A method for improving preservation stability of 2,2-difluoroacetaldehyde according to the present invention include at least: a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system in which a 2,2-difluoroacetaldehyde hemiacetal coexists with an excess alcohol, wherein the total molar amount of the alcohol is 1.15 to 4.00 times the total molar amount of 2,2-difluoroacetaldehyde; and a second step of storing, in a storage container, the 2,2-difluoroacetaldehyde-alcohol composite system formed in the first step. It is possible by this method to suppress the conversion of the 2,2-difluoroacetaldehyde hemiacetal to a dimer and maintain the original aldehyde activity of the target compound with less composition change over a long term.

A method for improving preservation stability of 2,2-difluoroacetaldehyde according to the present invention include at least: a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system in which a 2,2-difluoroacetaldehyde hemiacetal coexists with an excess alcohol, wherein the total molar amount of the alcohol is 1.15 to 4.00 times the total molar amount of 2,2-difluoroacetaldehyde; and a second step of storing, in a storage container, the 2,2-difluoroacetaldehyde-alcohol composite system formed in the first step. It is possible by this method to suppress the conversion of the 2,2-difluoroacetaldehyde hemiacetal to a dimer and maintain the original aldehyde activity of the target compound with less composition change over a long term.

A method for improving preservation stability of 2,2-difluoroacetaldehyde according to the present invention include at least: a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system in which a 2,2-difluoroacetaldehyde hemiacetal coexists with an excess alcohol, wherein the total molar amount of the alcohol is 1.15 to 4.00 times the total molar amount of 2,2-difluoroacetaldehyde; and a second step of storing, in a storage container, the 2,2-difluoroacetaldehyde-alcohol composite system formed in the first step. It is possible by this method to suppress the conversion of the 2,2-difluoroacetaldehyde hemiacetal to a dimer and maintain the original aldehyde activity of the target compound with less composition change over a long term.

A method for improving preservation stability of 2,2-difluoroacetaldehyde according to the present invention include at least: a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system in which a 2,2-difluoroacetaldehyde hemiacetal coexists with an excess alcohol, wherein the total molar amount of the alcohol is 1.15 to 4.00 times the total molar amount of 2,2-difluoroacetaldehyde; and a second step of storing, in a storage container, the 2,2-difluoroacetaldehyde-alcohol composite system formed in the first step. It is possible by this method to suppress the conversion of the 2,2-difluoroacetaldehyde hemiacetal to a dimer and maintain the original aldehyde activity of the target compound with less composition change over a long term.

A method for improving preservation stability of 2,2-difluoroacetaldehyde according to the present invention include at least: a first step of forming a 2,2-difluoroacetaldehyde-alcohol composite system in which a 2,2-difluoroacetaldehyde hemiacetal coexists with an excess alcohol, wherein the total molar amount of the alcohol is 1.15 to 4.00 times the total molar amount of 2,2-difluoroacetaldehyde; and a second step of storing, in a storage container, the 2,2-difluoroacetaldehyde-alcohol composite system formed in the first step. It is possible by this method to suppress the conversion of the 2,2-difluoroacetaldehyde hemiacetal to a dimer and maintain the original aldehyde activity of the target compound with less composition change over a long term.

In one embodiment, the present invention provides a method, comprising: a. adding an effective amount of at least one compound selected from the group consisting of a substituted catechol, nitroxide free radicals, a compound of Formula 2, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, phenol, hydroxylamine, and phenylene diamine to a solution of a monomer selected from the group consisting of acrylonitrile, acrylic acid, vinylacetate, acrylates and acrolein; b. placing the monomer solution containing the at least one compound in a pressure vessel, pressurizing the pressure vessel and removing oxygen from the pressure vessel; and c. heating the monomer solution containing the at least one compound, wherein the at least one compound inhibits fouling by preventing polymerization of the monomer.

In one embodiment, the present invention provides a method, comprising: a. adding an effective amount of at least one compound selected from the group consisting of a substituted catechol, nitroxide free radicals, a compound of Formula 2, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, phenol, hydroxylamine, and phenylene diamine to a solution of a monomer selected from the group consisting of acrylonitrile, acrylic acid, vinylacetate, acrylates and acrolein; b. placing the monomer solution containing the at least one compound in a pressure vessel, pressurizing the pressure vessel and removing oxygen from the pressure vessel; and c. heating the monomer solution containing the at least one compound, wherein the at least one compound inhibits fouling by preventing polymerization of the monomer.

The coupling of aryl, heteroaryl, and vinyl halides with ,-difluoroketones or silyl ethers or siylenol ethers of ,-difluoroketones and ,-difluoroamides and esters are described. Further derivatization of the coupling products (such as ketone cleavage and Baeyer-Villiger oxidation) is also described.

The coupling of aryl, heteroaryl, and vinyl halides with ,-difluoroketones or silyl ethers or siylenol ethers of ,-difluoroketones and ,-difluoroamides and esters are described. Further derivatization of the coupling products (such as ketone cleavage and Baeyer-Villiger oxidation) is also described.

The invention provides a process for the preparation of xanthohumol, wherein a xanthohumol-containing extract is mixed with water, a transition metal salt solution is added to the obtained mixture, and then the obtained xanthohumol precipitate is collected and dried to obtain xanthohumol of the purity higher than 90%.