The invention relates to a process for the preparation of acetals from carbon dioxide. The invention also relates to a mixture of phosphorus containing ligands comprising least one polydentate ligand and at least one monodentate ligand. Further, the invention also relates to the use of mixtures comprising at least one polydentate ligand and at least one monodentate ligand in transition metal complexes for the preparation of acetals.

The present invention relates to a process for preparing a haloalkyl alkoxymethyl ether compound (1B), wherein X.sup.1 represents a halogen atom, and R.sup.1 represents a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group, the process comprising the steps of converting a haloalkyl alkoxymethyl ether compound of the following general formula (1A), wherein X.sup.1 and R.sup.1 are as defined above, into a nucleophilic reagent, 4-alkoxymethoxy-1-methylbutyl, of the following general formula (2A), wherein M.sup.1A represents Li, MgZ.sup.1A, CuZ.sup.1A, or CuLiZ.sup.1A, Z.sup.1A represents a halogen atom or a 4-alkoxymethoxy-1-methylbutyl group, and R.sup.1 is as defined above, and subsequently subjecting the nucleophilic reagent, 4-alkoxymethoxy-1-methylbutyl (2A), to a nucleophilic addition reaction with propylene oxide of the following formula (3) to obtain 6-hydroxy-4-methylheptyl alkoxymethyl ether compound of the following general formula (4), wherein R.sup.1 is as defined above, and subjecting the 6-hydroxy-4-methylheptyl alkoxymethyl ether compound (4) to a halogenation reaction to form the aforesaid haloalkyl alkoxymethyl ether compound (1B).

##STR00001##

The present invention relates to a process for preparing a haloalkyl alkoxymethyl ether compound (1B), wherein X.sup.1 represents a halogen atom, and R.sup.1 represents a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group, the process comprising the steps of converting a haloalkyl alkoxymethyl ether compound of the following general formula (1A), wherein X.sup.1 and R.sup.1 are as defined above, into a nucleophilic reagent, 4-alkoxymethoxy-1-methylbutyl, of the following general formula (2A), wherein M.sup.1A represents Li, MgZ.sup.1A, CuZ.sup.1A, or CuLiZ.sup.1A, Z.sup.1A represents a halogen atom or a 4-alkoxymethoxy-1-methylbutyl group, and R.sup.1 is as defined above, and subsequently subjecting the nucleophilic reagent, 4-alkoxymethoxy-1-methylbutyl (2A), to a nucleophilic addition reaction with propylene oxide of the following formula (3) to obtain 6-hydroxy-4-methylheptyl alkoxymethyl ether compound of the following general formula (4), wherein R.sup.1 is as defined above, and subjecting the 6-hydroxy-4-methylheptyl alkoxymethyl ether compound (4) to a halogenation reaction to form the aforesaid haloalkyl alkoxymethyl ether compound (1B).

##STR00001##

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.

Provided are a terminal conjugated trienal acetal compound useful as an intermediate for producing a terminal conjugated trienal compound, and a method for producing a terminal conjugated trienal compound through deprotection of the terminal conjugated trienal acetal compound. More specifically, provided are a terminal conjugated trienal acetal compound represented by General Formula (1); a method for producing a (Z,E)-terminal conjugated trienal acetal compound, the method comprising the step of: reacting a phosphonium salt represented by General Formula (7) with (E)-2,4-pentadienal through Wittig reaction to obtain a (Z,E)-terminal conjugated trienal acetal compound represented by General Formula (3); and a method for producing a terminal conjugated trienal compound, the method comprising the step of: deprotecting the terminal conjugated trienal acetal compound represented by General Formula (1) to obtain a terminal conjugated trienal compound represented by General Formula (2). ##STR00001##

Provided are a terminal conjugated trienal acetal compound useful as an intermediate for producing a terminal conjugated trienal compound, and a method for producing a terminal conjugated trienal compound through deprotection of the terminal conjugated trienal acetal compound. More specifically, provided are a terminal conjugated trienal acetal compound represented by General Formula (1); a method for producing a (Z,E)-terminal conjugated trienal acetal compound, the method comprising the step of: reacting a phosphonium salt represented by General Formula (7) with (E)-2,4-pentadienal through Wittig reaction to obtain a (Z,E)-terminal conjugated trienal acetal compound represented by General Formula (3); and a method for producing a terminal conjugated trienal compound, the method comprising the step of: deprotecting the terminal conjugated trienal acetal compound represented by General Formula (1) to obtain a terminal conjugated trienal compound represented by General Formula (2). ##STR00001##

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.