Abstract: A polycarbonate copolymer which comprises 30 to 70 mol % of a structural unit comprising a bisphenyl fluorene structure and 70 to 30 mol % of a structural unit comprising tricyclo [5.2.1.02.6] decanedimethanol and causes little occurrence of a birefringence even when extrusion, injection molding or stretch processing is conducted and a process for producing the same.

Abstract: A polycarbonate copolymer which comprises 30 to 70 mol % of a structural unit comprising a bisphenyl fluorene structure and 70 to 30 mol % of a structural unit comprising tricyclo [5.2.1.02,6] decanedimethanol and causes little occurrence of birefringence even when extrusion, injection molding or stretch processing is conducted and a process for producing the same.

Abstract: An acid anhydride of the formula (4), and a polyimide using the acid anhydride, 1

Abstract: A process for producing a polycarbonate resin which comprises performing melt polycondensation of pentacyclopentadecanedimethanol or pentacyclopentadecanedimethanol and diol with carbonic acid diester in the presence of a catalyst containing at least one compound selected from the group consisting of zinc compounds, tin compounds, lead compounds, zirconium compounds and hafnium compounds.

Abstract: An object of the present invention is to carry out separation recovery of ammonia efficiently from a gaseous mixture containing ammonia and carbon dioxide, without generating a solid ammonium carbamate. A recovery method of ammonia from a gaseous mixture, includes a process (I) in which a gaseous mixture containing ammonia and carbon dioxide is contacted with an organic solvent to allow the organic solvent to absorb ammonia in the gaseous mixture, and a process (II) in which the organic solvent which absorbed ammonia is distilled to separate ammonia from the organic solvent.

Abstract: A process for producing a polycarbonate resin which comprises performing melt polycondensation of pentacyclopentadecanedimethanol or pentacyclopentadecanedimethanol and diol with carbonic acid diester in the presence of a catalyst containing at least one compound selected from the group consisting of zinc compounds, tin compounds, lead compounds, zirconium compounds and hafnium compounds.

Abstract: A process for producing a dialkyl carbonate which comprises performing reaction of allophanate represented by the following general formula (1) and an alkyl alcohol represented by the following general formula (2) as raw materials, thereby producing a dialkyl carbonate represented by the following general formula (3). RO—CO—NH—CO—NH2   (1) ROH  (2) RO—CO—OR  (3) wherein R is an alkyl group.

Abstract: An object of the present invention is to carry out separation recovery of ammonia efficiently from a gaseous mixture containing ammonia and carbon dioxide, without generating a solid ammonium carbamate. A recovery method of ammonia from a gaseous mixture, includes a process (I) in which a gaseous mixture containing ammonia and carbon dioxide is contacted with an organic solvent to allow the organic solvent to absorb ammonia in the gaseous mixture, and a process (II) in which the organic solvent which absorbed ammonia is distilled to separate ammonia from the organic solvent.

Abstract: A process for producing a dialkyl carbonate which comprises performing reaction of allophanate represented by the following general formula (1) and an alkyl alcohol represented by the following general formula (2) as raw materials, thereby producing a dialkyl carbonate represented by the following general formula (3).

Abstract: A process for separation between dialkyl carbonate and alkyl carbamate which comprises adding an aromatic hydroxy compound to a liquid comprising alkyl carbamate having an alkyl group having 3 to 6 carbon atoms and dialkyl carbonate having alkyl group having 3 to 6 carbon atoms to obtain a mixed liquid, and distilling the mixed liquid thus obtained in a distillation column to obtain a mixture comprising the dialkyl carbonate and the aromatic hydroxy compound from a top section of the distillation column and a liquid comprising the alkyl carbamate from a bottom section of the distillation column.

Abstract: A process for producing a dialkyl carbonate which comprises reacting at least one member selected from the group consisting of urea and alkyl carbamate with alcohol in the presence of both a catalyst and a high boiling point organic compound having a boiling point of 180.degree. C. or above.

Abstract: A process for producing diaryl carbonate which comprises (A) a step for producing dialkyl carbonate represented by the general formula RO--CO--OR by reacting urea with alkyl alcohol represented by the general formula ROH, (B) a step for producing both alkyl aryl carbonate represented by the general formula RO--CO--OAr and diaryl carbonate represented by the general formula ArO--CO--OAr by reacting dialkyl carbonate produced in the above step (A) with an aromatic hydroxy compound represented by the general formula ArOH, and (C) a step for producing diaryl carbonate represented by the general formula ArO--CO--OAr by allowing to conduct disproportionation reaction of unreacted alkyl aryl carbonate produced in the above step (B), wherein R shows an alkyl group and Ar shows a non-substituted phenyl group or a phenyl group substituted by alkyl group, alkoxy group, aryl group, aryloxy group or halogen.

Abstract: A process for producing an aromatic carbonate which comprises: reacting a dialkyl carbonate represented by general formula (1) with an aromatic carboxylic acid aryl ester represented by general formula (2) in the presence of a catalyst to produce an aromatic carbonate represented by one or both of general formulae (3) and (4):R--OCOO--R (1)Ar'--COO--Ar (2)Ar--OCOO--R (3)Ar--OCOO--Ar (4)wherein R represents an alkyl group having from 1 to 4 carbon atoms, and Ar and Ar' each represents an unsubstituted phenyl group or a phenyl group substituted by a substituent selected from the group consisting of alkyl, alkoxy, aryl, aryloxy and a halogen atom.

Abstract: Anti-ferroelectric liquid crystal substances which are represented by the formula (1): ##STR1## wherein R is a straight chain alkyl group having 6 to 10 carbon atoms,X is hydrogen or fluorine atom,Z is --CH.sub.3, --CF.sub.3 or --C.sub.2 H.sub.5, andC** stands for an asymmetric carbon atom, andl, m, and n are 0 or a certain integer depending on the specific kinds of X and Z,and the use of the substances for liquid crystal display devices.

Abstract: A process for producing an aromatic carbonate which comprises:reacting(a) an aromatic hydroxy compound with(b) carbon monoxide in the presence of(c) an oxidation agent,(d) a catalyst comprising a palladium compound or impregnated palladium catalyst,(e) a co-catalyst comprising a manganese compound, a cobalt compound or a copper compound, and(f) at least one nitrile compoundat a temperature of 20.degree. to 300.degree. C.

Abstract: A liquid crystal compound represented by formula (I), ##STR1## wherein A represents --C.sub.3 H.sub.7, --C.sub.4 H.sub.9 or --C.sub.8 H.sub.17 ; when A is --C.sub.3 H.sub.7, m is an integer of 8, 10, 12 or 14; and when A is --C.sub.4 H.sub.9 or --C.sub.8 H.sub.17, m is an integer of 7 to 14,said compound having an antiferroelectric phase.

Abstract: An antiferroelectric liquid crystal compound which is a compound represented by ##STR1## wherein R denotes a linear aliphatic alkyl group having 6 to 14 carbon atoms; A denotes a single bond or an oxygen atom; X and Y independently denote a hydrogen atom or a fluorine atom but they are not hydrogen atoms at the same time; h and i are independently 1 or 2; m is an integer of 3 to 10; Z denotes CH.sub.3, C.sub.2 H.sub.5 or CF.sub.3 ; k is 0 or an integer of 5 to 8; l is 0 or 1; n is an integer of 1 to 6; W denotes CH.sub.3 or CF.sub.3 ; when W is CH.sub.3, p and q are both 0 and r is 8; when W is CF.sub.3, p is 5 to 8, q is 1 and r is 1 to 4; and C* denotes an asymmetric carbon atom,and a liquid crystal display device using same.

Abstract: A process for producing a sulfonium compound of the formula (III) ##STR1## which process comprises reacting a p-dialkylsulfoniophenol of the formula (I) ##STR2## and a carbonyl halogenide compound of the formula (II) ##STR3## in the presence of a secondary amine having a structure in which two secondary alkyl groups are linked to the nitrogen atom, wherein R.sup.1 and R.sup.2 are the same or different and are independently an alkyl group having 1 to 4 carbon atoms, X.sup.1 is a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, Y.sup.- is a halogen anion, a perchlorate anion, an alkylsulfate anion, a hydrogensulfate anion or a p-toluenesulfonate anion, R is an alkyl group having 1 to 20 carbon atoms, a tert-butoxy group, a benzyloxy group, a p-methoxybenzyloxy group, a phenyl group or a 9-fluorenylmethoxy group, and X.sup.

Abstract: Contact lenses are treated with hydrogen peroxide and the remaining hydrogen peroxide is decomposed by electrolysis.

Abstract: A membrane for gas separation which comprises a silylated polyphenylene ether is disclosed. Said silylated polyphenylene ether contains a constituting unit containing an organosilane or siloxane group represented by the following formula in at least a part of the repeating unit thereof: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents a hydrogen atom or a group of the formula --Si(R.sub.5)(R.sub.6)(R.sub.7), wherein R.sub.5, R.sub.6 and R.sub.7 each represents an alkyl group; l and n each represents 0 or an integer from 1 to 3; and m represent an integer of from 1 to 3; with the proviso that R.sub.1, R.sub.2, R.sub.3 and R.sub.4 do not simultaneously represent hydrogen atoms.