jai Jun Kim

Sang-deuk Lee

Jin Hee Shin

Kun Yu Park

Dong Joo Mun

Method of a simultaneous preparation of hexafluoropropylene and octafluorocyclobutane

The present invention relates to a process for preparing hexafluoropropylene(CF CF&boxH;CF , HFP) from the pyrolysis of trifluoromethane(CHF , R23) and tetrafluoroethylene(C F , TFE) and more particularly, to the process for preparing hexafluoropropylene from the pyrolysis of an admixture of R23 and TFE mixed in an appropriate molar ratio at below 900 which is lower than the conventional reaction temperature and longer residence time, after investigating the pyrolysis reaction of R23 and TFE by the computer simulation. The process for preparing HFP is performed by carefully controlling reaction temperature with heat balance resulted from an endothermic pyrolysis of R23 and an exothermic dimerization of TFE to prevent from carbon formation, recycling unreacted R23 and TFE in the product separated and purified from distillation column, adding fresh R23 additionally to keep an appropriate molar ratio of R23 and TFE, to improve a total yield of HFP and to minimize heat supply from outside.

Preparation of hexafluoropropylene from the pyrolysis of trifluoromethane and tetrafluoroethylene

High performance catalyst systems for the synthesis of alkylenecarbonates

A refrigerant composition useful as a substitute for chlorodifluoromethane (CHClF,, HCFC-22). The refrigerant composition has a first constituent of difluoromethane (CH,F,, HFC-32); a second constituent of 1,1,1-trifluoroethane (CH,CF,; namely, HFC-143a); and a third constituent selected from 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), 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 difluoromethane and 1,1,1-trifluoroethane

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

Preparation of alkylene carbonate using manganese halides as catalyst

This invention relates to a method for preparing cycloaliphatic diamines by hydrogenating aromatic diamines in the presence of a supported ruthenium catalyst and a metal nitrite as a catalyst promoter to increase the rate of the hydrogenation reaction and decrease the amount of higher boiler by-products.

Method for preparing cycloaliphatic diamines from aromatic diamines

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 semiconductor device having at least one semiconductor chip loaded on a lower surface of a printed circuit board, electrode terminals of the semiconductor chip wire-bonded to terminals on the printed circuit board, and a connection portion of the semiconductor chip and wires encapsulated by means of encapsulating resin includes a semiconductor device of three-dimensional structure having the printed circuit board reversely mounted, the terminals of the printed circuit board connected to external terminals via through holes, and at least one semiconductor device stacked on an upper surface of the printed circuit board, thereby interconnecting respective semiconductor devices while interposing solder balls to be mounted to other printed circuit boards by leads being the external terminals. Thus, a ball grid array (BGA) package able to be stacked inside a small out-line J-lead (SOJ) package is used for performing interconnection to make the BGA overcome a typically two-dimensional flat mounting and attain a three-dimensional surface mounting structure while being perfectly compatible with a currently-available mounting process on the main substrate, thereby improving mounting efficiency.

J-leaded semiconductor package having a plurality of stacked ball grid

A method of making a FET includes the steps of forming a source and a drain at respective edges of the surface of a semiconductor substrate, forming a first insulation film on the whole surfaces of the semiconductor substrate, the source, and the drain, coating a photoresist on the first insulation film, patterning the photoresist using a photolithography process to form a photoresist pattern having a first space corresponding to a gate length between the source and the drain, forming a second insulating film on the whole surfaces of the exposed first insulation film and the photoresist pattern, etching the second insulation film to form sidewall insulation films at the sidewalls of the photoresist patterns, etching the first insulation film using the sidewall insulation films and the photoresist pattern as an etching mask to form first insulation film patterns, which form a second space having a width smaller than that of the first space, beneath the first space, removing the sidewall insulation films to form a T-shaped space, and depositing a conductor to form a T-shaped gate in the T-shaped space.

Method of making a field effect transistor

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.

Process for preparing dichlorofluoroethane and chlorodifluoroethane

A field effect transistor is disclosed in which a source region and a drain region are formed to be reverse mesa on a semi-insulating semiconductor substrate with an insulating layer thereon by using a crystal growth characteristic corresponding to the crystal orientation. A channel layer and a gate electrode are formed by self-alignment on the upper part of a void formed according to the reverse mesa of the source and the drain regions, so that the channel layer and the semiconductor substrate are electrically separated by the void. By such a construction, a leakage current and backgating effect are removed, and a fast field effect transistor is attained owing to the reduction of an effective channel length and a gate resistance.

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Seoul, South Korea

Young Soo Kwon