The present disclosure relates to the formation of dimethyl terephthalate (DMT). The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of dimethyl terephthalate (DMT).

Process for purifying bis(2-hydroxyethyl)terephthalate (BHET) obtained from depolymerization of a polyethylene terephthalate (PET) waste, the process comprising: treating said solution with at least one oxidizing agent at a temperature of from 30° C. to 100° C., preferably from 50° C. to 90° C., to obtain an oxidized solution; treating the oxidized solution with at least one adsorbing agent to obtain a purified oxidized solution; separating the at least one adsorbing agent from the purified oxidized solution to obtain a purified BHET solution. This process is particularly effective for eliminating organic dyes and other low molecular weight organic contaminants, so as to achieve a high purity degree of the recovered BHET.

Process for purifying bis(2-hydroxyethyl)terephthalate (BHET) obtained from depolymerization of a polyethylene terephthalate (PET) waste, the process comprising: treating said solution with at least one oxidizing agent at a temperature of from 30° C. to 100° C., preferably from 50° C. to 90° C., to obtain an oxidized solution; treating the oxidized solution with at least one adsorbing agent to obtain a purified oxidized solution; separating the at least one adsorbing agent from the purified oxidized solution to obtain a purified BHET solution. This process is particularly effective for eliminating organic dyes and other low molecular weight organic contaminants, so as to achieve a high purity degree of the recovered BHET.

A method for alcoholising and hydrolysing polyurethane (PUR) materials made from at least one polyol compound and at least one toluene diisocyanate based compound; wherein the method comprises the following steps: contacting the polyurethane material with at least one alcoholising compound, thereby forming a reaction mixture (M.sub.0) and allowing the polyurethane material and the alcoholising compound to react in said reaction mixture (M.sub.0), thereby forming a mixture (M); allowing the mixture (M) to separate into at least an upper phase and a lower phase, wherein phase (A) and phase (B) are two immiscible phases; subjecting phase (B) to at least one hydrolysis step, thereby forming a phase (B1); wherein the at least one alcoholising compound is characterized by a melting point of lower than 200° C.; wherein the at least one alcoholising compound is characterized by a hydroxyl functionality of at least 2; and with the proviso that the at least one alcoholising compound is not glycerol.

A method for alcoholising and hydrolysing polyurethane (PUR) materials made from at least one polyol compound and at least one toluene diisocyanate based compound; wherein the method comprises the following steps: contacting the polyurethane material with at least one alcoholising compound, thereby forming a reaction mixture (M.sub.0) and allowing the polyurethane material and the alcoholising compound to react in said reaction mixture (M.sub.0), thereby forming a mixture (M); allowing the mixture (M) to separate into at least an upper phase and a lower phase, wherein phase (A) and phase (B) are two immiscible phases; subjecting phase (B) to at least one hydrolysis step, thereby forming a phase (B1); wherein the at least one alcoholising compound is characterized by a melting point of lower than 200° C.; wherein the at least one alcoholising compound is characterized by a hydroxyl functionality of at least 2; and with the proviso that the at least one alcoholising compound is not glycerol.

A method for recycling polyethylene terephthalate (PET) to produce bis(2-hydroxyethyl) terephthalate (BHET) comprises the steps of (a) depolymerising PET in the presence of ethylene glycol and a catalyst system in a series of preferably two depolymerisation reactors to form a depolymerised mixture comprising BHET; (b) crystallising a precipitate comprising BHET from the depolymerised mixture; (c) dissolving the precipitate in a protic solvent, preferably water, but also optionally methanol, to form a solution comprising BHET; (d) removing impurities from the solution to form a purified solution comprising BHET; and (e) crystallising a purified product comprising BHET from the purified solution. Suitable apparatus for such a method, and the use of urea in a catalyst system therefor, are also provided.

A method for recycling polyethylene terephthalate (PET) to produce bis(2-hydroxyethyl) terephthalate (BHET) comprises the steps of (a) depolymerising PET in the presence of ethylene glycol and a catalyst system in a series of preferably two depolymerisation reactors to form a depolymerised mixture comprising BHET; (b) crystallising a precipitate comprising BHET from the depolymerised mixture; (c) dissolving the precipitate in a protic solvent, preferably water, but also optionally methanol, to form a solution comprising BHET; (d) removing impurities from the solution to form a purified solution comprising BHET; and (e) crystallising a purified product comprising BHET from the purified solution. Suitable apparatus for such a method, and the use of urea in a catalyst system therefor, are also provided.

Method for depolymerising terephthalate polymer into reusable raw material, the method comprising steps of: depolymerizing terephthalate polymer by using ethylene glycol into a depolymerised mixture comprising at least one monomer and at least one dimer, wherein said at least one monomer comprises bis (2-hydroxyethyl) terephthalate (BHET), and said at least one dimer comprises dimer of bis (2-hydroxyethyl) terephthalate (BHET-dimer); removing solid compounds from said depolymerised mixture in a first separator to obtain a composition comprising the at least one dimer and the at least one monomer as solutes in a mixture of ethylene glycol and water; crystallizing BHET-dimer from said solution, thereby obtaining a mixture of BHET-dimer crystals and a first mother liquid; separating the crystallized BHET-dimer from the first mother liquid, and thereafter: forming BHET crystals from said first mother liquid, thereby obtaining a mixture of BHET crystals and a second mother liquid; and recovering the BHET crystals.

Method for depolymerising terephthalate polymer into reusable raw material, the method comprising steps of: depolymerizing terephthalate polymer by using ethylene glycol into a depolymerised mixture comprising at least one monomer and at least one dimer, wherein said at least one monomer comprises bis (2-hydroxyethyl) terephthalate (BHET), and said at least one dimer comprises dimer of bis (2-hydroxyethyl) terephthalate (BHET-dimer); removing solid compounds from said depolymerised mixture in a first separator to obtain a composition comprising the at least one dimer and the at least one monomer as solutes in a mixture of ethylene glycol and water; crystallizing BHET-dimer from said solution, thereby obtaining a mixture of BHET-dimer crystals and a first mother liquid; separating the crystallized BHET-dimer from the first mother liquid, and thereafter: forming BHET crystals from said first mother liquid, thereby obtaining a mixture of BHET crystals and a second mother liquid; and recovering the BHET crystals.

A process for producing recycle polyesters made from organic compounds, e.g., acids and alcohols, derived from recycled, reused or other environmentally favored raw materials by obtaining a recycle monomer composition derived directly or indirectly from cracking a recycle content pyrolysis oil composition and reacting the recycle monomer with recycle DMT obtained directly or indirectly from the depolymerization of terephthalate polyesters to prepare a recycle polyester.