Perchloroethylene

Brief Overview

Perchloroethylene, also known as perc, is a colorless, nonflammable liquid solvent with a sweet, ether-like odor. The growth in demand for perchloroethylene is attributable to dry cleaning, vapor-degreasing, and other technical and industrial applications. While one-fourth of PCE
supply is consumed for the production of chlorofluorocarbon, its popularity as a solvent has been driving sales in the paint and coating industry. PCE is available commercialy in several grade such as Degreasing & General Purpose Grade, Fluorocarbon Grade, Dry Cleaning Grade, and other (Catalyst/Refinery Grade & Custom Grade). It typically has a purity of 95% or more for dry-cleaning and industrial grades, 99% or more for more refined grades, and 99.995% for isomerization and fluorocarbon grades. The various grades differ in the amount and type of stabilizers added to prevent decomposition.

Manufacturing process

For many years, the most important process for producing PCE was from acetylene via trichloroethylene, but because of the increasing price of acetylene feedstock, newer processes involving direct chlorination or oxychlorination of other hydrocarbons were introduced. It can also be made by reacting chlorine with C1-C3 hydrocarbons, with ethane being the most favoured, or from chlorinated hydrocarbon wastes in a tubular or fluidised bed reactor. Increasing environmental pressures on the disposal of wastes containing chlorine have made
this a growing source of perchloroethylene. The process can be carried out by high temperature chlorination, and low pressure and high pressure chlorinolysis. The low pressure route is the most popular as it facilitates the purification of the HCl formed.
Recycled PCE is produced from waste solvent recycling process. The process normally incorporate some steps such as initial treatment, distillation, purification, then reclaimed solvent will be stored.

Dry Cleaning
Perchloroethylene is a solvent commonly used in dry cleaning operations. When applied to a material or fabric, perc helps dissolve greases, oils and waxes without damaging the fabric.

Metal manufacture 
PCE is used as a degreasing agent in vapour and liquid forms. Solvents containing PCE clean and degrease new metal to help prevent impurities from weakening the metal.

Textile
In textile processing, tetrachloroethylene is used as a solvent to remove oils from fabrics after knitting and weaving operations, and as a carrier solvent for scouring, sizing and desizing, and for fabric finishes and water repellents. PCE is able to dissolve fats, greases, waxes, and oils without harming natural or synthetic fibres.

Printing Industry

Flexographic printing is a method that is similar to letterpress printing, but uses flexible plates. PCE is used to clean unpolymerized coatings from the flexible film. The cleaning is performed in automated enclosed machinery.

Consumer
Due to its durability and ability to adhere to plastics, metal, rubber and leather, perchloroethylene has been used as an ingredient in a range of common products such as water repellants, paint removers, printing inks, glues, sealants, polishes and lubricants.