Different Forms of Paraffin Waxes
Paraffin or hydrocarbons is a linear or branched saturated organic compound constituting CnH2n+2. Paraffin is used in the mixture of hydrocarbons of various groups(especially paraffin and naphthenes) in solid state at room temperature.
Organic paraffin wax is abundant in nature, but it can also be produced by synthetic production and as a by-product when processing certain natural substances. Low molecular weight paraffinic hydrocarbons are present in natural gas, while medium and high molecular weight paraffinic hydrocarbons are present in petroleum and natural mineral waxes.
In the industry, it is possible to produce paraffin wax from coal by well-known Fischer-Tropsch synthesis method, or to obtain paraffin wax from tar obtained by dry distillation of coal(mainly lignite) and other organic matter( wood, asphaltene shale, fish fat,etc.).
Liquid paraffin wax at room temperature is produced from kerosene and diesel fraction obtained by atmospheric distillation of crude oil. Solid paraffin wax at room temperature is produced from lubricating oil fractions of different melting points, from vacuum residue and from the tank bottom wax and pipe wax precipitated from the crude oil storage and transportation process.
Various types of paraffin wax are divided into major categories: coarse crystalline paraffin and microcrystalline paraffin. Paraffin wax is made of saturated normal paraffin, a small amount of isoparaffins and naphthenes. Each component has a molecular weight of 250 to 450, a melting point of 40 to 60 ℃, and a crystal form of a sheet or a needle.
In addition to normal paraffins, microcrystalline waxes contain a large amount of isoparaffins and long alkyl side chain cycloalkanes. The isoparaffins form microcrystalline waxes. The main part of the microcrystalline wax is a C40-C56 compound with a melting point of 60-90 ℃.