Chlorinated paraffins

Chlorinated paraffins

Chlorinated paraffins are a complex group of polychlorinated alkanes that are characterized by the presence of chlorine atoms attached to carbon atoms in a carbon chain. These compounds are categorized based on their carbon chain length into short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs), and long-chain chlorinated paraffins (LCCPs). Chlorinated paraffins are primarily used as flame retardants and plasticizers in a wide range of materials, including PVC, paints, rubber products, and sealants.

Production and Properties

Chlorinated paraffins are produced by the chlorination of n-paraffin or paraffin wax, which involves the reaction of paraffin with chlorine gas at high temperatures. The degree of chlorination can vary, resulting in products with varying levels of chlorine content, typically ranging from 30% to 70% by weight. The physical and chemical properties of chlorinated paraffins, such as viscosity, density, and chemical stability, depend on the length of the carbon chain and the degree of chlorination.

Applications

The primary applications of chlorinated paraffins are as secondary plasticizers in PVC and as flame retardants in various materials. SCCPs, due to their short carbon chain length, are more efficient as flame retardants and are commonly used in rubber, textiles, and various plastics. MCCPs and LCCPs, with their longer carbon chains, are mainly used as plasticizers in PVC, improving the flexibility and durability of the material. Additionally, chlorinated paraffins serve as lubricant additives in metalworking fluids, enhancing the performance and lifespan of cutting tools.

Environmental and Health Concerns

Chlorinated paraffins have raised environmental and health concerns due to their persistence, bioaccumulation potential, and toxicity. SCCPs, in particular, have been identified as Persistent Organic Pollutants (POPs) under the Stockholm Convention, leading to restrictions and phase-outs in several countries. The primary concerns associated with chlorinated paraffins are their potential to cause long-term adverse effects in the environment, including toxicity to aquatic organisms, and their potential human health risks, including carcinogenicity and endocrine disruption.

Regulation and Management

The production and use of chlorinated paraffins are regulated under various international and national regulations. The Stockholm Convention on Persistent Organic Pollutants targets the elimination or restriction of SCCPs. Additionally, regulatory bodies in many countries have established guidelines and limits for the use of chlorinated paraffins in products, aiming to reduce human and environmental exposure. Ongoing research and assessment are crucial for understanding the full extent of the impacts of chlorinated paraffins and for developing safer alternatives.