Thermal Degradation of Aminosilicone Carbamates

Abstract

The major thermal degradation pathway seen with 1,5-bis(3-aminopropyl)-1,1,3,3,5,5-hexamethyltrisiloxane/ triethylene glycol (GAP-1/TEG) is the formation of a urea-containing compound. Degradation is increased at higher temperatures, longer reaction times, higher CO 2 concentrations (in the form of carbamate loading), and low water levels. A judicious choice of operating conditions can significantly decrease urea byproduct formation. Reducing the desorption temperature from 140 to 100 °C and adding 5 wt % water to the 60:40 mixture of GAP-1/TEG resulted in a 500-fold reduction in amine loss after 4 days in a CO 2 -rich environment. After 56 days of continuous heating under the same conditions, ∼87% original GAP-1 was retained at 100 °C compared to only ∼20% at 140 °C. The urea byproduct appears to be the only major degradation pathway under these conditions, with 100% of the mass balance accounted for by the urea and amine components.

Carbon Dioxide Capture Chemistry of Amino Acid Functionalized Metal–Organic Frameworks in Humid Flue Gas

“…The carbon dioxide capture problem is of paramount societal importance. , Although aqueous amine solutions are currently being used to capture CO 2 , they require significant energy input because of the high heat capacity of water and suffer from loss of amines. − Porous solid-state materials are being studied for their potential in offering a platform for mounting amines and foregoing the heat requirement of aqueous solutions. − In this regard, materials such as carbon, , zeolites, silica, − resins, , covalent organic frameworks, and metal–organic frameworks (MOFs) − are being investigated (as summarized in Table ; see Table S1 in the Supporting Information for a more detailed comparison). ,,,− At present, they all fall short of meeting the stringent performance requirements: high uptake capacity, high selectivity, low regeneration energy, fast kinetics, and long cycling lifetime. , We believe that to solve the CO 2 problem, significant efforts are required in understanding the CO 2 chemistry in the pores of such materials and in using this knowledge to build viable structures.…”

Carbon Dioxide Capture Chemistry of Amino Acid Functionalized Metal-Organic Frameworks in Humid Flue Gas

“…[7][8][9] In this regard, materials such as carbon, 7,10 zeolites, 11 silica, [12][13][14][15] resins, 16,17 covalent organic frameworks, 18 and metal-organic frameworks (MOFs), [19][20][21][22][23] are being investigated [as summarized in Table 1, see Table S1 in the Supporting Information (SI) for more detailed comparison]. 7,10,19,[24][25][26][27][28] At present, they all fall short of meeting the stringent performance requirements: high uptake capacity, high selectivity, low regeneration energy, fast kinetics, and long cycling lifetime. 29,30 We believe that in order to solve the CO2 problem, significant efforts are required in understanding the CO2 chemistry in the pores of such materials and in using this knowledge to build viable structures.…”