2-hydroxyethyl acrylate

Structural formula
General
Surname	2-hydroxyethyl acrylate
other names	Hydroxyethyl acrylate HEA (abbreviated) 2-hydroxyethyl acrylate 2-hydroxyethyl propenoate
Molecular formula	C 5 H 8 O 3
Brief description	colorless liquid with a pungent odor
External identifiers / databases
CAS number 818-61-1 EC number 212-454-9 ECHA InfoCard 100.011.322 PubChem 13165 Wikidata Q27253959
properties
Molar mass	116.1 g mol −1
Physical state	liquid
density	1.106 g cm −3
Melting point	<−60 ° C
boiling point	200.3 ° C
Vapor pressure	0.1 h Pa (21.4 ° C)
solubility	miscible with water
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 302-311-314-317-400 P: 273-280-303 + 361 + 353-304 + 340 + 310-305 + 351 + 338-333 + 313
Toxicological data	548 mg kg −1 ( LD 50 ,  rat ,  oral ) 298 mg kg −1 ( LD 50 ,  rabbit ,  transdermal )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

In 2-hydroxyethyl acrylate (HEA) is an ester of acrylic acid . It contains both a hydroxyl group and an unsaturated double bond . It is generally used as a monomer for different classes of binders and polymers.

Extraction and presentation

2-Hydroxyethyl acrylate can be synthesized from the reaction of acrylic acid with ethylene oxide .

If methacrylic acid is used instead of acrylic acid , 2-hydroxyethyl methacrylate is obtained . If hydroxyethyl acrylate is used instead of hydroxyethyl methacrylate in resins and polymers, softer or more flexible properties are obtained.

properties

As a monomer with two different reactive groups, hydroxyethyl acrylate can be used for different applications. If one wishes to synthesize oligomers, resins or polymers with unsaturated double bonds, a reaction can take place via the hydroxyl group. In contrast, oligomers , resins or polymers can be equipped with hydroxyl groups if a polymerization takes place via the unsaturated double bond.

In the reaction with isocyanates , hydroxyethyl acrylate has an average reactivity, which results on the one hand from the electron-donating effect of the hydrocarbon chains and on the other hand from the better availability for the reaction. This means that a hydroxyl group on a long chain has a much better mobility and can thus meet an isocyanate group more easily. It is more reactive than hydroxypropyl acrylate and less reactive than 4-hydroxybutyl acrylate .

use

Hydroxyethyl acrylate can be incorporated into binders such as polyacrylates via free-radical or ionic polymerization . Since hydroxyethyl acrylate has a free hydroxyl group, it can be used to incorporate hydroxyl groups into resins. These groups are then available for curing reactions with isocyanates or urea resins .

In addition to the possibility of incorporating hydroxyethyl acrylate into resins via the double bond , there is also the possibility of doing this via the hydroxyl group. Example would be this is the reaction of 3 moles of hydroxyethyl acrylate and one mole of HDI - isocyanurate . This results in a urethane acrylate which can be used as a reactive diluent in coatings that can be cured by means of UV radiation .

Individual evidence

1. ↑ ^{a b c d e f g h i j} Entry on 2-hydroxyethyl acrylate in the GESTIS substance database of the IFA , accessed on June 11, 2018(JavaScript required) .
2. ↑ Entry on 2-hydroxyethyl acrylate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on June 11, 2018. Manufacturers or distributors can expand the harmonized classification and labeling .
3. ↑ ^{a b c d e} Baumstark, Roland, Schwalm, Reinhold, Schwartz, Manfred: Acrylate resins . Vincentz Network, Hannover 2014, ISBN 978-3-86630-820-6 .