The US Pharmacopoeia defines paraffin as a solid hydrocarbon mixture obtained from petroleum refining. It is a colorless or white, nearly translucent substance with a crystal structure, odorless and tasteless, and slightly oily when touched.
Paraffin wax consists almost entirely of hydrocarbons, of which most are normal paraffins or few branched alkanes.
Paraffin is a by-product of petroleum refining. It is usually separated from the wax fraction of crude oil. It must be subjected to atmospheric distillation, vacuum distillation, solvent distillation, solvent dewaxing and deoiling, hydrorefining, molding and packaging, these processes.
Paraffin wax is divided into food grade paraffin wax, fully refined paraffin wax, semi refined paraffin wax, scale wax, slack wax,etc.
Paraffin wax is sold in many grades. The main difference is the melting point. According to the melting point, it is divided into No. 52, No. 54, No. 56, No. 58, No. 60, No. 64, No. 66, No. 68, No. 70 paraffin.
The appearance of paraffin wax is white or light yellow crystal. Its chemical composition is a mixture of various alkanes, of which linear normal paraffins account for the majority (>60%), and a few are isoparaffins (about 23-30%) and naphthenic hydrocarbon(<10%).
There is no definite molecular formula of paraffin. The formula is CnHZn+2, where the number of carbon atoms is n=17-36. The larger the n, the higher the melting point of paraffin. The melting point of paraffin is 52-70 ℃, and the relative density is 0.86-0.94. The molecular weight is about 240 to 450. The oil content in the paraffin will lower the melting point and performance.
Paraffin wax has low chemical activity, which is neutral and is chemically stable. It does not react with acid (except nitric acid) and alkaline solution under normal conditions. Paraffin wax is not easily decomposed and carbonized below 140 ℃; it has a certain strength and good plasticity, and is not easy to crack; but the softening point of paraffin wax is low (about 30 ℃), the solidification shrinkage is large, and the surface hardness is small.
Common commercial paraffin wax brands are Amo, Amsco, Mobil,Esso, Shell,Kunlun. Kunlun brand is owned by PetroChina. Ffaith Paraffin Wax cooperates with PetroChina and has its own factory, but the price is much cheaper.