- Syntheses and palladium, platinum, and borane adducts of symmetrical trialkylphosphines with three terminal vinyl groups, P((CH2) mCH=CH2)3
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Reactions of Br(CH2)mCH=CH2 with Mg powder and then PCl3 (0.33 equiv.) afford P((CH2)m-CH=CH 2)3 (1; m = a, 4; b, 5; c, 6; d, 7; e, 8; f, 9; 52-87 %). Reactions of 1a-c, e with PdX2(COD) (X = Cl, Br) give trans-PdX 2(P((CH2)mCH=CH2)3) 2 (35-92 %). Reactions of 1b-e with PtCl2 in benzene give mainly trans-PtCl2(P((CH2)mCH=CH 2)3)2 (trans-5b-e; 52-75 %), whereas those with K2PtCl4 in water give mainly cis-5b-e (33-70 %). The reaction of equimolar quantities of 1c and H3B.S(CH3) 2 gives the 1 : 1 adduct H3B·P((CH 2)6CH=CH2)3 (85 %). In none of these transformations are by-products derived from the C=C linkages observed.
- Nawara-Hultzsch, Agnieszka J.,Skopek, Katrin,Shima, Takanori,Barbasiewicz, Micha,Hess, Gisela D.,Skaper, Dirk,Gladysz, John A.
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experimental part
p. 414 - 424
(2010/10/01)
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- Silver-catalyzed alkyl-alkyl homo-coupling of Grignard reagents
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Oxidative homo-coupling of alkyl Grignard reagents possessing β-hydrogens proceeded with high selectivity in the presence of silver tosylate (AgOTs) as a catalyst (1 mol %) and 1,2-dibromoethane as a reoxidant. Copyright
- Nagano, Takashi,Hayashi, Tamio
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p. 1152 - 1153
(2007/10/03)
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- Semivolatile and volatile compounds in combustion of polyethylene
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The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
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p. 615 - 627
(2007/10/03)
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- SYMMETRICAL AND UNSYMMETRICAL COUPLING OF ALKYL HALIDES MEDIATED BY GRIGNARD REACTION
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A simple method for extending the carbon chain via the coupling of alkyl or aryl halides has been developed.The versatility of this reaction has been demonstrated by symmetrical and unsymmetrical coupling of alkyl, alkenyl or alkynyl halides.
- Herendeen, Barbara L.,Bhatia, Suresh K.,Singh, Alok
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p. 2899 - 2908
(2007/10/02)
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- THE INVENTION OF RADICAL REACTIONS. PART XV. SOME MECHANISTIC ASPECTS OF THE DECARBOXYLATIVE REARRANGEMENT OF THIOHYDROXAMIC ESTERS
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Esters (mixed anhydrides) derived from aliphatic or alicyclic carboxylic acids (RCO2H) and thiohydroxamic acids 2 or 3 undergo a thermally or photochemically induced radical chain reaction to give sulphides 4 with loss of carbon dioxide.On irradiation at low temperature however, the chain reaction is essentially suppressed.Under these conditions moderate to good yields of dimers R-R are obtained from primary acids.The mechanistic and synthetic implications of these observations are discussed.
- Barton, Derek H. R.,Bridon, Dominique,Fernandez-Picot, Isabel,Zard, Samir Z.
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p. 2733 - 2740
(2007/10/02)
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