7642-10-6Relevant academic research and scientific papers
Graphite oxide activated zeolite NaY: Applications in alcohol dehydration
Todd, Alexander D.,Bielawski, Christopher W.
, p. 135 - 139 (2013/03/29)
A mixture of graphite oxide (GO) and the zeolite NaY (Si/Al = 5.1) was used to dehydrate various alcohols to their respective olefinic products. Using conditions optimized for 4-heptanol (15 wt% GO-NaY (1 : 1 wt/wt), 150°C, 30 min), a series of secondary and tertiary aliphatic alcohols were cleanly dehydrated in moderate to excellent conversions (27.5-97.2%). Several primary alcohols were also dehydrated, although higher catalyst loadings (200 wt% GO-NaY (1 : 1) and longer reaction times (3 h) were required. The enhanced dehydration activity was attributed to the ability of GO to convert NaY to an acidic form and without the need for ammonium cation exchange and/or high temperature calcination. The Royal Society of Chemistry 2013.
Pt/[Fe]ZSM-5 modified by Na and Cs cations: An active and selective catalyst for dehydrogenation of n-alkanes to n-alkenes
Li, Xuebing,Iglesia, Enrique
, p. 594 - 596 (2008/09/21)
Pt clusters within [Fe]ZSM-5 channels provide active and stable sites for the selective catalytic dehydrogenation of n-alkanes to n-alkenes. Cs and Na cations titrate acid sites and inhibit skeletal isomerization and cracking side reactions. The Royal Soc
Photolysis of dipropyldiazirine and trapping of dipropylcarbene with piperidine
Tae, Eunju Lee,Platz, Matthew S.
, p. 2875 - 2878 (2007/10/03)
Photolysis (350 nm) of dipropyldiazirine in methylene chloride at 4°C produces a mixture of E and Z 3-heptene in 81% yield in an E/Z ratio of 1.8. Tetrapropylazine was formed in less than 5% yield. Photolysis of dipropyldiazirine in the presence of piperidine leads to the formation of a carbene-amine adduct. In the presence of 0.06 M piperidine the yield of adduct is 48%, the yield of E and Z 3-heptene is 47% and the E/Z ratio of 3- heptenes is 1.1. The results show that heptene is formed by three pathways. One pathway involves dipropylcarbene formed directly from the diazirine, the other pathways are attributed to ionic and photochemical reactions of 4- diazoheptane and to the excited state of the diazirine precursor. Dipropylcarbene can be easily intercepted with a simple trap. The yield of this process is limited by the efficiency with which the precursor forms the carbene.
Chemistry and Kinetics of Dipropylcarbene in Solution
Tae, Eunju Lee,Zhu, Zhendong,Platz, Matthew S.,Pezacki, John Paul,Warkentin, John
, p. 5336 - 5342 (2007/10/03)
The photochemistry of 2-methoxy-2-methyl-5,5-dipropyl-Δ3-1,3,4-oxadiazoline (1a) and 2,2-dimethoxy-5,5-dipropyl-Δ3-1,3,4-oxadiazoline (1b) was investigated. Photolysis (300 nm) of these compounds in solution leads to fragmentation to 4-diazoheptane (major), which slowly forms the corresponding azine. Fragmentation to form 4-heptanone is also observed. Yields of 4-diazoheptane in CH2Cl2 are much larger than those in pentane. 4-Diazoheptane can be trapped with 1-pentene to form a pyrazoline or with methanol to form 4-methoxyheptane. The pyrazoline can be decomposed photochemically to form 1,1,2-tripropylcyclopropane. In solution, 4-diazoheptane is inefficiently photolyzed to dipropylcarbene (DPC), which can be trapped with piperidine or with pyridine in laser flash photolysis experiments. Analysis of the piperidine and pyridine data indicates that the lifetime of DPC in cyclohexane, methylene chloride, or Freon-113 (CF2ClCFCl2) solution at ambient temperature is controlled by 1,2 hydrogen migration to form Z- and E-3-heptene. The lifetime deduced under these conditions is ≈300 ps, which is about 20-fold shorter than that of dimethylcarbene in perfluorohexane at ambient temperature. Upon photolysis (254 nm) of oxadiazoline 1a in argon, 4-diazoheptane and 1-methoxydiazoethane are formed. These diazo compounds undergo subsequent photolysis that revealed the formation of methoxy(methyl)carbene and E- and Z-3-heptene. It was not possible to detect DPC in argon at 14 K.
A convenient synthesis of episulfides and their conversion into alkenes
Dybowski, Piotr,Skowrońska, Aleksandra
, p. 1134 - 1136 (2007/10/03)
A convenient and stereoselective synthesis of episulfides based on the reaction of readily available S-(β-oxoalkyl) thiophosphate with sodium borohydride and their conversion into alkenes is described.
A NEW STRATEGY FOR THE STEREOSELECTIVE SYNTHESIS OF OLEFINS
Dybowski, Piotr,Skowronska, Aleksandra
, p. 4385 - 4388 (2007/10/02)
Highly stereoselective conversion of ketones into (Z)-olefins, via intermediate S-(β-oxoalkyl)thiophosphates and their seleno analogues is described.
Protium-deuterium exchange of cyclic and acyclic alkanens in dilute acid medium at elevated temperatures
Werstiuk, Nick Henry,Timmins, George
, p. 530 - 533 (2007/10/02)
A modification of the high temperature - dilute acid (HTDA) method for deuterium labelling of aromatic compounds has been applied to the H-D exchange of a number of cyclic and acyclic alkenes.Cyclopentene, cyclohexene, cyclododecene, and tetramethylethylene have been completely exchanged in excellent yield. 1-Methylcyclopentene and 1-methylcyclohexene have also been perdeuterated and cycloheptene and cyclooctene partially labelled but require spinning band distillation or preparative glpc for separation from rearrangement products.A variety of C5-C8 acyclic alkeneshave also been treated under HTDA conditions.
THE EFFECT OF ORGANIC SOLVENTS ON THE REACTION OF HIGHER 1-ALKENES WITH PALLADIUM DICHLORIDE IN AQUEOUS SOLUTION
Kaszonyi, Alexander,Vojtko, Jan,Hrusovsky, Mikulas
, p. 2128 - 2139 (2007/10/02)
It was found that hydrophilic organic solvent, added to aqueous PdCl2 solution to increase the solubility of alkene, affects both parallel processes taking place during the reaction of 1-alkenes with PdCl2, i.e. the isomerisation of 1-alkene to internal n-alkenes and the oxidation of alkenes to carbonyl compounds; the solvent can facilitate either both processes (alcohols) or only one of the processes (acetic acid - isomerisation, N,N-dimethylformamide - oxidation), eventually it can retard both or one of processes (acetonitrile - oxidation, dioxane - isomerisation, dimethyl sulphoxide - isomerisation and oxidation).On using 2-methoxyethanol as the solvent, the oxidation of 1-octene can be correlated by the same rate equation as the oxidation of styrene or ethylene.
Photochemistry of Thietane Excited to Its Second Excited Electronic Singlet State
Dorer, F.H.,Okazaki, M. E.,Salomon, K. E.
, p. 2671 - 2676 (2007/10/02)
Thietane, excited to its S2 state, undergoes fragmentation to ethylene and thioformaldehyde by one channel and a competing reaction, unique to the S2 state, is decomposition to cyclopropane and sulfur atoms.Previous work on the S2 state of thietane has been extended to include a more detailed examination of the spectra and energy partitioning in the cyclopropane formimg reaction; and, by photolizing cis- and trans-3-ethyl-2-propylthietane, we have followed the stereochemical course of both reaction channels.The products of both reactions largely retain the stereochemistry of the reactant.Energy partitioning indicates that S(3P) is the atomic fragment when cyclopropane is produced.A mechanism which accomodates the experimental results assumes that, once excited to its 1B2 electronic state, intersystem crossing to the 3B2 state competes with C-S bond rupture that forms the 1,4-diradical intermediate which yields the ring cleavage products.The 3B2 state decomposes to cyclopropane and S(3P) by a mechanism that likely involves a singlet trimethylene diradical as an intermediate.
