Oils/waxes molecular weight range

In both solvents, the 6 1 and 3 1 ratios produced polysilazane oils with molecular weights in the range 390-401 g/mol and 480 g/mol, respectively. When a 1 1 reactant ratio was used, waxes of somewhat higher (764-778 g/mol) molecular weights were obtained in both solvents. In the 1 1 reaction carried out in Et2<3 the yield of soluble product was only 40%, but in THF it was nearly quantitative. 

Molecular Weight Range of Pyrolysis Oils/Waxes... 

Poly(oxytetramethylene), poly(tetrahydrofuran), may assume the state of a viscous oil, a wax, or a crystalline solid (melting range around 55 °C), depending on the molecular weight. Poly(tetrahydrofuran) telechelics prepared with two OH end groups and in molar masses of 500-4000 g/mol are used widely as soft block in segmented polyurethanes and polyesters (see Sect. 3.4.2.1). 

Alkanes are used primarily as fuels, solvents, and lubricants. Natural gas, gasoline, kerosene, heating oil, lubricating oil, and paraffin wax are all composed primarily of alkanes, with different physical properties resulting from different ranges of molecular weights. 

Lubricating oil. A new process has been developed for the conversion of waste plastic and Fischer-Tropsch (FT) wax to lube range molecules that can be hydroisomerized to low pour point lube base oils of unconventional base oil (UCBO) quality. The process employs pyrolysis, a thermal, noncatalytic, low-pressure reaction where high-molecular-weight molecules are cracked to ones of lower molecular weight. The major by-product is diesel, with little production of C4- gas. The by-product liquids are highly olefinic and could be oligomerized to provide additional base oil. 

Selective extracts obtained in the pressure range around 100 bar contain only small volatile molecules like mono- and sesquiterpenes. Thus they are similar to conventional steam distillates (essential oils). Total extracts recovered in the pressure range around 300 bar contain in addition higher molecular weight lipophilic constituents like fatty oils, resins and waxes and thus are comparable to classical hexane extracts (oleoresins). Consequently supercritical C02-extraction is the only procedure which produces completely different extracts from one and the same raw material on the same equipment. 

The waxy oil is fractionated to produce an oily wax called slack wax. This is separated by solvent extraction and fractionated into different melting point ranges to give waxes with a variety of physical characteristics. Paraffin waxes consist mainly of straight-chain alkanes (also called normal alkanes), with small amounts (3-15%) of branched-chain alkanes (or iso-alkanes), cycloalkanes, and aromatics. Microcrystalline waxes contain high levels of branched-chain alkanes (up to 50%) and cycloalkanes, particularly in the upper end of the molecular weight distribution. Paraffin waxes contain alkanes up to a molecular mass of approximately 600 amu, whereas microcrystalline waxes can contain alkanes up to a molecular mass of approximately 1100 amu. 

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