The present disclosure relates to microporous magnesium alkoxide and its preparation. The magnesium alkoxide of the present disclosure is characterized by mean particle size ranging from 20 to 70; surface area ranging from 1 to 30 m.sup.2/g; circularity ranging from 0.5 to 0.9; macro pore size distribution ranging from 40 to 80%; meso pore size distribution ranging from 15 to 60%; and micro pore size distribution ranging from 2 to 10%.

The present disclosure relates to microporous magnesium alkoxide and its preparation. The magnesium alkoxide of the present disclosure is characterized by mean particle size ranging from 20 to 70; surface area ranging from 1 to 30 m.sup.2/g; circularity ranging from 0.5 to 0.9; macro pore size distribution ranging from 40 to 80%; meso pore size distribution ranging from 15 to 60%; and micro pore size distribution ranging from 2 to 10%.

The purpose of the present invention is to provide a spherical or ellipsoidal magnesium alcoholate having a narrow particle size distribution even when the particle size is small.

The present invention provides a method for producing a magnesium alcoholate by adding in a portionwise manner to a reaction system and reacting, metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound in the reaction system under alcohol reflux, which is a method for producing a magnesium alcoholate characterized in that a mixture of metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound is added to the reaction system at each portionwise addition.

The purpose of the present invention is to provide a spherical or ellipsoidal magnesium alcoholate having a narrow particle size distribution even when the particle size is small.

The present invention provides a method for producing a magnesium alcoholate by adding in a portionwise manner to a reaction system and reacting, metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound in the reaction system under alcohol reflux, which is a method for producing a magnesium alcoholate characterized in that a mixture of metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound is added to the reaction system at each portionwise addition.

The purpose of the present invention is to provide a spherical or ellipsoidal magnesium alcoholate having a narrow particle size distribution even when the particle size is small.

The present invention provides a method for producing a magnesium alcoholate by adding in a portionwise manner to a reaction system and reacting, metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound in the reaction system under alcohol reflux, which is a method for producing a magnesium alcoholate characterized in that a mixture of metallic magnesium, an alcohol, and at least one of a halogen or a halogen atom-containing compound is added to the reaction system at each portionwise addition.

The present invention relates to a process for depolymerising polyethylene terephthalate (PET), in which method PET is reacted with sodium glycolate or potassium glycolate, which has been obtained by reactive distillation, to form a mixture M.sub.1 including Bis(2-hydroxyethyl) terephthalate (BHET). The process according to the invention is distinguished by the fact that BHET makes up a particularly high proportion of the decomposition products in the mixture M.sub.1. The process according to the invention thus provides a high yield of BHET that can be used directly for producing PET again. The present invention thus also relates to a process for recycling PET, in which the BHET obtained in the process for depolymerising PET is polymerised again to form PET, optionally after being further purified from M.sub.1.

A method of producing an alkali metal alkoxide involves the following steps: (i) providing an organic compound having at least one-OH group and having a molecular weight of 75 to 750 g/mol in a reaction vessel in an inert atmosphere; (ii) adding a C.sub.1-6 alkali metal alcoholate to obtain a reaction mixture; (iii) heating the reaction mixture of step (ii) under stirring to 25 to 180 C. to obtain the alkali metal alkoxide and a C.sub.1-6 alcohol; and (iv) distilling off the obtained C.sub.1-6 alcohol. While distilling, at least one non-polar solvent having a boiling point higher than the obtained alcohol is continuously or batchwise added to the mixture.

A method of producing an alkali metal alkoxide involves the following steps: (i) providing an organic compound having at least one-OH group and having a molecular weight of 75 to 750 g/mol in a reaction vessel in an inert atmosphere; (ii) adding a C.sub.1-6 alkali metal alcoholate to obtain a reaction mixture; (iii) heating the reaction mixture of step (ii) under stirring to 25 to 180 C. to obtain the alkali metal alkoxide and a C.sub.1-6 alcohol; and (iv) distilling off the obtained C.sub.1-6 alcohol. While distilling, at least one non-polar solvent having a boiling point higher than the obtained alcohol is continuously or batchwise added to the mixture.

The present invention relates to a process for producing at least one alkali metal methoxide by reactive distillation in at least one reaction column. At the lower end of the reaction column(s), the respective alkali metal methoxide dissolved in methanol is withdrawn. The methanol/water mixture obtained at the top of the reaction column(s) is separated by distillation in a rectification column. The energy from the vapour obtained at the top of the rectification column is transferred to a liquid or gaseous heat transfer medium, and the gaseous heat transfer medium obtained as a result is compressed in at least two stages. The energy from the respectively compressed heat transfer medium is advantageously transferred to the bottom stream and sidestream from the rectification column. This enables particularly energy-efficient use of the energy from the vapour in the process of the invention. The energy from the compressed heat transfer medium may additionally be used for operation of the reaction column(s) or for operation of a reaction column in which a process for transalcoholization of alkali metal alkoxides is conducted.

The present invention relates to a process for producing at least one alkali metal methoxide by reactive distillation in at least one reaction column. At the lower end of the reaction column(s), the respective alkali metal methoxide dissolved in methanol is withdrawn. The methanol/water mixture obtained at the top of the reaction column(s) is separated by distillation in a rectification column. The energy from the vapour obtained at the top of the rectification column is transferred to a liquid or gaseous heat transfer medium, and the gaseous heat transfer medium obtained as a result is compressed in at least two stages. The energy from the respectively compressed heat transfer medium is advantageously transferred to the bottom stream and sidestream from the rectification column. This enables particularly energy-efficient use of the energy from the vapour in the process of the invention. The energy from the compressed heat transfer medium may additionally be used for operation of the reaction column(s) or for operation of a reaction column in which a process for transalcoholization of alkali metal alkoxides is conducted.