20483-36-7Relevant academic research and scientific papers
Thermal hazard evaluation of cumene hydroperoxide-metal ion mixture using DSC, TAM III, and GC/MS
You, Mei-Li
, (2016/06/15)
Cumene hydroperoxide (CHP) is widely used in chemical processes, mainly as an initiator for the polymerization of acrylonitrile-butadiene-styrene. It is a typical organic peroxide and an explosive substance. It is susceptible to thermal decomposition and is readily affected by contamination; moreover, it has high thermal sensitivity. The reactor tank, transit storage vessel, and pipeline used for manufacturing and transporting this substance are made of metal. Metal containers used in chemical processes can be damaged through aging, wear, erosion, and corrosion; furthermore, the containers might release metal ions. In a metal pipeline, CHP may cause incompatibility reactions because of catalyzed exothermic reactions. This paper discusses and elucidates the potential thermal hazard of a mixture of CHP and an incompatible material's metal ions. Differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III) were employed to preliminarily explore and narrate the thermal hazard at the constant temperature environment. The substance was diluted and analyzed by using a gas chromatography spectrometer (GC) and gas chromatography/mass spectrometer (GC/MS) to determine the effect of thermal cracking and metal ions of CHP. The thermokinetic parameter values obtained from the experiments are discussed; the results can be used for designing an inherently safer process. As a result, the paper finds that the most hazards are in the reaction of CHP with Fe2+. When the metal release is exothermic in advance, the system temperature increases, even leading to uncontrollable levels, and the process may slip out of control.
Synthesis, olfactory evaluation, and determination of the absolute configuration of the 3,4-didehydroionone stereoisomers
Serra, Stefano,Fuganti, Claudio,Brenna, Elisabetta
, p. 1110 - 1122 (2007/10/03)
The synthesis of 3,4-didehydroionone isomers 4, (+)-6, and (-)-6 and of 3,4-didehydro-7,8-dihydroionone isomers 5, (+)-7, and (-)-7 was accomplished starting from commercially available racemic α-ionone (1). Their preparation of the racemic forms 4-7 was first achieved by mean of a number of chemo- and regioselective reactions (Schemes 1 and 2). The enantio- and diastereoselective lipase-mediated kinetic acetylation of 4-hydroxy-γ- ionone (10a/10b) provided 4-hydroxy-γ-ionone (+)-10a/(±)-10b and (+)-4-(acetyloxy)-γ-ionone ((+)12b) (Scheme 3). The latter compounds were used as starting materials to prepare the 3,4-didehydro-γ-ionones (+)- and (-)-6 and the 3,4-didehydro-7,8-dihydro-γ-ionones (+)- and (-)-7 in enantiomer-enriched form. The absolute configuration of (+)-12b was determine by chemical correlation with (+)-(6S)-γ-ionone ((+)-3) and with (-)-(6S)-α-ionone ((-)-1) therefore allowing to assign the (S)-configuration to (+)-6 and (+)-7. Olfactory evaluation of the above described 3,4-didehydroionone isomers shows a significant difference between the enantiomers and regioisomers both in fragrance feature and in detection threshold (Table).
Syntheses of theaspirone and vitispirane via palladium(II)-catalyzed oxaspirocyclization
Nilsson, Ylva I. M.,Aranyos, Attila,Andersson, Pher G.,Baeckvall, Jan-E.,Parrain, Jean-Luc,Ploteau, Christelle,Quintard, Jean-Paul
, p. 1825 - 1829 (2007/10/03)
Total syntheses of theaspirone (A and B) and vitispirane (A and B) are described. The key step in the syntheses is the palladium(II)-catalyzed intramolecular oxaspirocyclization of diene alcohol 4 to either vitispirane or the allylic alcohol 9. The outcome of the oxaspirocyclization is very much dependent on the solvent employed. In water-acetic acid (4:1) a 1:1 mixture of the diastereomeric alcohols 9A and 9B was exclusively formed. In water with 8 equiv of a strong non-nucleophilic acid, vitispiranes A and B (1:1) were obtained. An alternative procedure to obtain vitispirane with the use of LiCl and K2CO3 is described. In the latter reaction vitispirane B is formed preferentially. This result is explained by an equilibrium between the two possible π-allyl complexes 5A and 5B, the kinetically favored 5B being transformed into vitispirane 3B before isomerization to 5A occurs.
Palladium-catalyzed oxaspirocyclizations
Andersson,Nilsson,Backvall
, p. 559 - 572 (2007/10/02)
Palladium-catalyzed oxidation of 1-(3-hydroxyalkyl) and 1-(4- hydroxyalkyl)-1,3-cycloalkadienes results in a stereocontrolled oxaspirocyclization. The reaction proceed via a spirocyclic (π- allyl)palladium intermediate, which is attacked by an acetate or a chloride nucleophile leading to an overall 1,4-addition across the diene. The intermediate (π-allyl) palladium complex was independently prepared and characterized. The stereochemistry of the 1,4-addition can be controlled to give either cis or trans 1,4-addition across the double bonds. The oxaspirocyclization was applied to the total synthesis of theaspirone.
