Provided is a method for purifying an alkylene glycol monoalkyl ether carboxylic acid ester (AGAECE) for photoresist processing, wherein the method comprises the step of distillation after passing industrial AGAECE through a porous adsorbent impregnated with a basic material, and it is possible to obtain a semiconductor-grade high-purity AGAECE maintaining a low acid value and high purity according to the present invention.

Provided is a process for depolymerization of a poly(C.sub.2-C.sub.4 alkylene terephthalate), which comprises contacting a poly(C.sub.2-C.sub.4 alkylene terephthalate) with methanol and a catalyst chosen from potassium carbonate, sodium carbonate, magnesium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, and triazabicyclodecene, at a temperature sufficient to effect said depolymerization. The process of the invention can be carried out a substantially lower temperature and requires less methanol than necessary for zinc acetate-catalyzed reactions, and is sufficiently robust to tolerate lower-quality poly(C.sub.2-C.sub.4 alkylene terephthalate) scrap feeds.

Provided is a process for depolymerization of a poly(C.sub.2-C.sub.4 alkylene terephthalate), which comprises contacting a poly(C.sub.2-C.sub.4 alkylene terephthalate) with methanol and a catalyst chosen from potassium carbonate, sodium carbonate, magnesium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, and triazabicyclodecene, at a temperature sufficient to effect said depolymerization. The process of the invention can be carried out a substantially lower temperature and requires less methanol than necessary for zinc acetate-catalyzed reactions, and is sufficiently robust to tolerate lower-quality poly(C.sub.2-C.sub.4 alkylene terephthalate) scrap feeds.

Provided is a process for depolymerization of a poly(C.sub.2-C.sub.4 alkylene terephthalate), which comprises contacting a poly(C.sub.2-C.sub.4 alkylene terephthalate) with methanol and a catalyst chosen from potassium carbonate, sodium carbonate, magnesium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, and triazabicyclodecene, at a temperature sufficient to effect said depolymerization. The process of the invention can be carried out a substantially lower temperature and requires less methanol than necessary for zinc acetate-catalyzed reactions, and is sufficiently robust to tolerate lower-quality poly(C.sub.2-C.sub.4 alkylene terephthalate) scrap feeds.

In methods for preparing an alkyl carboxylic acid ester according to embodiments of the present invention, a first reaction product is produced by reaction of a carboxylic acid stream and a first alcohol stream in a preliminary reactor. A second reaction product is produced by at least partially removing alcohol and water from the first reaction product. The second reaction product is esterified by reaction with a second alcohol stream in a main reactor. An alkyl carboxylic acid ester is recovered from the main reactor.

In methods for preparing an alkyl carboxylic acid ester according to embodiments of the present invention, a first reaction product is produced by reaction of a carboxylic acid stream and a first alcohol stream in a preliminary reactor. A second reaction product is produced by at least partially removing alcohol and water from the first reaction product. The second reaction product is esterified by reaction with a second alcohol stream in a main reactor. An alkyl carboxylic acid ester is recovered from the main reactor.

In methods for preparing an alkyl carboxylic acid ester according to embodiments of the present invention, a first reaction product is produced by reaction of a carboxylic acid stream and a first alcohol stream in a preliminary reactor. A second reaction product is produced by at least partially removing alcohol and water from the first reaction product. The second reaction product is esterified by reaction with a second alcohol stream in a main reactor. An alkyl carboxylic acid ester is recovered from the main reactor.

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.

A process for chemically recycling polyethylene terephthalate (PET) which utilizes a microwave absorber to optimize glycolytic depolymerization of PET via microwave irradiation. The method of chemically degrading PET to its reactive intermediate, bis(2-hydroxyethyl) terephthalate (BHET), is carried out by: (a) combining PET with ethylene glycol and a catalytic system comprising a catalyst and a microwave absorber to produce a heterogeneous reaction mixture; and then (b) heating by microwave irradiating the reaction mixture to a temperature sufficient to produce a reaction product comprising BHET. The BHET monomer then can be purified and re-polymerized to form new, virgin PET.