coal tar

Thân thiện

A worker handles coal tar at an industrial plant.

Definition

Noun: A thick, black, viscous liquid produced by the destructive distillation of bituminous coal. It is a complex mixture of hundreds of organic compounds, primarily aromatic hydrocarbons like benzene, toluene, naphthalene, and phenols. Coal tar is a primary raw material in the chemical industry for producing various synthetic materials, dyes, drugs, and perfumes.

Usage and Examples

• As a raw material:
  • Coal tar is a key starting point for manufacturing many industrial chemicals.
  • The distinctive smell of some road-paving materials comes from coal tar derivatives.
• In historical/medical contexts:
  • Coal tar was once widely used in medicated soaps and shampoos for skin conditions.
  • Early synthetic dyes were derived from coal tar.

Advanced Usage

• "Coal tar pitch": A specific residue obtained from the distillation of coal tar, used as a binder or waterproofing agent.
  • Coal tar pitch is commonly used in the production of electrodes for aluminum smelting.
• "Coal tar derivatives": Refers to the numerous chemical compounds isolated or synthesized from coal tar.
  • Pharmaceuticals like aspirin were historically developed from coal tar derivatives.

Variants and Related Words

• Creosote: A product obtained from the distillation of coal tar, used as a wood preservative.
• Pitch: Often used synonymously with coal tar or, more specifically, to refer to its thicker, residual forms.
• Bitumen: A related but distinct viscous substance derived from petroleum, not coal.

Synonyms

• Coal-tar (hyphenated variant)
• Tar (in specific industrial contexts, though "tar" can also come from wood or petroleum)

Related Phrases and Compounds

• Coal tar soap: A soap containing coal tar, historically used for its antiseptic properties.
• Coal tar enamel: A protective coating for steel pipes, made from coal tar.

Notes on Meaning

The term 'coal tar' specifically denotes the product from coal. It is not used for similar-looking substances derived from other sources (e.g., "pine tar"). Its primary modern significance is industrial and chemical, rather than as a common end-product itself.

Học thuật

Noun

1. a tar formed from distillation of bituminous coal; coal tar can be further distilled to give various aromatic compounds