entchlort

Entchlort is a German term that denotes the removal of chlorine atoms from a molecule or material. In English, the corresponding adjective is dechlorinated. The concept appears in chemistry, environmental science, and water-treatment contexts to describe compounds that no longer carry chlorine substituents and the processes by which those substituents are eliminated.

In practice, dechlorination can be chemical, biological, or physical. Chemical dechlorination uses reducing agents such as sodium metabisulfite, sodium bisulfite, or zinc in suitable systems, and may include catalytic hydrodechlorination with hydrogen over metal catalysts. Biological dechlorination, or reductive dehalogenation, is carried out by specialized microbes under anaerobic conditions, progressively removing chlorine atoms from organochlorines to yield less chlorinated products or hydrocarbons. In water treatment, dechlorination refers to the removal of residual chlorine from treated water to protect aquatic ecosystems, often achieved with chemical reductants like sodium sulfite or ascorbic acid.

The term is commonly applied to environmental cleanup efforts involving chlorinated pollutants (for example, certain solvents and pesticides) and to synthetic chemistry where dechlorinated products serve as intermediates or end products. The degree of dechlorination and the resulting compound’s properties—such as polarity, reactivity, and toxicity—depend on how many and which chlorine atoms are removed.

See also: dechlorination, chlorination, organochlorines, reductive dehalogenation, water treatment.