An object of the present invention is to provide a method for stabilizing an acrylic acid derivative, and a composition containing an acrylic acid derivative in which the acrylic acid derivative is stabilized. The present invention provides a composition comprising: (A) an acrylic acid derivative represented by Formula (I):

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(wherein, R.sup.1 and R.sup.2 are the same or different, and each represents alkyl, fluoroalkyl, aryl that may have one or more substituents, halogen, or hydrogen; R.sup.c represents a group: OR.sup.3 (wherein R.sup.3 represents alkyl, fluoroalkyl, aryl that may have one or more substituents, or hydrogen) or halogen; and X represents fluoroalkyl, alkyl, hydrogen, or halogen); and (B) amide, wherein the content of acrylic acid derivative (A) is 30% (w/w) or more.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.

Disclosed herein are acid addition salt and salt crystals of (6aR, 9aS)-5,6a,7,8,9,9a-hexahydro-5-methyl-3-(phenylamino)-2-((4(6-fluoropyridin-2-yl)phenyl)methyl)-cyclopent[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one, compositions comprising the same as well as methods of making and using such salts and crystals.

Disclosed herein are acid addition salt and salt crystals of (6aR, 9aS)-5,6a,7,8,9,9a-hexahydro-5-methyl-3-(phenylamino)-2-((4(6-fluoropyridin-2-yl)phenyl)methyl)-cyclopent[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one, compositions comprising the same as well as methods of making and using such salts and crystals.

An object is to prevent lowering in the yield of RCOF due to contamination by impurities and thereby to produce a high-purity product of RCOF in a stable manner. According to the present invention, provided are: a method of purifying a carboxylic acid fluoride, comprising a step of removing a hydrogen halide by bringing a carboxylic acid fluoride containing the hydrogen halide into contact with a metal fluoride; a method of producing a high-purity carboxylic acid fluoride, comprising a step of bringing a carboxylic acid fluoride containing a hydrogen halide into contact with a metal fluoride as well as a high-purity carboxylic acid fluoride obtained therefrom; and a method of using a metal fluoride as an adsorbent for a hydrogen halide in a method of removing a hydrogen halide from a carboxylic acid fluoride containing the hydrogen halide.