Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D.sub.2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.

Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D.sub.2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.

Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D.sub.2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.

Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to a first composition including one or more glycols and methanol under depolymerization conditions thereby providing one or more depolymerization products. The one or more depolymerization products can be exposed to an alcoholysis process to recover dialkyl terephthalate. Optionally, the one or more glycols and/or methanol can be recovered at the end of the alcoholysis process and re-used in subsequent processes for recovering dialkyl terephthalates.

Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to a first composition including one or more glycols and methanol under depolymerization conditions thereby providing one or more depolymerization products. The one or more depolymerization products can be exposed to an alcoholysis process to recover dialkyl terephthalate. Optionally, the one or more glycols and/or methanol can be recovered at the end of the alcoholysis process and re-used in subsequent processes for recovering dialkyl terephthalates.