This application is directed to use of transition metal-ligand complexes to hydrogenate fluorinated esters and carboxamides into fluorinated hemiacetals. Methods for synthesis of certain ligands are also provided.

A method of manufacturing a cetane-boosting fuel additive includes reacting formaldehyde and 2-ethylhexanol at a mole ratio of 10:1 to 1:1, or 5:1 to 1.5:1, or 4:1 to 2:1, or 3.5:1 to 2.5:1 in the presence of a heterogeneous acid catalyst at a temperature of 300 to 375 K to obtain a cetane-boosting product mixture comprising H.sub.3C(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3)CH.sub.2(OCH.sub.2).sub.nOH, H.sub.3C(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3)CH.sub.2(OCH.sub.2).sub.nOCH.sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3, or a combination thereof, wherein n has an average value of 2.8 to 3.2, preferably an average value of 3.

A method of manufacturing a cetane-boosting fuel additive includes reacting formaldehyde and 2-ethylhexanol at a mole ratio of 10:1 to 1:1, or 5:1 to 1.5:1, or 4:1 to 2:1, or 3.5:1 to 2.5:1 in the presence of a heterogeneous acid catalyst at a temperature of 300 to 375 K to obtain a cetane-boosting product mixture comprising H.sub.3C(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3)CH.sub.2(OCH.sub.2).sub.nOH, H.sub.3C(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3)CH.sub.2(OCH.sub.2).sub.nOCH.sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3, or a combination thereof, wherein n has an average value of 2.8 to 3.2, preferably an average value of 3.

Disclosed is an industrial method for efficient production of an ,-difluoroaldehyde compound, which includes reaction of an ,-difluoroacetate with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst and a base. By the adoption of specific reaction conditions (catalyst, base, pressure etc.), it is possible to produce the target ,-difluoroaldehyde compound with a high conversion rate and high selectivity.

Disclosed is an industrial method for efficient production of an ,-difluoroaldehyde compound, which includes reaction of an ,-difluoroacetate with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst and a base. By the adoption of specific reaction conditions (catalyst, base, pressure etc.), it is possible to produce the target ,-difluoroaldehyde compound with a high conversion rate and high selectivity.

Disclosed is an industrial method for efficient production of an ,-difluoroaldehyde compound, which includes reaction of an ,-difluoroacetate with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst and a base. By the adoption of specific reaction conditions (catalyst, base, pressure etc.), it is possible to produce the target ,-difluoroaldehyde compound with a high conversion rate and high selectivity.

Disclosed is an industrial method for efficient production of an ,-difluoroaldehyde compound, which includes reaction of an ,-difluoroacetate with hydrogen gas (H.sub.2) in the presence of a ruthenium catalyst and a base. By the adoption of specific reaction conditions (catalyst, base, pressure etc.), it is possible to produce the target ,-difluoroaldehyde compound with a high conversion rate and high selectivity.

Disclosed is a method for preserving an ,-difluoroacetaldehyde alkyl hemiacetal of the following formula in a gas-liquid state having gas and liquid phases in a closed container under an atmosphere of oxygen (O.sub.2) or inert gas, characterized by: controlling the oxygen concentration of the gas phase in the container to be 5000 ppm or lower; and then storing the ,-difluoroacetaldehyde alkyl hemiacetal in the container under light-shielding conditions

##STR00001##

where R.sup.1 represents an alkyl group or a substituted alkyl group.

It is possible by this method to suppress conversion of the ,-difluoroacetaldehyde alkyl hemiacetal to difluoroacetic acid over a long term.

Disclosed is a method for preserving an ,-difluoroacetaldehyde alkyl hemiacetal of the following formula in a gas-liquid state having gas and liquid phases in a closed container under an atmosphere of oxygen (O.sub.2) or inert gas, characterized by: controlling the oxygen concentration of the gas phase in the container to be 5000 ppm or lower; and then storing the ,-difluoroacetaldehyde alkyl hemiacetal in the container under light-shielding conditions

##STR00001##

where R.sup.1 represents an alkyl group or a substituted alkyl group.

It is possible by this method to suppress conversion of the ,-difluoroacetaldehyde alkyl hemiacetal to difluoroacetic acid over a long term.

Disclosed is a method for preserving an ,-difluoroacetaldehyde alkyl hemiacetal of the following formula in a gas-liquid state having gas and liquid phases in a closed container under an atmosphere of oxygen (O.sub.2) or inert gas, characterized by: controlling the oxygen concentration of the gas phase in the container to be 5000 ppm or lower; and then storing the ,-difluoroacetaldehyde alkyl hemiacetal in the container under light-shielding conditions

##STR00001##

where R.sup.1 represents an alkyl group or a substituted alkyl group.

It is possible by this method to suppress conversion of the ,-difluoroacetaldehyde alkyl hemiacetal to difluoroacetic acid over a long term.