coal tar
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.
Noun
-
a tar formed from distillation of bituminous coal; coal tar can be further distilled to give various aromatic compounds
Khám phá thêm
Các từ liên quan
Từ chứa "coal tar"
