2-phenylphenol

Structural formula
General
Surname	2-phenylphenol
other names	E 231; Biphenyl-2-ol; 2-hydroxybiphenyl; Orthophenylphenol; O-PHENYLPHENOL ( INCI ) ;
Molecular formula	C 12 H 10 O
Brief description	white to pink solid with a phenolic odor
External identifiers / databases
EC number	201-993-5
ECHA InfoCard	100.001.812
PubChem	7017
Wikidata	Q209467
properties
Molar mass	170.21 g mol −1
Physical state	firmly
density	1.26 g cm −3
Melting point	59 ° C
boiling point	286 ° C
Vapor pressure	40 Pa (20 ° C)
pK s value	10.01 (25 ° C)
solubility	very poorly in water (0.7 g l −1 at 20 ° C), soluble in ethanol , acetone and benzene , very soluble in diethyl ether and pyridine
safety instructions
H and P phrases	H: 335-315-319-400
	P: 273-305 + 351 + 338-302 + 352
MAK	5 mg m −3 (measured as the inhalable aerosol fraction)
Toxicological data	2000 mg kg −1 ( LD 50 , rat , oral ) ; 5.24 mg l −1 ( LC 50 , fish , 96 h, median value ) ; 2.1 mg l −1 ( EC 50 , crustaceans , 48 h, median value ) ; 5 mg l −1 ( EC 50 , Alga , 72 h ) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2-phenylphenol (also orthophenylphenol ) is an organic compound . It consists of a phenol with a phenyl radical in the ortho position .

Extraction and presentation

2-Phenylphenol was previously obtained from the heavy oils of coal tar that were distilled over.

The industrial standard synthesis starts from cyclohexanone , which reacts in an aldol addition to form the dimer. When heated in the presence of carboxylic acid salts of transition metals, such as. B. vanadium stearate, splits off the addition product water and forms an isomer mixture of two aldol condensation products (95% yield).

Their dehydration on a platinum contact at high temperatures (270 ° C) produces 2-phenylphenol in 85% yield.

properties

2-Phenylphenol is a colorless, crystalline solid with only a weak odor. It is only very sparingly soluble in water, but readily soluble in alcohols, e.g. B. methanol and ethanol, as well as in acetonitrile and pyridine . The flash point is 138 ° C, the ignition temperature > 520 ° C.

In dilute sodium hydroxide solution , OPP is very soluble with the formation of sodium 2-phenylphenolate. Because of its extreme solubility in water (1,200 g / l), only the sodium salt is used in aqueous preparations.

use

2-phenylphenol is provided as a food additive E231 (or sodium - salt as E232) for the preservation of citrus fruit with a limit / kg approved by 12 mg. The limit value that applies to other fruit and vegetables is exceeded by a factor of 50.

o -Phenylphenol is effective against bacteria, yeasts, fungi and enveloped viruses and is used (mostly in combination with other disinfectants ) for surface disinfection, especially in hospitals and nursing homes.

The Scientific Committee on Consumer Safety (SCCS) of the European Commission recommends a maximum concentration of 0.2% OPP in (washable) cosmetics.

Also for the preservation of aqueous preparations such as B. in adhesives, concrete additives and pigment suspensions, biphenyl-2-ol is used.

As a functional biphenyl , biphenyl-2-ol is a starting material for the flame retardant DOPO . It also serves as a dyeing accelerator in the dyeing of synthetic fibers.

Legal status

According to Directive 2003/114 / EC, 2-phenylphenol (orthophenylphenol and sodium orthophenylphenol) will in future no longer be a food additive, but will be subject to the statutory regulations on plant protection products. To do this, however, the preservative must first be approved as a pesticide. Since sodium orthophenylphenolate can continue to be used to treat the surfaces of citrus fruits and consumers must be informed about this, there will also be labeling of the substance in the future. However, the legal regulations for this marking have not yet been issued by the European Commission or by the member states of the European Union. Until this legal loophole is closed, 2-phenylphenol will remain approved as food additive E231 and E232 and will be labeled accordingly.

Web links

International Chemical Safety Card (ICSC) for o-phenylphenol at the National Institute for Occupational Safety and Health (NIOSH).

Individual evidence

↑ Entry on O-PHENYLPHENOL in the CosIng database of the EU Commission, accessed on March 11, 2020.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Entry on 2-phenylphenol in the GESTIS substance database of the IFA , accessed on December 16, 2019(JavaScript required) .
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dissociation Constants of Organic Acids and Bases, pp. 8-50.
^ William M. Haynes: CRC Handbook of Chemistry and Physics, 97th Edition . CRC Press, Boca Raton, FL, USA 2017, ISBN 978-1-4987-5429-3 , pp. 3-306 .
↑ Entry on biphenyl-2-ol 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 .
↑ Patent US3980716 : Production of ortho-phenylphenol from cyclohexanone. Applied on April 2, 1973 , published September 14, 1976 , Applicant: Imperial Chemical Industries, Ltd., Inventor: CS Elliott. ‌
↑ ^a ^b ADDENDUM to the scientific opinion on o-phenylphenol, sodium o-phenylphenate and potassium o-phenylphenate (SCCS / 1555/15). In: SCCS / 1597/18. Scientific Committee on Consumer Safety SCCS, February 21, 2018, accessed May 28, 2018 .
↑ ZZulV : Appendix 5 (to Section 5, Paragraph 1 and Section 7) Additives that are approved for preservation or as antioxidants in foods
↑ ECJ: The Court of Justice confirms that the labeling of citrus fruits with the indication of preservatives and other chemical substances used in post-harvest treatment is mandatory In: curia.europa.eu , March 3, 2016, accessed on June 22, 2018.
↑ Guideline for Disinfection and Sterilization in Healthcare Facilities (2008). CDC Centers for Disease Control and Prevention, February 15, 2017, accessed May 28, 2018 .
↑ Directive 2003/114 / EC
↑ additives-online E231 and E232

[CosIng-1] Entry on O-PHENYLPHENOL in the CosIng database of the EU Commission, accessed on March 11, 2020.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Entry on 2-phenylphenol in the GESTIS substance database of the IFA , accessed on December 16, 2019(JavaScript required) .

[CRC90_8_50-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dissociation Constants of Organic Acids and Bases, pp. 8-50.

[4] William M. Haynes: CRC Handbook of Chemistry and Physics, 97th Edition . CRC Press, Boca Raton, FL, USA 2017, ISBN 978-1-4987-5429-3 , pp. 3-306 .

[CLP_100.001.812-5] Entry on biphenyl-2-ol 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 .

[6] Patent US3980716 : Production of ortho-phenylphenol from cyclohexanone. Applied on April 2, 1973 , published September 14, 1976 , Applicant: Imperial Chemical Industries, Ltd., Inventor: CS Elliott. ‌

[SCCS-7] ADDENDUM to the scientific opinion on o-phenylphenol, sodium o-phenylphenate and potassium o-phenylphenate (SCCS / 1555/15). In: SCCS / 1597/18. Scientific Committee on Consumer Safety SCCS, February 21, 2018, accessed May 28, 2018 .

[8] ZZulV : Appendix 5 (to Section 5, Paragraph 1 and Section 7) Additives that are approved for preservation or as antioxidants in foods

[9] ECJ: The Court of Justice confirms that the labeling of citrus fruits with the indication of preservatives and other chemical substances used in post-harvest treatment is mandatory In: curia.europa.eu , March 3, 2016, accessed on June 22, 2018.

[10] Guideline for Disinfection and Sterilization in Healthcare Facilities (2008). CDC Centers for Disease Control and Prevention, February 15, 2017, accessed May 28, 2018 .

[11] Directive 2003/114 / EC

[12] tives-online E231 and E232