C5-fraction is the C5 fraction. The main components are cyclopentadiene and isoprene. Available for separation. Mainly refers to the process of oil cracking ethylene process by-product containing five carbon atoms of the hydrocarbon mixture. When naphtha is cracked to produce ethylene, the by-product carbon fractions (about 15% of the amount of ethylene) have less paraffin content and higher diene content. Of these, isoprene and cyclopentadiene are about 15% Pentadiene accounts for about 10%.

Uses:
Carbon five fractions can be directly made of petroleum resin, widely used in adhesives, coatings, printing inks, paper gluing agent, etc., can also be used extraction distillation, absorption and other isolated isoprene, cyclopentadiene, P-pentadiene, isopentene, n-pentene, etc., are widely used in the preparation of synthetic rubber, coatings and other petrochemical products and fine chemical products. Isopentane can be dehydrogenated to isoprene. Isoprene is used to make synthetic rubber and other polymers. Cyclopentadiene for the manufacture of pesticides and so on. Carbon fractions can also be used as fuel and raw materials for carbon black.

C5 mainly from the high temperature cracking of petroleum hydrocarbons to ethylene process by-product C5 fractions and oil refinery catalytic cracking unit. However, the composition and use of the C5 fractions from two different sources are very different. The olefins in the C5 fraction of the refinery catalytic cracking unit are mainly monoolefins, and the higher value component in the chemical utilization is isopentene. The higher value components used in the byproduct C5 fraction of the pyrolysis ethylene process are isoprene, cyclopentadiene and p-pentadiene. The by-product C5 fraction, which is produced by cracking to ethylene, is separated to produce isoprene, cyclopentadiene, dicyclopentadiene and petroleum resin. Isoprene is an extremely important C5 diene, the main purpose is to produce polyisoprene rubber, SIS copolymer and butyl rubber. Its chemical nature of lively, through a variety of chemical reactions can be synthetic spices, pesticides, pharmaceuticals and other fine chemical products. Dicyclopentadiene contains a number of unsaturated double bonds, the chemical properties are very lively, with a variety of compounds can be generated to produce a wide range of derivatives. Mainly used in the production of C5 alicyclic petroleum resin, unsaturated polyester resin, poly dicyclopentadiene and ethylene propylene rubber.