25085-53-4Relevant articles and documents
Addition of Pentenes to Slowly Reacting Mixtures of Hydrogen and Oxygen at 480 deg C
Baldwin, Roy R.,Bennett, Joan P.,Walker, Raymond W.
, p. 2396 - 2412 (1980)
A detailed analysis has been made of the products formed when 1percent of pent-1-ene and of cis-pent-2-ene are added to slowly reacting mixtures of H2 + O2 in aged boric-acid-coated vessels at 480 deg C.The primary products are formed through four different types of attack on the pentenes of almost equal importance, radical addition of H, OH, and HO2, and H atom abstraction from the pentenes by all three radicals.Penta-1,3-diene is the only C5 diene observed, in marked contrast to an earlier study of pentene oxidation.From measurements of the initial relative yields of penta-1,3-diene and buta-1,3-diene, a value of k2 = 2.1 x 1E6 dm3 mol-1 s-1 at 480 deg C is obtained. This is the first value determined for a reaction of this type and is at least ten times lower than rate constants for the formation of an alkene from an alkyl radical.This decrease is consistent with the considerably lower enthalpy change in reaction (2).Product analysis suggests that H atoms add almost equally at the two positions in pent-2-ene, and in the ratio of 0.65 +/-0.2 for non-terminal/terminal addition in pent-1-ene.In contrast to the behaviour of vibrationally-excited propyl and butyl radicals formed by H atom addition to alkenes, there is no evidence for an enhanced rate of decomposition of the pentyl radicals formed from the pentenes.Conjugate oxirans are formed mainly by HO2 addition to the pentenes, and lower aldehydes mainly by OH addition.
A pronounce approach on the catalytic performance of mesoporous natural silica toward esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols
Said, Abd El-Aziz A.,Abd El-Wahab, Mohamed M. M.,El-Gamal, Nadia O.,Goda, Mohamed N.
, p. 257 - 268 (2021/12/14)
Catalytic esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N2 sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Br?nsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions.
Investigation on the Thermal Cracking and Interaction of Binary Mixture of N-Decane and Cyclohexane
Chen, Xuejiao,Pang, Weiqiang,Wang, Bo,Zhang, Ziduan,Zhou, Lingxiao,Zhu, Quan
, (2022/03/02)
Abstract: The investigation about the thermal cracking performance and interaction of different components in hydrocarbon fuels is of great significance for optimizing the formulation of high-performance hydrocarbon fuels. In this work, thermal cracking of n-decane, cyclohexane and their binary mixture were studied in a tubular reactor under different temperatures and pressures. The gas and liquid products were analyzed in detail with different gas chromatography. The main gas products of pure n-decane and cyclohexane are similar, and there is a certain difference in the main liquid products. For binary mixture, the overall conversion rate and gas yield are lower than their theoretical value. The cracking conversion rate of n-decane in binary mixture is lower than that in pure n-decane, but the opposite change occurs for cyclohexane, and the effect become more obvious as the increase of the reaction pressure. These experimental phenomena can be explained by bond dissociation energy and free radical reaction mechanism. The pressure affects the free radical reaction path, and high pressure is more conducive to bimolecular hydrogen abstraction reaction, which will lead to different product content. A law of interaction between the n-decane and cyclohexane was observed according to the experimental results. [Figure not available: see fulltext.]
