acid anhydride
LowTechnical/Scientific
Definition
Meaning
A chemical compound formed by removing water from two acid molecules, often reactive and used in synthesis.
In organic chemistry, a compound that reacts with water to form two carboxylic acid molecules; in inorganic chemistry, oxides of nonmetals that react with water to form acids.
Linguistics
Semantic Notes
The term is almost exclusively used in chemistry contexts. It refers to a functional group or class of compounds rather than a single substance. 'Anhydride' literally means 'without water'.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling follows regional norms for other words in the sentence.
Connotations
Identical technical connotations in both varieties.
Frequency
Equally low frequency in specialised chemistry texts in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
[acid anhydride] + [reacts with] + [water/alcohol/amine][synthesise] + [acid anhydride] + [from] + [acid][acid anhydride] + [is used as] + [acylating agent]Vocabulary
Synonyms
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Virtually never used outside chemical manufacturing or pharmaceutical R&D reports.
Academic
Used in chemistry, biochemistry, and chemical engineering textbooks, papers, and lectures.
Everyday
Extremely rare; would only appear in advanced educational contexts or popular science articles.
Technical
Core term in organic synthesis, polymer chemistry, and industrial chemical processes.
Examples
By Part of Speech
adjective
British English
- The acid anhydride compound was handled under nitrogen.
- An acid anhydride functional group is highly reactive.
American English
- The acid anhydride reagent was stored in a desiccator.
- Acid anhydride chemistry is fundamental to polymer synthesis.
Examples
By CEFR Level
- Acid anhydrides are important in making some medicines.
- The chemist used an acid anhydride in the experiment.
- Acetic anhydride, a common acid anhydride, is used to produce aspirin.
- The reaction involves the slow addition of the acid anhydride to the alcohol.
- The mechanism proceeds via nucleophilic attack on the carbonyl carbon of the acid anhydride.
- Symmetrical acid anhydrides are named by replacing 'acid' with 'anhydride' in the parent acid name.
Learning
Memory Aids
Mnemonic
Think: 'AN-HY-DRIDE' = 'Without-Water' from acid. Acid minus water gives acid anhydride.
Conceptual Metaphor
A 'dehydrated acid' waiting to regain water and become active again.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'ангидрид кислоты' (correct) and 'кислотный ангидрид' (also correct, but word order differs).
- Avoid literal reverse translation 'ангидридная кислота' – incorrect.
Common Mistakes
- Mispronouncing 'anhydride' as /ænˈhɪd.rɪd/ (should be /ænˈhaɪ.draɪd/).
- Using 'acid anhydride' to refer to any dehydrating agent (e.g., sulphuric acid is not an acid anhydride in this sense).
- Confusing with 'base anhydride' (metal oxides).
Practice
Quiz
What is the primary characteristic reaction of an acid anhydride?
FAQ
Frequently Asked Questions
No. 'Anhydrous acid' refers to a pure acid without water, while 'acid anhydride' is a different compound formed by removing water from two acid molecules.
Acetic anhydride is used industrially to make aspirin and cellulose acetate for photographic film.
They are excellent acylating agents, used to transfer an acyl group to alcohols, amines, or other nucleophiles in synthesis.
Yes, in inorganic chemistry. CO2 is the anhydride of carbonic acid (H2CO3), as it reacts with water to form it.