Bis (2-ethylhexyl) terephthalate

Structural formula
Simplified structural formula - mixture of three stereoisomers
General
Surname	Bis (2-ethylhexyl) terephthalate
other names	1,4-Benzene dicarboxylic acid bis (2-ethylhexyl) ester Dioctyl terephthalate DOTP DEHT DEHTP
Molecular formula	C 24 H 38 O 4
Brief description	colorless liquid
External identifiers / databases
CAS number 6422-86-2 EC number 229-176-9 ECHA InfoCard 100.026.524 PubChem 22932 Wikidata Q5279087
properties
Molar mass	390.59 g mol −1
Physical state	liquid
density	0.986 g cm −3
Melting point	<−67.2 ° C (glass transition temperature) −48 ° C (other sources)
boiling point	400 ° C
Vapor pressure	1 hPa (217 ° C)
solubility	practically insoluble in water (0.4 mg l −1 at 22.5 ° C)
Refractive index	1.49 (20 ° C)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	> 3.2 g kg −1 ( LD 50 ,  rat ,  oral ) > 20 g · kg -1 ( LD 50 ,  guinea pig , skin )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Bis (2-ethylhexyl) terephthalate is a mixture of three isomeric chemical compounds from the group of carboxylic acid esters of terephthalic acid :

• ( R , R ) -form,
• ( S , S ) form and the diastereomeric
• meso shape.

Extraction and presentation

Bis (2-ethylhexyl) terephthalate (DEHTP) can be obtained by transesterification of dimethyl terephthalate with 2-ethylhexanol . In 2002 more than 25,000 t were produced worldwide.

${\displaystyle \mathrm {C_{6}H_{4}(CO)_{2}(OCH_{3})_{2}+2\ C_{8}H_{17}OH\longrightarrow C_{6}H_{4}(CO_{2}C_{8}H_{17})_{2}+2\ CH_{3}OH} }$

properties

Bis (2-ethylhexyl) terephthalate is a flammable, hardly ignitable, colorless liquid that is practically insoluble in water.

use

Bis (2-ethylhexyl) terephthalate is used as a plasticizer in plastics. In particular as a substitute for bis (2-ethylhexyl) phthalate and diisononyl phthalate , for example for PVC in the food sector, cellulose acetate butyrate, cellulose nitrate , polymethyl methacrylate , polystyrene , polyvinyl butyral .

Exposure in the population

In the US – American NHANES – Study (National Health and Nutrition Examination Survey), carried out from 2015 to 2016, the metabolites of DEHTP could be reliably detected using the coupling of HPLC with mass spectrometry in 2970 urine samples after adequate sample preparation . A significantly higher exposure could be measured in the samples of the female study participants.

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on bis (2-ethylhexyl) terephthalate in the GESTIS substance database of the IFA , accessed on February 28, 2017(JavaScript required) .
2. ↑ ^{a b c} Entry on bis (2-ethylhexyl) terephthalate in the Hazardous Substances Data Bank , accessed on February 27, 2016.
3. ↑ ^{a b} Data sheet Dioctyl terephthalate, ≥96% from Sigma-Aldrich , accessed on February 27, 2016 ( PDF ).
4. ↑ Victor O. Sheftel: Indirect Food Additives and Polymers Migration and Toxicology . CRC Press, 2000, ISBN 978-1-56670-499-1 , pp. 1288 ( limited preview in Google Book Search).
5. ↑ Britt E. Erickson: Regulators And Retailers Raise Pressure On Phthalates , Chemical & Engineering News 93 (25), 2015, pp. 11-15.
6. ^ Gary M. Rand: Fundamentals Of Aquatic Toxicology Effects, Environmental Fate And Risk Assessment . CRC Press, 1995, ISBN 978-1-56032-090-6 , pp. 690 ( limited preview in Google Book search).
7. ↑ Silva MJ, Wong LY, Samandar E, Preau JL Jr, Jia LT, Calafat AM: Exposure to di-2-ethylhexyl terephthalate in the US general population from the 2015-2016 National Health and Nutrition Examination Survey. , Environ Int. 2019 Feb; 123: 141-147, PMID 30529838