Xn:Harmful;
629-73-2Relevant academic research and scientific papers
LA PHOTOLYSE DES ACIDES ET DES ESTERS
Wolff, Genevieve,Ourisson, Guy
, p. 1441 - 1442 (1981)
Irradiation of saturated acids or esters below 220 nm leads to a Norrish-II cleavage or an 1,2-elimination in preparatively useful yields; this is illustrated by several efficient degradations, including that of the side-chain of bile acids.
Linear long-chain α-olefins from hydrodeoxygenation of methyl palmitate over copper phyllosilicate catalysts
Choojun, Kittisak,Huang, Ai-Lin,Lin, Yu-Chuan,Poo-arporn, Yingyot,Prasanseang, Warot,Sooknoi, Tawan
, (2022/03/01)
Copper phyllosilicate (CuPS) was used as a bifunctional catalyst for hydrodeoxygenation of methyl palmitate (MP) to produce long-chain α-olefins without the loss of carbon backbone. The CuPS catalysts were prepared by ammonia evaporation-hydrothermal method. The crystal structure, surface area, reducibility, Cu dispersion, Cu particle size and acidity of the catalysts were examined by XRD, BET, H2-TPR, TEM, NH3-TPD and Py-IR. The existence of Cu2+ species (octahedral (Oh)/square planar (Sq)), Cu+ and Cu0 upon calcination/reduction was investigated by in situ TR-XANES. The Cu dispersion was related to the Cu+ fraction in CuPS, while Br?nsted acid sites (BAS) depends on Cu0 particles. The MP conversion to 1-hexadecene proceeds via hydrogenation-dehydration promoted by the synergy of Cu0 surface and Br?nsted acid sites at the interface. The α-olefin selectivity depends on a balance between Cu+ and Cu loading. The 20CuPS possessing 10% Cu+ fraction, provides a high conversion of 72% with 45% α-olefin selectivity.
Norrish type II reactions of acyl azolium salts
Hopkinson, Matthew N.,Mavroskoufis, Andreas,Rieck, Arielle
, (2021/10/25)
The photochemical reactivity of acyl azolium salts derived from aliphatic carboxylic acids has been investigated. These species, which serve as models for intermediates generated in N-heterocyclic carbene (NHC) organocatalysis, undergo Norrish type II elimination reactions under irradiation with UVA light in analogy to structurally related aromatic ketones. Moreover, efficient Norrish-Yang cyclization was observed from an adamantyl-substituted derivative. These results further demonstrate the ability of NHCs to influence the absorption properties and photochemical reactivity of carbonyl groups during a catalytic cycle.
Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
supporting information, p. 2273 - 2276 (2021/03/09)
A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
Surfactant-Free Synthesis of Ultrafine Pt Nanoparticles on MoS2Nanosheets as Bifunctional Catalysts for the Hydrodeoxygenation of Bio-Oil
Fan, Xiaobin,Li, Yang,Liang, Junmei,Lin, Qianqian,Peng, Wenchao,Xu, Danyun,Zhang, Fengbao,Zhang, Qicheng
, p. 14710 - 14716 (2020/12/23)
Hydrodeoxygenation (HDO) of bio-oil is a crucial step for improving the bio-fuel quality, but developing highly dispersed Pt-based catalysts with high selectivity for target alkanes remains a great challenge. This study presents a fast surfactant-free method to prepare the MoS2-supported Pt catalyst for HDO. Ultrafine Pt nanoparticles with sizes of 5 nm can be readily grown on chemically exfoliated MoS2 nanosheets (NSs) via the direct microwave-assisted thermal reduction. The obtained Pt NPs/MoS2 composites show excellent catalytic performance in the conversion of palmitic acid, and the best selectivity (also the yield) of hexadecane and pentadecane is 80.56 and 19.43%, respectively.
A hydroxylamine probe for profiling: S-acylated fatty acids on proteins
Schulte-Zweckel, Janine,Dwivedi, Mridula,Brockmeyer, Andreas,Janning, Petra,Winter, Roland,Triola, Gemma
, p. 11183 - 11186 (2019/09/30)
Reversible S-palmitoylation is a key regulatory mechanism of protein function and localization. There is increasing evidence that S-acylation is not restricted to palmitate but it includes shorter, longer, and unsaturated fatty acids. However, the diversity of this protein modification has not been fully explored. Herein, we report a chemical probe that combined with MS-based analysis allows the rapid detection and quantification of fatty acids linked to proteins. We have used this approach to profile the S-acylome and to show that the oncogene N-Ras is heterogeneously acylated with palmitate and palmitoleate. Studies on protein distribution in membrane subdomains with semisynthetic proteins revealed that unsaturated N-Ras presents an increased tendency toward clustering and higher insertion kinetic rate constants.
Hexadecane Conversion on an Alumina–Nickel Catalyst
Chesnokov,Chichkan,Paukshtis,Chesalov, Yu. A.,Krasnov
, p. 439 - 445 (2019/09/04)
Abstract: The conversion of hexadecane on a 4% Ni/Al2O3 catalyst in a temperature range of 20–300°C was studied using IR spectroscopy and catalytic methods. It was found that the dehydrogenation of hexadecane occurred at 20–100°C with the subsequent formation of aromatic products, but the rates of these processes were very low. As the reaction temperature was increased to 200°C, the 4% Ni/Al2O3 catalyst exhibited a maximum activity and high selectivity for the formation of 1-hexadecene, and aromatic compounds and cracking products were present in the reaction products. As the reaction temperature was further increased, the catalytic activity significantly decreased. This was due to the fact that polyaromatic deposits gradually accumulated on the catalyst surface in a temperature range of 200–300°C.
Selective Catalytic Hydrogenolysis of Carbon-Carbon σ Bonds in Primary Aliphatic Alcohols over Supported Metals
Di, Lu,Yao, Sikai,Li, Mengru,Wu, Guangjun,Dai, Weili,Wang, Guichang,Li, Landong,Guan, Naijia
, p. 7199 - 7207 (2015/12/11)
The selective scission of chemical bonds is always of great significance in organic chemistry. The cleavage of strong carbon-carbon σ bonds in the unstrained systems remains challenging. Here, we report the selective hydrogenolysis of carbon-carbon σ bonds in primary aliphatic alcohols catalyzed by supported metals under relatively mild conditions. In the case of 1-hexadecanol hydrogenolysis over Ru/TiO2 as a model reaction system, the selective scission of carbon-carbon bonds over carbon-oxygen bonds is observed, resulting in n-pentadecane as the dominant product with a small quantity of n-hexadecane. Theoretical calculations reveal that the 1-hexadecanol hydrogenolysis on flat Ru (0001) undergoes two parallel pathways: i.e. carbon-carbon bond scission to produce n-pentadecane and carbon-oxygen bond scission to produce n-hexadecane. The removal of adsorbed CO on a flat Ru (0001) surface is a crucial step for the 1-hexadecanol hydrogenolysis. It contributes to the largest energy barrier in n-pentadecane production and also retards the rate for n-hexadecane production by covering the active Ru (0001) surface. The knowledge presented in this work has significance not just for a fundamental understanding of strong carbon-carbon σ bond scission but also for practical biomass conversion to fuels and chemical feedstocks.
Photobiocatalytic decarboxylation for olefin synthesis
Zachos, Ioannis,Ga?meyer, Sarah Katharina,Bauer, Daniel,Sieber, Volker,Hollmann, Frank,Kourist, Robert
supporting information, p. 1918 - 1921 (2015/02/05)
Here, we describe the combination of OleTJE with a light-driven in situ H2O2-generation system for the selective and quantitative conversion of fatty acids into terminal alkenes. The photobiocatalytic system shows clear advantages regarding enzyme activity and yield, resulting in a simple and efficient system for fatty acid decarboxylation.
Photon can tremendously accelerate the alkyl iodides' elimination in water
Liu, Wenbo,Li, Chao-Jun
supporting information, p. 1699 - 1702 (2015/03/14)
Elimination of the alkyl halides in water is very difficult due to the heterogeneous nature and the limitation of base strength. We discovered that ultra-violet (UV) light can enhance the elimination rate of alkyl iodides, including primary, secondary, and tertiary iodides in water dramatically for the first time. We propose a tandem radical-carbocation reaction mechanism to rationalize this special property of alkyl iodides.
