anhydride


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anhydride

(ănhī`drīd, –drĭd) [Gr.,=without water], chemical compound formed by removing water, H2O, from another compound; the anhydride can also react with water to form the original compound. An acid anhydride reacts with water to form an acid; e.g., sulfur trioxide, SO3, reacts with water to form sulfuric acid, H2SO4. A basic anhydride reacts with water to form a base; e.g., calcium oxide, CaO, reacts with water to form calcium hydroxide, Ca(OH)2. Anhydrides of organic acids have many uses. They react with alcohols to form esters; e.g., acetic anhydride, (CH3CO)2O, reacts with ethanol, C2H5OH, to form ethyl acetate, CH3COOC2H5, a useful solvent. They also react with ammonia and primary or secondary amines to form amides. Other important acid anhydrides include maleic anhydride and phthalic anhydride.

anhydride

[an′hī‚drīd]
(chemistry)
A compound formed from an acid by removal of water.

anhydride

1. a compound that has been formed from another compound by dehydration
2. a compound that forms an acid or base when added to water
3. any organic compound containing the group -CO.O.CO- formed by removal of one water molecule from two carboxyl groups
References in periodicals archive ?
In the period of 1998--2002, the country's production of phthalic anhydride (PA) rose 13.8% annually from 74,994 tons in 1998 to 126,000 tons in 2002.
Hydrolyzed styrene-maleic anhydride resins perform as classic anionic polymeric surfactants, combining hydrophobic (styrene) and hydrophilic (carboxylic acid ammonium salt) structural units along a common backbone.
The global phthalic anhydride (PA) market is touted to register a spiraling growth at a significant CAGR over the estimated period (2017-2023).
In March, MFG Chemical has acquired Texas, US-based maleic anhydride derivatives manufacturer Gulf Bayport Chemicals LP.
The seized drugs comprised 1826 Kg Hashish, 40 Kg Opium, 5.5 Kg Amphetamine, 5.5 Kg Heroin, 200 Gram Cocaine and 2520 Liters Acetic Anhydride. ANF Quetta seized mega cache of drugs comprising 1792 Kg Hashish, 2520 liters Acetic Anhydride and 40 Kg Opium in five separate intelligence based operations conducted at Qilla Abdullah, Panjgur, Kech and Quetta.
The operation focuses on identification, monitoring and seizure of consignments of all illicit precursor chemicals especially Acetic Anhydride, Acetyl Chloride, Acetic Acid and Ammonium Chloride, being transported to Afghanistan.
Acetic anhydride is a highly sensitive dual-use chemical which is the main ingredient for manufacturing highly-explosive devices as well as for preparing narcotics substances, especially heroin.
While a small portion of the consignment around 124 plastic cans comprised summer fluid, major part of the consignment around 776 plastics cans contained the dangerous chemical, Acetic Anhydride.
According to details, the acetic anhydride, a main ingredient for preparing narcotics substance as well as use in making highly explosives by the terrorist outfits was shipped from Poland for Peshawar based importer.
Since no one turned up for clearance, physical examination of the consignment was carried out on January 31, in the presence of representatives of terminal operator and independent surveyors, which led to the recovery of huge quantity of dual-use precursor 'Acetic Anhydride' 15,520 liters stuffed in more than 700 plastic cans worth $1.5 million.
Key statement: The present invention relates to a tire having as a member a rubber composition comprising (a) 100 mass parts of a rubber component comprising at least one selected from a natural rubber and a diene base synthetic rubber, (b) silica having a nitrogen-absorbing specific surface area (N2SA) of 180 to 270 m2/g and 0.1 to 10.0 mass parts of (c) a partial ester compound of maleic anhydride and a (poly)oxypropylene derivative described above.