A compound of formula I,

##STR00001##

Further, a method of production of a compound of formula I, the use of said compounds in LC media, and LC media comprising one or more compounds of formula I. Further, a method of production of such LC media, the use of such media in LC devices, and a LC device comprising a LC medium according to the present invention. Also, a process for the fabrication of such a liquid crystal display and the use of the liquid crystal mixtures according to the invention for the fabrication of such a liquid crystal display.

A compound of formula I,

##STR00001##

Further, a method of production of a compound of formula I, the use of said compounds in LC media, and LC media comprising one or more compounds of formula I. Further, a method of production of such LC media, the use of such media in LC devices, and a LC device comprising a LC medium according to the present invention. Also, a process for the fabrication of such a liquid crystal display and the use of the liquid crystal mixtures according to the invention for the fabrication of such a liquid crystal display.

The present invention is directed to a purification method for purifying a fluorine-containing polymerizable monomer of the formula (1), in which the fluorine-containing polymerizable monomer is purified by distillation in the coexistence of a phenolic compound A such as 6-tert-butyl-2,4-xylenol and a phenolic compound B such as 2,2′-methylene-bis(4-methyl-6-tert-butylphenol).

##STR00001##

By the combined use of the phenolic compound A and the phenolic compound B, it is possible to significantly suppress polymerization or oligomerization of the fluorine-containing polymerizable monomer even during industrial-production-scale distillation and efficiently purify the fluorine-containing polymerizable monomer by distillation.

The present invention is directed to a purification method for purifying a fluorine-containing polymerizable monomer of the formula (1), in which the fluorine-containing polymerizable monomer is purified by distillation in the coexistence of a phenolic compound A such as 6-tert-butyl-2,4-xylenol and a phenolic compound B such as 2,2′-methylene-bis(4-methyl-6-tert-butylphenol).

##STR00001##

By the combined use of the phenolic compound A and the phenolic compound B, it is possible to significantly suppress polymerization or oligomerization of the fluorine-containing polymerizable monomer even during industrial-production-scale distillation and efficiently purify the fluorine-containing polymerizable monomer by distillation.

Provided is an additive for an optical resin including a (meth)acrylate compound represented by general formula (1) below: ##STR00001##
[in general formula (1), each X independently represents a fluorine atom or a methyl group in which at least one hydrogen atom is substituted with a fluorine atom; m represents an integer of 0 to 5; R.sup.1 represents an alkylene group or an oxyalkylene group having a carbon number of 1 to 8; and R.sup.2 represents a hydrogen atom or a methyl group].

The present invention relates to novel compounds containing fluorinated end groups and to the use thereof in, for example, dirt-repellent coatings.

The present invention relates to novel compounds containing fluorinated end groups and to the use thereof in, for example, dirt-repellent coatings.

An object of the present invention is to provide a novel method for producing an α-fluoroacrylic acid ester compound.

##STR00001##

This problem is solved by a method for producing a compound represented by formula (1), wherein R.sup.1 and R.sup.2 are identical or different, and each represents an alkyl group or the like; and R.sup.3 is an alkyl group or the like, the method comprising step A of reacting a compound represented by formula (2) with R.sup.3—OH (3) and carbon monoxide in the presence of palladium, a double bond-containing compound (α), a diphosphine compound (β), and a base, to obtain the compound represented by formula (1) above.

An object of the present invention is to provide a novel method for producing an α-fluoroacrylic acid ester compound.

##STR00001##

This problem is solved by a method for producing a compound represented by formula (1), wherein R.sup.1 and R.sup.2 are identical or different, and each represents an alkyl group or the like; and R.sup.3 is an alkyl group or the like, the method comprising step A of reacting a compound represented by formula (2) with R.sup.3—OH (3) and carbon monoxide in the presence of palladium, a double bond-containing compound (α), a diphosphine compound (β), and a base, to obtain the compound represented by formula (1) above.

A (meth)acrylate compound excellent in compatibility with other photosensitive resins and capable of providing a polymer with high transparency, a polymer, a resist material, and a method for producing the (meth)acrylate compound. The (meth)acrylate compound is represented by formula (1). ##STR00001##