摘要:
An optically active block polyester copolymer formed of structural units represented by the following general formulas (I) and (II): ##STR1## wherein represents for an asymmetric carbon atom and m and n each represents a natural number in the range of from 300 to 5000 is obtained by subjecting an optically active butyrolactone and a species of lactone other than the optically active butyrolactone to sequential ringopening copolymerization in the presence of a catalyst. This optically active block polyester copolymer possesses a high molecular weight and a high melting point (not less than 130.degree. C.) and forms a biodegradable and hydrolyzable material of high strength capable of tolerating the impacts of actual use.
摘要:
The biodegradable composition comprises at least poly(beta-hydroxybutyric acid) or a biodegradable copolymer thereof and a stereospecifically regular block copolymer having the structure units of formula (I): ##STR1## where R1 is a hydrocarbon group having 1 to 14 carbon atoms, optionally including double bonds, oxygen atoms or both of them; and m and n are respectively an integer ranging from 300 to 5,000, or having the structure units of formula (II): ##STR2## where R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are either a hydrogen atom or a methyl group; and m and n are respectively an integer ranging from 300 to 5,000.
摘要:
The block copolymer of polyesters and polycarbonates comprises at least one of each of the constituting units of (I) and (II) having the general formulae: ##STR1## where the sign * indicates an asymmetric carbon atom; R.sub.1, R.sup.2, R.sup.3 and R.sup.4 are either a hydrogen atom or a methyl group; m and n are respective a natural numbers ranging from 300 to 5000: The block copolymer is obtained by successive ring-opening and copolymerization of optically active .beta.-butyrolactones and cyclic carbonates in the presence of a catalyst.The block polymer obtained has high molecular weight and high melting temperature, and can thus be used as a high strength material for practical use and which has bio-degradable and hydrolyzable nature.
摘要:
A novel phosphine compound usable as a catalyst in various asymmetric synthetic reactions is disclosed. The compound is a 2,2'-bis(diarylphosphino)-6,6'-bis(trifluoromethyl)-1,1'-biphenyl of (1): ##STR1## where R is a phenyl group or a phenyl group substituted by lower alkyl group, lower alkoxy group, halogen atom, or lower haloalkyl group.
摘要:
An optically active oligomer obtained by polycondensation of an (R)-3-hydroxyalkanoic acid alkyl ester and at least one of a diol, a diamine and an amino alcohol and an optically active polymer obtained by copolymerization of said oligomer and a monomer selected from diisocyanic acid esters, dicarboxylic acid derivatives, and dichlorosilanes are disclosed. Novel functional polymers with biodegradability and hydrolyzability are produced with industrial advantage.
摘要:
An optically active compound which itself generally exhibits no antiferroelectric liquid crystal phase, but which can be added to an antiferroelectric liquid crystal or composition thereof having a high threshold voltage to reduce the threshold voltage of the resulting composition. Also disclosed is an antiferroelectric liquid crystal composition containing the optically active compound, a process for reducing the threshold voltage of an antiferroelectric liquid crystal composition, a process for producing the optically active compound, and a process for producing an optically active carboxylic acid as an intermediate.
摘要:
A fluorine-containing optically active compound represented by formula (I): ##STR1## wherein R.sub.1 represents a straight chain alkyl or alkoxy group having from 6 to 14 carbon atoms or a 4-alkylphenyl or 4-alkoxyphenyl group having from 8 to 12 carbon atoms; R.sub.2 represents a straight chain alkyl group having from 1 to 8 carbon atoms; C.sup.* represents an asymmetric carbon atoms; and X represents a hydrogen atom or a fluorine atom, provided that X represents a fluorine atom when R.sub.1 contains a phenyl group, and a liquid crystal composition containing the same are disclosed. The compound (I) has large spontaneous polarization and low viscosity to achieve a fast response time. In the N.sup.* phase of the compound (I), the helical pitch has small temperature dependence.
摘要翻译:由式(I)表示的含氟光学活性化合物:(*化学结构*)(I)其中R1表示具有6至14个碳原子的直链烷基或烷氧基或4-烷基苯基或4-烷氧基苯基 具有8至12个碳原子; R 2表示具有1至8个碳原子的直链烷基; C *表示不对称碳原子; 并且X表示氢原子或氟原子,条件是当R 1包含苯基时,X表示氟原子,并且公开了含有该基团的液晶组合物。 化合物(I)具有大的自发极化和低粘度以实现快速响应时间。 在化合物(I)的N *相中,螺旋间距具有较小的温度依赖性。
摘要:
Disclosed is a novel optically active compound which exhibits an antiferroelectric liquid crystal phase and has a low threshold voltage and a low viscosity, a novel optically active compound which doesn't exhibit an antiferroelectric liquid crystal phase but can be incorporated in an antiferroelectric liquid crystal having a high threshold voltage to reduce the threshold voltage thereof, an antiferroelectric liquid crystal composition containing the compound, and a process for the reduction of the threshold voltage of an antiferroelectric liquid crystal composition.
摘要:
An optically active 7-substituted-1,4-dioxepan-5-one derivative represented by the general formula (I): ##STR1## wherein R represents an alkyl group having from 1 to 5 carbon atoms; and * means an asymmetric carbon atom, is disclosed. An optically active polymer represented by formula (II): ##STR2## wherein R and * are as defined above; and n is an integer of 25 or more, obtained by ring opening polymerization of the optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) is also disclosed. A process for producing the optically active polymer represented by formula (II) is further disclosed, comprising subjecting an optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) to ring opening polymerization in the presence of at least one catalyst selected from the group consisting of (i) an organotin compound, (ii) an organoaluminum compound and water, and (iii) an organozinc compound and water.
摘要:
A biodegradable, optically active copolymer is disclosed. The copolymer is represented by general formula (I): ##STR1## wherein R.sup.1 represents a group selected from the group consisting of methyldimethylene, 1,2-dimethyldimethylene, 1,1-dimethyldimethylene, methyltrimethylene, tetramethylene, methyltetramethylene, pentamethylene, 1,4-dimethyl-2-oxo-3-oxytetramethylene, 2-oxo-3-oxytetramethylene, and 2-methyl-3-oxypentamethylene, and m and n each represents a natural number of from 10 to 15,000. According to the present invention, useful polymers which are a new type of functional materials characterized as having optical activity, biodegradability (enzymatic degradability), and hydrolyzability can be easily produced in an industrially advantageous manner by the ring-opening copolymerization of optically active .beta.-butyrolactone with various lactones.