The presently claimed invention relates to a process for purification of aroma compounds by distillation. Specifically, it relates to a process for purification of carbonic esters of formula (I) using a combination of distillative processes.

The presently claimed invention relates to a process for purification of aroma compounds by distillation. Specifically, it relates to a process for purification of carbonic esters of formula (I) using a combination of distillative processes.

The present invention relates to a process for preparing an organic carbonate, comprising contacting carbon dioxide with an alcohol in the presence of water and a catalyst in a reaction zone resulting in the production of the organic carbonate, wherein the organic carbonate is continuously removed from the reaction zone.

The present invention relates to a process for preparing an organic carbonate, comprising contacting carbon dioxide with an alcohol in the presence of water and a catalyst in a reaction zone resulting in the production of the organic carbonate, wherein the organic carbonate is continuously removed from the reaction zone.

Disclosed are a diaryl carbonate containing a compound of the following formula (I) in an amount of less than 1,000 ppm by mass, and a method for producing the same: ##STR00001## wherein R.sup.l represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group. Disclosed methods include reacting urea with an alkyl alcohol to provide a dialkyl carbonate; reacting the dialkyl carbonate with an aryl alcohol to provide an alkylaryl carbonate; subjecting the alkylaryl carbonate to disproportionation to yield a mixture comprising a diaryl carbonate; and purifying the mixture.

Disclosed are a diaryl carbonate containing a compound of the following formula (I) in an amount of less than 1,000 ppm by mass, and a method for producing the same: ##STR00001## wherein R.sup.l represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group. Disclosed methods include reacting urea with an alkyl alcohol to provide a dialkyl carbonate; reacting the dialkyl carbonate with an aryl alcohol to provide an alkylaryl carbonate; subjecting the alkylaryl carbonate to disproportionation to yield a mixture comprising a diaryl carbonate; and purifying the mixture.

Disclosed are a diaryl carbonate containing a compound of the following formula (I) in an amount of less than 1,000 ppm by mass, and a method for producing the same: ##STR00001## wherein R.sup.l represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group. Disclosed methods include reacting urea with an alkyl alcohol to provide a dialkyl carbonate; reacting the dialkyl carbonate with an aryl alcohol to provide an alkylaryl carbonate; subjecting the alkylaryl carbonate to disproportionation to yield a mixture comprising a diaryl carbonate; and purifying the mixture.

The present disclosure relates to spirobiindane derivatives and a process for preparation of the same. Spirobiindane derivatives are used as intermediates for many commercially important compounds such as chiral polymers. The present disclosure provides a simple and economical process for the preparation of spirobiindane derivatives of Formula (I) with high yield and having high purity.

##STR00001##

The present disclosure relates to spirobiindane derivatives and a process for preparation of the same. Spirobiindane derivatives are used as intermediates for many commercially important compounds such as chiral polymers. The present disclosure provides a simple and economical process for the preparation of spirobiindane derivatives of Formula (I) with high yield and having high purity.

##STR00001##

A process for the work-up of salt-containing process water which contains an alkali metal chloride as salt in a concentration of at least 4% by weight and organic or inorganic and organic impurities from chemical production processes and reuse of the salt by a combination of prepurification and concentration, crystallization and purification of the salt and optionally subsequently use of the salt in an electrolysis for producing basic chemicals are described.