Migratory components

Bilodeau [4] prepared barriers consisting of radiation cured A -vinyl-2-pyrro-lidone and A -vinylcaprolactam that were impervious to migratory components in autmotive tires. 

Energy curable adhesives for use in flexible packaging based on ultraviolet or electron beam irradiation are in their infancy. The potential use of these types of adhesive is promising due to the fast cure rate (essentially full cure on irradiation and hence low risk of migratory components) and the potentially... 

The antennal olfactory receptor system in several phytophagous insects is very sensitive in the detection of the green odour components. In the Colorado beetle Leptinotarsa decemlineata, the threshold of response for trans-2-hexen-1-ol is circa 10b molecules per ml of air (17). In comparison, at 760 mm Hg and 20 C, 1 ml of air contains about 1019 molecules. The insects tested i.e., the migratory locust Locusta migratoria, the carrot fly Psila rosae (18), the cereal aphid Sitobion avenae (19), the Colorado beetle L. decemlineata (17), Leptinotarsa... 

The mechanism of this three-component coupling reaction is probably analogous to the aforementioned insertion of acyl chlorides (above). One can imagine assembling an intermediate acylpalladium species either by oxidative addition to an acyl chloride or, in this case, by oxidative addition to the aromatic iodide followed by migratory insertion into carbon monoxide. Once formed, the acylpalladium intermediate can insert into the SCB to furnish a 7-(chlorosilyl)propyl ketone, which cyclizes in the presence of the amine to afford cyclic enol ethers. 

Nickel(II) complexes obtained from nickel(0) or nickel(II) compounds and the (Me3Si)2NP(=NSiMe3)2 phosphorane component, which promote the isomerisation 2, co-polymerisation of a-olefins, are referred to as nickel migratory catalysts. It must be emphasised that this is a peculiarity of the (Me3Si)2NP(=NSiMe3)2 phosphorane other phosphoranes of this type in which only one silicon atom is substituted by a carbon atom give an inactive catalyst [183],... 

Scheme 4) [57], In this case, when /V-vinyl imides were used as the olefin component, the predominant Heck product resulted from palladium migration. Other olefins, including vinyl esters, did not afford palladium migration products. While the reason for the success with Wvinyl imides is unclear, it has been pointed that these olefins may serve as ligands to stabilize the palladium and slow down the migratory insertion,... 

A reaction with a similar outcome involves migration of one ligand to attack another adjacent ligand (a 1,1-migratory insertion), promoted by the availability of another ligand to occupy the site vacated by the first movement. In example (6.49) below, an initial R—M—C=0 component of the molecule is converted to an —M—C(R)=0 component, leaving a vacant coordination site, filled by an added phosphine ligand in this case. 

Outer or transit packaging can occasionally contribute to changes in the primary pack or the product. External wrapping materials may contain various migratory constituents, e.g. when a shrink or stretch film is in intimate contact with a primary pack or plastic components of a device. Odorous board, adhesives, printing inks on external packaging have also been known to cause flavour and/or odour changes. 

Dehydroretinal, 3,4-Didehydroretinat 3,7-di-methyl-9-(2 6 6-triniethyi-l,3-cyclohexadien 1 -yl)-2,4,6,8-nonatetraena) retinal 2 retinene 2 vitamin A2 aldehyde. c hm° mo1 wt 282.42. C 85.06%. H 9.28%, O 5,66%. Carotenoid component of the visual pigments of fresh -water and migratory fish, lampreys and certain amphibians- Of the 16 possible stereoisomers 7 have been synthesized. The 11 -ei-s.isomer is the chromophore of porphyropsin and cyanopsin, q.q. y. Isoln from retinas of fresh-water fish G. Wald, Nature 139, 1017 (1937). Recognition as vitamin A2 aldehyde R. A. Morton, ibid. 153, 69(1944). Prepn by the... 

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