Xi:Irritant;
103-11-7Relevant articles and documents
Covalent Adaptable Networks Using β-Amino Esters as Thermally Reversible Building Blocks
Taplan, Christian,Guerre, Marc,Du Prez, Filip E.
, p. 9140 - 9150 (2021)
In this study, β-amino esters, prepared by the aza-Michael addition of an amine to an acrylate moiety, are investigated as building blocks for the formation of dynamic covalent networks. While such amino esters are usually considered as thermally nondynamic adducts, the kinetic model studies presented here show that dynamic covalent exchange occurs via both dynamic aza-Michael reaction and catalyst-free transesterification. This knowledge is transferred to create β-amino ester-based covalent adaptable networks (CANs) with coexisting dissociative and associative covalent dynamic exchange reactions. The ease, robustness, and versatility of this chemistry are demonstrated by using a variety of readily available multifunctional acrylates and amines. The presented CANs are reprocessed via either a dynamic aza-Michael reaction or a catalyst-free transesterification in the presence of hydroxyl moieties. This results in reprocessable, densely cross-linked materials with a glass transition temperature (Tg) ranging from -60 to 90 °C. Moreover, even for the low Tg materials, a high creep resistance was demonstrated at elevated temperatures up to 80 °C. When additional β-hydroxyl group-containing building blocks are applied during the network design, an enhanced neighboring group participation effect allows reprocessing of materials up to 10 times at 150 °C within 30 min while maintaining their material properties.
METHOD FOR PRODUCING UNSATURATED CARBOXYLIC ESTER
-
Paragraph 0064-0072, (2021/01/25)
An object of the present invention is to provide a method for producing an unsaturated carboxylic ester, wherein the risk of polymerization blockage is reduced and the required equipment cost and workload involved are kept low while maintaining a high conversion rate in an esterification reaction of unsaturated carboxylic acid. This object can be achieved by a method for producing an unsaturated carboxylic ester, which includes performing an esterification reaction using a reactor packed with a solid catalyst, wherein unsaturated carboxylic acid and alcohol are continuously fed to the reactor from an inlet thereof to form a fluid of the reaction solution in the reactor, and the vaporized organic solvent is continuously fed to the reactor from the inlet or a part near the inlet of the reactor.
PROCESS FOR PREPARING CARBOXYLIC ACID ESTERS IN THE PRESENCE OF A TITANIUM-CONTAINING CATALYST
-
Page/Page column 16; 17; 18, (2016/04/09)
?The present invention relates to a process for preparing carboxylic acid esters, comprising esterification of a carboxylic acid with an alcohol in the presence of a titanium-containing catalyst selected from compounds of a general formula, Tin(OR)x(OR')xOy, wherein n is an integer from 1 to 4; у is an integer from 0 to 6; x can be the same or different and is an integer from 2 to 8; R is a linear or branched C1-C18alkyl, C3-C18cycloalkyl, R' is aryl optionally comprising an electron-donor substituent; or a mixture thereof, with the proviso that if n is 1, then x is 2 and у is 0; and if n>1, then the compounds comprise at least two alkoxy groups and two aryloxy groups. The present invention also relates to a process for preparing carboxylic acid esters, wherein a compound of general formula (I) or (II), wherein q represents an integer of 1 to 4; Y is independently R or R'; or a mixture thereof, with the proviso that the compounds comprise at least two alkoxy groups and two aryloxy groups, is used as a catalyst. The claimed process allows to reduce the amount of a used catalyst and the time of the process duration, while increasing the conversion rate of initial reagents and the yield of a target product.
