Comparsion of Catalyst Effectiveness in Different Chemical Depolymerization Methods of Poly(ethylene terephthalate).

This paper presents an overview of the chemical recycling methods of polyethylene terephthalate (PET) described in the scientific literature in recent years. The review focused on methods of chemical recycling of PET including hydrolysis and broadly understood alcoholysis of polymer ester bonds including methanolysis, ethanolysis, glycolysis and reactions with higher alcohols. The depolymerization methods used in the literature are described, with particular emphasis on the use of homogeneous and heterogeneous catalysts and ionic liquids, as well as auxiliary substances such as solvents and cosolvents. Important process parameters such as temperature, reaction time, and pressure are compared. Detailed experimental results are presented focusing on reaction yields to allow for easy comparison of applied catalysts and for determination of the most favorable reaction conditions and methods.

Selective Synthesis of Polyoxyethylene-Polyoxypropylene Block Copolymer (Poloxamer) Fatty Acid Monoesters Over Homogeneous Organotin Catalyst.

The synthesis of selected polyoxyethylene-polyoxypropylene block copolymer (poloxamer) fatty acid monoesters is presented. Organotin homogeneous catalyst Sn bis(2-ethylhexanoate) effectively catalyzed the esterification reaction of (EO)-(PO)-(EO) block copolymer (poloxamer) with fatty acids. The reaction proceeded in high yield and high selectivity to monoesters. Content of diesters in final products was below 1 wt%. The new protocol opened up a high yield and high selective method for the synthesis of poloxamer fatty acid monoesters. These products are potentially interesting for industrial applications, e.g. in lubricants, cosmetics and, in particular, as potential emulsifying agents compatible with hydrocarbon bases, such as paraffin.

Synthesis of Fatty Acid Esters of Selected Higher Polyols Over Homogeneous Metallic Catalysts.

Studies on the synthesis of esters of natural origin fatty acids (oleic acid) and a branched synthetic isostearic acid derived from oleic acid with commercially available selected higher polyols in the presence of homogeneous metallic catalysts have been carried out. The effects of the synthesis temperature, molar ratio and the catalysts amount have also been studied. It was shown that higher fatty acid conversion and selectivity to tri- and tetraesters were obtained for organotin catalyst Fascat 2003, which was used as the esterification catalyst. Anti-wear test confirmed good tribological properties of the obtained esters.

Synthesis of novel perfluoroalkylglucosides on zeolite and non-zeolite catalysts.

Perfluoroalkylglucosides comprise a very important class of fluorine-containing surfactants. These compounds can be synthesized by using the Fisher reaction, starting directly from glucose and the required perfluoroalcohols. We wish to report on the use of zeolite catalysts of different structure and composition for the synthesis of perfluoroalkylglucosides when using glucose and 1-octafluoropentanol as substrates. Zeolites of different pore architecture have been chosen (ZSM-5, ZSM-12, MCM-22 and Beta). Zeolites were characterized by XRD, nitrogen sorption, scanning electron microscopy (SEM) and solid-state 27Al MAS NMR spectroscopy. The activity of the zeolite catalysts in the glycosidation reaction was studied in a batch reactor at 100 °C below atmospheric pressure. The performance of zeolites was compared to other catalysts, an ion-exchange resin (Purolite) and a montmorillonite-type layered aluminosilicate. The catalytic performance of zeolite Beta was the highest among the zeolites studied and the results were comparable to those obtained over Purolite and montmorillonite type catalysts.

Hydroxy-Functionalized Basic Ionic Liquids-An Unexpected "Hydroxy" Effect on the Transesterification of Glycerides with Methanol.

New task-specific ionic liquids, hydroxy-functionalized 1-methyl-3-alkylimidazolium hydroxides, were used as catalysts in the transesterification of rapeseed oil with methanol. In comparison to the well-described 1-methyl-3-butylimidazolium hydroxide [bmim]OH, the new ionic liquids show unexpectedly high catalytic activity. In case of the ionic liquid [glymim]OH, which is structurally similar to glycerol, the conversion of rapeseed oil was nearly 100 %.

Synthesis of new fragrances from 2-methylfuran. Part III.

The synthesis of new 2-methylfuran-based alcohols is described. The odor and physicochemical characteristics of all new compounds are also presented.