The present disclosure relates to the formation of terephthalate esters. The present invention also relates to the depolymerization of polyethylene terephthalate (PET) or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) and the recovery of terephthalate esters.

The invention relates to a process for the preparation of an alkanediol and a dialkyl carbonate comprising reacting an alkylene carbonate and an alkanol in the presence of a catalyst, wherein the catalyst is aluminum phosphate.

The invention relates to a process for the preparation of an alkanediol and a dialkyl carbonate comprising reacting an alkylene carbonate and an alkanol in the presence of a catalyst, wherein the catalyst is aluminum phosphate.

The present invention relates to the depolymerization of polymers and the recovery of the starting materials used for the production of the polymer. The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of terephthalic acid and ethylene glycol.

The present invention provides a method for directly preparing glycol dimethyl ether and co-producing ethylene glycol from ethylene glycol monomethyl ether. More specifically, the method comprises passing a feedstock containing a raw material of ethylene glycol monomethyl ether and a carrier gas through a reactor loaded with a solid acid catalyst to produce glycol dimethyl ether and ethylene glycol, at a reaction temperature range from 40 C. to 150 C. and a reaction pressure range from 0.1 MPa to 15.0 MPa; wherein a carrier gas is an optional inactive gas; and the feedstock contains water whose volume concentration in the feedstock is in a range from 0% to 95%; and the weight hourly space velocity of the raw material of ethylene glycol monomethyl ether is in a range from 0.05 h.sup.1 to 5.0 h.sup.1; and the volume concentration of the raw material of ethylene glycol monomethyl ether in the feedstock is in a range from 1% to 100%; and the volume concentration of the carrier gas in the feedstock is in a range from 0% to 99%. In the method of the present invention, using a solid acid as a catalyst and ethylene glycol monomethyl ether as a raw material, under a low temperature condition, glycol dimethyl ether and ethylene glycol are prepared directly with high selectivity; moreover, there is substantially or completely no production of by-product 1,4-dioxane that causes pollution to the environment and is harmful to the human body or animal bodies.

The present invention provides a method for directly preparing glycol dimethyl ether and co-producing ethylene glycol from ethylene glycol monomethyl ether. More specifically, the method comprises passing a feedstock containing a raw material of ethylene glycol monomethyl ether and a carrier gas through a reactor loaded with a solid acid catalyst to produce glycol dimethyl ether and ethylene glycol, at a reaction temperature range from 40 C. to 150 C. and a reaction pressure range from 0.1 MPa to 15.0 MPa; wherein a carrier gas is an optional inactive gas; and the feedstock contains water whose volume concentration in the feedstock is in a range from 0% to 95%; and the weight hourly space velocity of the raw material of ethylene glycol monomethyl ether is in a range from 0.05 h.sup.1 to 5.0 h.sup.1; and the volume concentration of the raw material of ethylene glycol monomethyl ether in the feedstock is in a range from 1% to 100%; and the volume concentration of the carrier gas in the feedstock is in a range from 0% to 99%. In the method of the present invention, using a solid acid as a catalyst and ethylene glycol monomethyl ether as a raw material, under a low temperature condition, glycol dimethyl ether and ethylene glycol are prepared directly with high selectivity; moreover, there is substantially or completely no production of by-product 1,4-dioxane that causes pollution to the environment and is harmful to the human body or animal bodies.

The present invention provides a method for directly preparing glycol dimethyl ether and co-producing ethylene glycol from ethylene glycol monomethyl ether. More specifically, the method comprises passing a feedstock containing a raw material of ethylene glycol monomethyl ether and a carrier gas through a reactor loaded with a solid acid catalyst to produce glycol dimethyl ether and ethylene glycol, at a reaction temperature range from 40 C. to 150 C. and a reaction pressure range from 0.1 MPa to 15.0 MPa; wherein a carrier gas is an optional inactive gas; and the feedstock contains water whose volume concentration in the feedstock is in a range from 0% to 95%; and the weight hourly space velocity of the raw material of ethylene glycol monomethyl ether is in a range from 0.05 h.sup.1 to 5.0 h.sup.1; and the volume concentration of the raw material of ethylene glycol monomethyl ether in the feedstock is in a range from 1% to 100%; and the volume concentration of the carrier gas in the feedstock is in a range from 0% to 99%. In the method of the present invention, using a solid acid as a catalyst and ethylene glycol monomethyl ether as a raw material, under a low temperature condition, glycol dimethyl ether and ethylene glycol are prepared directly with high selectivity; moreover, there is substantially or completely no production of by-product 1,4-dioxane that causes pollution to the environment and is harmful to the human body or animal bodies.

The present disclosure relates to the formation of terephthalate esters. The present invention also relates to the depolymerization of polyethylene terephthalate (PET) or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) and the recovery of terephthalate esters

The presently claimed invention relates to a process for the recovery of 3-methyl-3-buten-1-ol from a stream obtained in the production of 3-methyl-3-buten-1-ol from 2-methylprop-1-ene and formaldehyde, by treating the stream with an amine catalyst.

The disclosure relates to a method for chemically recycling a condensation polymer, which includes melt-processing a mixture including a condensation polymer and an internal catalyst to increase the amorphous content of the polymer, followed by depolymerizing polymer in a reaction medium with a reactive solvent. Melt-processing and quenching of a condensation polymer generally reduces the crystalline content of the polymer and correspondingly increases the amorphous content of the polymer, which makes the polymer more amenable to subsequent depolymerization. Inclusion of the internal catalyst, for example a volatile organic catalyst, during melt-processing not only improves the relative degree of amorphization during melt-processing, but it also enhances the rate and conversion of the depolymerization stage that would otherwise be rate-limited by mass transport of an external catalyst from the bulk reaction medium to the polymer surface for depolymerization.