A method with typical green and low-carbon characteristics for preparing recycled polyester by closed-loop recycling of waste polyester is disclosed. The method includes subjecting the waste polyester to depolymerization by using a specific depolymerization catalyst; removing a polyol solvent from a depolymerization product, and removing a by-product by purification to obtain a depolymerization monomer; mixing the depolymerization monomer with a binary acid, a polyol, a polymerization catalyst, and a chain extender to carry out an esterification reaction; and then adding a stabilizer and a catalyst for condensation polymerization to obtain the recycled polyester. The method of the present invention has low depolymerization temperature, high efficiency, low use amount of the polyol solvent, and extremely low content of a by-product. Meanwhile, the depolymerization catalyst can be directly used for the co-esterification of the recycled polyester without separation, and adverse effects on properties of the prepared recycled polyester cannot be caused.

Methods for making acrylic acid, acrylic acid derivatives, or mixtures thereof by contacting a stream containing hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof with either an active catalyst containing an amorphous and partially-dehydrated phosphate salt or a precursor catalyst containing a crystalline phosphate salt in a reactor with a low corrosion rate are provided.

A catalyst comprising a platinum group metal (group 10) supported on a carrier, said carrier comprising a silica core and a precipitate layer of comprising a metal oxide, sulfate or phosphate on said core; said catalyst also comprising a rhodium group metal (group 9) supported on said carrier.

Processes for synthesizing 5-hydroxymethylfurfural are described. The processes comprise contacting a feed comprising biomass-derived cellulose, or a sugar monomer or oligomer, or a mixture thereof with a catalyst comprising a metal phosphate. The metal phosphate may comprise hafnium phosphate, or zirconium phosphate, or combinations thereof. The catalyst has a ratio of Bronsted acid sites to Lewis acid sites greater than or equal to 0.27 and a total acid density less than or equal to 0.4.

A composition contains a phosphonium catalyst and a polyorganohydrogensiloxane. The composition is curable in a method including heating. The composition and method are useful for preparing polyorganosiloxane products such as coatings, adhesives, elastomers, and foams.