Embodiments of the present invention are directed to processes for the production of (R)-3-hydroxybutyl (R)-3-hydroxybyrate. Poly (R)-3-hydroxybyrate is transesterified with an alcohol, to form a first ester portion and a second ester portion. The first ester portion is reduced to the diol to form a diol portion and the diol portion is reacted with the second ester portion to produce (R)-3-hydroxybutyl (R)-3-hydroxybyrate.

Embodiments of the present invention are directed to processes for the production of (R)-3-hydroxybutyl (R)-3-hydroxybyrate. Poly (R)-3-hydroxybyrate is transesterified with an alcohol, to form a first ester portion and a second ester portion. The first ester portion is reduced to the diol to form a diol portion and the diol portion is reacted with the second ester portion to produce (R)-3-hydroxybutyl (R)-3-hydroxybyrate.

The present invention relates to a process for depolymerizing a polyester feedstock comprising opaque PET, which comprises: a) a conditioning step; b) a step of glycolysis, operated at between 180 and 400° C., a residence time of from 0.1 to 10 h in the presence of diol; c) a diol separation step, at a temperature of between 100 and 250° C., a pressure lower than that of step b) and producing a diol effluent and an effluent rich in monomers; d) a step of separating into a heavy impurities effluent and a prepurified monomers effluent, at a temperature of less than 250° C. and a pressure of less than 0.001 MPa and a residence time of less than 10 min; e) a step of decolourizing the prepurified monomers effluent, by adsorption of a mixture comprising between 20% and 90% by weight of the prepurified monomers effluent and a solvent, at a temperature of between 100 and 200° C., a pressure of between 0.1 and 1.0 MPa and in the presence of at least one adsorbent.

The present invention relates to a process for depolymerizing a polyester feedstock comprising opaque PET, which comprises: a) a conditioning step; b) a step of glycolysis, operated at between 180 and 400° C., a residence time of from 0.1 to 10 h in the presence of diol; c) a diol separation step, at a temperature of between 100 and 250° C., a pressure lower than that of step b) and producing a diol effluent and an effluent rich in monomers; d) a step of separating into a heavy impurities effluent and a prepurified monomers effluent, at a temperature of less than 250° C. and a pressure of less than 0.001 MPa and a residence time of less than 10 min; e) a step of decolourizing the prepurified monomers effluent, by adsorption of a mixture comprising between 20% and 90% by weight of the prepurified monomers effluent and a solvent, at a temperature of between 100 and 200° C., a pressure of between 0.1 and 1.0 MPa and in the presence of at least one adsorbent.

Methods and systems for producing alkyl hydroxyalkanoates from hydroxycarboxylic acid recovery bottoms. The methods generally comprise the steps of obtaining a hydroxycarboxylic acid recovery bottom, adding a mono-alcohol to the hydroxycarboxylic acid recovery bottom to obtain a first mixture, heating the first mixture, optionally in the presence of a catalyst to form a reaction product, distilling the reaction product, and recovering an alkyl hydroxyalkanoate fraction.

Methods and systems for producing alkyl hydroxyalkanoates from hydroxycarboxylic acid recovery bottoms. The methods generally comprise the steps of obtaining a hydroxycarboxylic acid recovery bottom, adding a mono-alcohol to the hydroxycarboxylic acid recovery bottom to obtain a first mixture, heating the first mixture, optionally in the presence of a catalyst to form a reaction product, distilling the reaction product, and recovering an alkyl hydroxyalkanoate fraction.

Methods and systems for producing alkyl hydroxyalkanoates from hydroxycarboxylic acid recovery bottoms. The methods generally comprise the steps of obtaining a hydroxycarboxylic acid recovery bottom, adding a mono-alcohol to the hydroxycarboxylic acid recovery bottom to obtain a first mixture, heating the first mixture, optionally in the presence of a catalyst to form a reaction product, distilling the reaction product, and recovering an alkyl hydroxyalkanoate fraction.

The invention relates to a composition comprising: at least one alkane-sulphonic acid R—SO.sub.3H wherein R represents a saturated, linear or branched, hydrocarbon chain comprising from 1 to 4 carbon atoms, which can or cannot be substituted by at least one halogen atom; sulphuric acid; and optionally at least one solvent;
of which the proportions are defined in the description. The invention also relates to the use of the composition as a fatty acid esterification catalyst.

The invention relates to a composition comprising: at least one alkane-sulphonic acid R—SO.sub.3H wherein R represents a saturated, linear or branched, hydrocarbon chain comprising from 1 to 4 carbon atoms, which can or cannot be substituted by at least one halogen atom; sulphuric acid; and optionally at least one solvent;
of which the proportions are defined in the description. The invention also relates to the use of the composition as a fatty acid esterification catalyst.

The invention relates to a composition comprising: at least one alkane-sulphonic acid R—SO.sub.3H wherein R represents a saturated, linear or branched, hydrocarbon chain comprising from 1 to 4 carbon atoms, which can or cannot be substituted by at least one halogen atom; sulphuric acid; and optionally at least one solvent;
of which the proportions are defined in the description. The invention also relates to the use of the composition as a fatty acid esterification catalyst.