Abstract:
The invention relates to a method for purifying a composition (I) containing at least one cyclic ketone having 7 to 16 C atoms. The method encompasses the thermal treatment of the composition (I) with at least one acid, then further purification by a method selected from the group consisting of destillation, extraction and crystallization. The invention also relates to a method for producing cyclododecanone, which includes a purification of this type, and to the use of at least one acid for purifying a composition (I) containing at least one cyclic ketone having 7 to 16 C atoms by thermal treatment of the composition (I) with the acid.
Abstract:
The present invention provides a catalyst comprising a mixture of at least one acid-activated sheet silicate with a transition metal oxide of groups 8 and/or 9 of the Periodic Table of the Elements, and also a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers, diesters or monoesters of these polymers, characterized in that tetrahydrofuran is polymerized in the presence of at least one telogen and/or comonomers over such a catalyst.
Abstract:
The object of the present invention is a method for changing the predefined mean molecular weight Mn during the continuous production of polytetrahydrofurane, or tetrahydrofurane copolymers, the monoesters or diesters of polytetrahydrofurane, or tetrahydrofurane copolymers, by the polymerization of tetrahydrofurane in the presence of telogen and/or a comonomer on an acid catalyst, wherein: a) the mol ratio of telogen to tetrohydrofurane, or to tetrahydrofurane and the comonomer, is changed, b) then the mean molecular weight of at least one sample is determined, c) as long as the mean molecular weight determined in this way deviates from the molecular weight to be achieved by the change, the previously formed polytetrahydrofurane, or the tetrahydrofurane copolymers, the monoesters or diesters of the polytetrahydrofurane, or tetrahydrofurane copolymers, are at least partially depolymerized on an acid catalyst, and d) the tetrahydrofurane recaptured by means of depolymerization is returned at least partially to the polymerization process.
Abstract:
The present invention provides a catalyst comprising a mixture of at least one acid-activated sheet silicate with a transition metal oxide of groups 8 and/or 9 of the Periodic Table of the Elements, and also a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers, diesters or monoesters of these polymers, characterized in that tetrahydrofuran is polymerized in the presence of at least one telogen and/or comonomers over such a catalyst.
Abstract:
A method for the breakdown of formates in formate-containing substance mixtures, wherein the formate-containing substance mixtures are reacted in the presence of at least one lanthanum-containing heterogeneous catalyst at a temperature of 80 to 180 °C and at a pressure of 0.1 to 60 bar, and the formate-containing substance mixtures have a pH of 6.5 to 10. Formate-containing substance mixtures is understood to mean, in particular, substance mixtures comprising carbonyl compounds, which were formed, for example, by an aldol reaction of alkanones or alkanals with formaldehyde, such as, for example, methylolalkanals and the respective hydrogenation products thereof. Said products also contain formates in addition to the aforementioned carbonyl compounds.
Abstract:
The invention relates to a method for purifying N-alkylpyrrolidones that contain at least one of the contaminants of formula I or II, in which R stands for hydrogen or a C1 to C20 alkyl group, due to a prior use, characterized in that a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80°C no later than 20 minutes after the addition of the basic compound and N-alkylpyrrolidone is removed from the obtained mixture by distillation.