Tricresyl phosphates

from Wikipedia, the free encyclopedia

Tricresyl phosphates ( TKP , English TCP ) are a group of chemical compounds that occur in 10 different isomeric forms. They are phosphoric acid esters of cresols . Since cresol can exist as ortho , meta or para cresol, the isomers of TKP differ in the position of the methyl group  (-CH 3 ) on the three aromatic rings. You can, for example, as o , o , o tricresyl phosphate, o , o , m tricresyl phosphate, o , o , p tricresyl phosphate, o , m , m tricresyl phosphate, o , m , p tricresyl phosphate, o , p , p - tricresyl phosphate, m , m , m -Trikresylphosphat, m , m , p -Trikresylphosphat, m , p , p -Trikresylphosphat or p , p , p present -Trikresylphosphat.

Substances

Tricresyl phosphates
Surname Tricresyl phosphate
(mixture of isomers)
o, o, o-tricresyl phosphate m, m, m -tricresyl phosphate p, p, p -tricresyl phosphate
other names
Tolyl phosphate, TKP, TCP (English)
Tris (methylphenyl) phosphate
Structural formula Structural formula of o, o, o-tricresyl phosphate Structural formula of m, m, m-tricresyl phosphate Structural formula of p, p, p-tricresyl phosphate
CAS number 1330-78-5 78-30-8 563-04-2 78-32-0
ECHA ID 100.014.136 100.001.003 100.008.402 100.001.005
EC number 215-548-8 201-103-5 209-241-8 201-105-6
PubChem 6527 11232 6529
Molecular formula C 21 H 21 O 4 P
Molar mass 368.4 g mol −1
Physical state liquid firmly firmly
Brief description odorless, colorless, oily liquid
Melting point −33 degrees Celsius ° C 11 ° C 25-26 ° C 77 ° C
boiling point 410 ° C 260 ° C 410 ° C
density 1.165 g cm −3 1.18 g cm −3 (20 ° C) 1.16 g cm −3 (20 ° C) 1.16 g cm −3 (20 ° C)
Solubility
in water
practically insoluble practically insoluble practically insoluble (3.4 mg l −1 , 20 ° C)
Flash point 238 ° C 210 ° C 210 ° C
Ignition temperature 385 ° C
GHS
labeling
08 - Dangerous to health 09 - Dangerous for the environment
Caution
from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
08 - Dangerous to health 09 - Dangerous for the environment
danger
from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
07 - Warning 09 - Dangerous for the environment
Caution
from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
07 - Warning 09 - Dangerous for the environment
Caution
H and P phrases 361-410 370-411 302-312-411 302-312-411
no EUH phrases no EUH phrases no EUH phrases no EUH phrases
273-281-501 ? ? ?
Tox data 1160 mg kg −1 ( LD 50ratoral )
MAK Switzerland: 0.1 mg m −3 ( inhalable dust )
WGK 2

If all three methyl groups are attached in the same way, the terms tri- x tolyl phosphate or x- tricresyl phosphate ( x = o , m , p ) are also used. As tricresyl phosphate i. e. S. is generally understood to be a mixture of isomers of the various forms. The physical and physiological properties of the substance differ depending on the isomer mixture present. o -Tricresyl phosphate and other ortho isomers are toxic and inhibit the enzyme cholinesterase .

Extraction and presentation

Tricresyl phosphates can be obtained by reacting cresols with phosphorus oxychloride :

OPCl 3 + 3 HOC 6 H 4 CH 3 → OP (OC 6 H 4 CH 3 ) 3 + 3 HCl

In alkaline media they are converted to cresols and dicresyl phosphates by hydrolysis . Example for caustic soda :

OP (OC 6 H 4 CH 3 ) 3 + NaOH → + HOC 6 H 4 CH 3 + NaO 2 P (OC 6 H 4 CH 3 ) 2

use

Tricresyl phosphates were used as flame retardants and as plasticizers for PVC , nitrocellulose , acrylates , and varnish . They were also used as an additive in lubricants , hydraulic fluids and other technical oils, and as a petrol additive (as an anti-prepreg agent). Tricresyl phosphates protect the engine from glow ignition and the formation of lead residues in the combustion chamber. However, they are no longer used because of their toxicity. An exception to this is the use as an additive for oils (up to 5% proportion) for aircraft engines and jet engines, where they are still in use today. According to an EASA study published in March 2017, the oils analyzed contain TCP, but no toxic orthotricresyl phosphate isomers were detected. According to the study, neuroactive substances are present in the oils after pyrolysis, but in such a low concentration that they cannot cause damage to a healthy lung. In a second study, small amounts of tricresyl phosphate concentrations in the nanogram range per cubic meter were occasionally measured on 69 scheduled flights with eight different aircraft and engine types, but never orthotricresyl phosphate.

Other applications are the use of tricresyl phosphates as coolants , solvents , intermediate products in chemical syntheses and absorbents (washing liquid, e.g. for phenol ).

safety instructions

The o, o, o -isomer - and thus the isomer - is a neurotoxin ( neurotoxic ), since the enzyme acetylcholinesterase inhibiting ( cholinesterase inhibitor ). Health problems can often be observed when poisoning with these substances. On the one hand, vomiting, abdominal pain and diarrhea can occur, characteristically delayed, and on the other hand long-term neurological symptoms such as paralysis, dizziness, headache, signs of fatigue, palpitations, shortness of breath, limb and muscle pain. In the case of passengers, flight attendants and pilots, cases of poisoning are known in which it is assumed that TKP has been poisoned, since the bleed air of aircraft can be contaminated with TKP in the event of incidents.

The consumption of torpedo oils mixed with TKP due to the then prevailing food shortage resulted in poisoning in Eckernförde in 1941/42 (around 70 cases) and 1949, as well as in Kiel in 1944/45 (" Eckernförde disease "). The same happened in 1940 in Ramiswil in the Swiss canton of Solothurn (around 85 cases) and in the canton of Schwyz (17 cases) by Swiss soldiers and civilians caused by the accidental use of machine gun cooling oils with TKP. The victims became known as oil soldiers .

Individual evidence

  1. a b c d e f g h i j Entry on o, o, o-tricresyl phosphate in the GESTIS substance database of the IFA , accessed on December 26, 2019 (JavaScript required)
  2. a b c d e f g h Entry on m, m, m-tricresyl phosphate in the GESTIS substance database of the IFA , accessed on December 26, 2019(JavaScript required) .
  3. a b c d e f g Entry on p, p, p-tricresyl phosphate in the GESTIS substance database of the IFA , accessed on December 26, 2019 (JavaScript required)
  4. Template: CL Inventory / not harmonized There is not yet a harmonized classification for this substance . A labeling of tris (methylphenyl) phosphate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 10, 2016, is reproduced from a self-classification by the distributor .
  5. Tritolyl phosphate data sheet from Sigma-Aldrich , accessed on August 10, 2016 ( PDF ).
  6. Entry on Tri-o-tolyl phosphate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 10, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  7. Entry on Tri-m-tolyl phosphate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 10, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  8. Entry on Tri-p-tolyl phosphate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 10, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  9. Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values , accessed on November 2, 2015.
  10. Saxon State Office for Environment and Geology : Industry-related information sheets. 4: Petrol stations / tank farms
  11. Bundesverband der Deutschen Luftverkehrswirtschaft: Status report: Quality of cabin air in commercial aircraft | March 2017 ( Memento of the original from August 5, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed on August 5, 2017 @1@ 2Template: Webachiv / IABot / www.bdl.aero
  12. Entry on tricresyl phosphate. In: Römpp Online . Georg Thieme Verlag, accessed on December 5, 2013.
  13. Environmental Health Criteria (EHC) for Tricresyl Phosphate , accessed November 29, 2014.
  14. HM Bolt, Z. Myslak: Toxikologie von Arbeitsstoffe , in Basics of Occupational Medicine , Stuttgart, 1985, Verlag W. Kohlhammer, pp. 279–361.
  15. Carsten Schabosky: Poisonous chemical in airplanes. ( Memento from February 12, 2009 in the Internet Archive ) Report at WDR2 from February 3, 2009 (archive version).
  16. Information about Aerotoxic Syndrome. The Aerotoxic Association, accessed December 5, 2013.
  17. Contaminated cabin air on board commercial aircraft (PDF; 63 kB). Answer of the Federal Government to the minor question from MPs Winfried Hermann, Peter Hettlich, Cornelia Behm, other MPs and the Alliance 90 / THE GREENS parliamentary group, printed matter 16/12023, March 5, 2009.

Web links