872-05-9Relevant articles and documents
Degradation kinetics and solvent effects of various long-chain quaternary ammonium salts
Kleijwegt, Roel J. T.,Winkenwerder, Wyatt,Baan, Wim,van der Schaaf, John
, p. 16 - 27 (2021/08/30)
Surfactants such as quaternary ammonium salts (QAS) have been in increasing demand, for emerging new applications. Recent attempts at process intensification of their production have disclosed the need for a better understanding of QAS thermal stability. This work aims to determine the degradation kinetics of various QASs and the associated solvent?effects. The degradation kinetics of four methyl carbonate QASs were determined in various polar solvents in stainless steel batch autoclaves. (Formula presented.) H NMR spectrometry was employed for offline analysis of the reaction mixtures. The kinetic parameters were then used to compare the thermal stability of the four compounds in the polar solvents. Water showed no degradation, and methanol (MeOH) was the solvent that provided the second-best stability. Water–MeOH mixtures may provide an overall optimum. Moreover, and longer long-chain substituents increased the degradation?rate. Thermogravimetric analysis was used to obtain the thermal stability in a solid state, that is, solventless environment. Isoconversional analysis showed that no reliable kinetic parameters could be determined. Nevertheless, the data did allow for a comparison of the thermal stability of 14 different QASs. Furthermore, the relative instability of the compounds in the solid state demonstrated the challenges of solventless QAS?production.
ACYCLIC CARBENE LIGAND FOR RUTHENIUM COMPLEX FORMATION, RUTHENIUM COMPLEX CATALYST, AND USE THEREOF
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Paragraph 0124-0130, (2021/05/14)
Provided are a novel acyclic carbene ligand for ruthenium complex formation; a ruthenium complex catalyst using the ligand; a method of using the complex as a catalyst in an ethylene-metathesis ethenolysis reaction; a method of preparing the ruthenium complex catalyst; and a method of preparing a linear alpha-olefin, the method including the step of reacting a linear or cyclic alkene compound in the presence of the ruthenium complex catalyst. The acyclic carbene ligand of the present invention and the ruthenium complex catalyst using the same have high selectivity and turnover number for terminal olefin formation in an ethylene-metathesis ethenolysis reaction, and thus linear α-olefins may be prepared with a high yield.
Influence of the pendant arm in deoxydehydration catalyzed by dioxomolybdenum complexes supported by amine bisphenolate ligands
John, Alex,Lunn, Maiko J.,Silva, Israel,Siu, Timothy C.
supporting information, p. 9933 - 9941 (2020/07/03)
Dioxomolybdenum complexes supported by aminebisphenolate ligands were evaluated for their potential in catalyzing the deoxydehydration (DODH) reaction to establish structure-activity relationships. The nature of the pendant arm in these aminebisphenolate ligands was found to be crucial in determining reactivity in the deoxydehydration of styrene glycol (1-phenyl-1,2-ethanediol) to styrene. Pendant arms bearing strongly coordinating N-based groups such as pyridyl or amino substituents were found to hinder activity while those bearing non-coordinating pendant arms (benzyl) or even weakly coordinating groups (an ether) resulted in up to 6 fold enhancement in catalytic activity. A dioxomolybdenum complex featuring an aminemonophenolate ligand derived from the aminebisphenolate skeleton also resulted in similar yield enhancements. Although aromatic solvents were found to be ideal for performing these catalytic reactions, polar solvents such as N,N-dimethylformamide (DMF) and N,N′-dimethylpropyleneurea (DMPU) were also suitable. The catalyst was found to maintain its structural integrity under the optimized conditions and could be recycled for a second catalytic run without loss of activity. With the activated substrate meso-hydrobenzoin, trans-stilbene was obtained in a 56% yield at 220 °C along with benzaldehyde (71%) suggesting that the diol is a competing reductant under these conditions. This journal is