Adipic acid

Structural formula
General
Surname	Adipic acid
other names	1,6-hexanedioic acid ( IUPAC ) 1,4-butanedicarboxylic acid 1,4-dicarboxyl butane E  355 Acifloctin ADIPIC ACID ( INCI )
Molecular formula	C 6 H 10 O 4
Brief description	colorless and odorless solid
External identifiers / databases
CAS number 124-04-9 EC number 204-673-3 ECHA InfoCard 100.004.250 PubChem 196 Wikidata Q357415
properties
Molar mass	146.14 g mol −1
Physical state	firmly
density	1.37 g cm −3
Melting point	151 ° C
boiling point	approx. 330 ° C
Vapor pressure	9.7 Pa (18.5 ° C)
pK s value	pK s 1 = 4.43 pK s 2 = 5.42
solubility	bad in cold water (15 g l −1 at 20 ° C) good in warm water (161 g l −1 at 60 ° C) very good in hot water (1600 g l −1 at 100 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 319 P: 305 + 351 + 338
Toxicological data	1900 mg kg −1 ( LD 50 ,  mouse ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Adipic acid , also hexanedioic acid , is a dicarboxylic acid . Their esters and salts are called adipates .

properties

Adipic acid, HOOC– (CH ₂ ) ₄ –COOH, forms colorless crystals (monoclinic) that melt at 152 ° C and have a long-lasting, sour taste.

Production and occurrence

Adipic acid is obtained through the oxidation of cyclohexene or cyclohexanol with potassium permanganate or nitric acid; in nature it occurs in significant quantities in sugar beet and beetroot . Alternatively, it can be produced from furfural , in which furfural is decarbonylated via a ZnO-Cr ₂ O ₃ contact . With the furan obtained , an ether cleavage (favored by the diene character) can now be carried out with HCl . After a reaction with sodium cyanide and complete hydrolysis , adipic acid is likewise obtained. In addition, large quantities of adipic acid are also produced by the hydrolysis of adiponitrile .

use

Above all, adipic acid is an intermediate for nylon . This plastic is formed as a condensation product from adipic acid and hexamethylenediamine with elimination of water. The monomeric intermediate hexamethylenediamine adipate is also called the AH salt and results from the first letters of the components. Adipic acid is also used as a precursor for the synthesis of polyester polyols for polyurethane systems and thermoplastic polyurethanes. The main areas of application are elastomers, soft and rigid foams. High-boiling esters of adipic acid, especially diethylhexyl adipate , are used to replace esters of phthalic acid as plasticizers for polyvinyl chloride (PVC).

Adipic acid is approved in the EU as a food additive (E 355) and as such serves as an acidulant , just like its alkali salts sodium adipate (E 356) and potassium adipate (E 357) and is sometimes used as a substitute for the tartaric acid in baking powder and lemonades .

In addition, adipic acid is used as an additive in flue gas desulphurisation in order to increase the separation efficiency of limestone washers by more than 99%. The main task of adipic acid is to provide a pH buffer.

Cyclopentanone can be produced synthetically by heating salts of adipic acid .

Web links

Wiktionary: adipic acid  - explanations of meanings, word origins, synonyms, translations

Individual evidence

1. ↑ Entry on E 355: Adipic acid in the European database on food additives, accessed on June 27, 2020.
2. ↑ Entry on ADIPIC ACID in the CosIng database of the EU Commission, accessed on August 6, 2020.
3. ↑ ^{a b c d e f g h} Entry on adipic acid in the GESTIS substance database of the IFA , accessed on February 19, 2017(JavaScript required) .
4. ↑ ^{a b} CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
5. ↑ OECD : Screening Information Dataset (SIDS) Initial Assessment Report (SIAR) for Adipic acid , accessed on March 6, 2017.
6. ↑ Walther Kern, H. Auterhoff, F. Neuwald, W. Schmid: Hager's Handbook of Pharmaceutical Practice For Pharmacists, Pharmaceutical Manufacturers, Druggists, Doctors and Medical Officers . Springer-Verlag, 2013, ISBN 978-3-642-49759-9 , pp. 369 ( limited preview in Google Book search).
7. ↑ Entry on Adipic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
8. ↑ Entry on adipic acid in the ChemIDplus database of the United States National Library of Medicine (NLM) .
9. ^ CH Mac Gillavry: The crystal structure of adipic acid. In: Recueil des Travaux Chimiques des Pays-Bas. 60, 1941, pp. 605-617, doi : 10.1002 / recl.19410600805 .
10. ↑ Entry on cyclopentanone. In: Römpp Online . Georg Thieme Verlag, accessed December 10, 2014.