Compounds, colored Ethylene

The cadmium chalcogenide semiconductors (qv) have found numerous appHcations ranging from rectifiers to photoconductive detectors in smoke alarms. Many Cd compounds, eg, sulfide, tungstate, selenide, teUuride, and oxide, are used as phosphors in luminescent screens and scintiUation counters. Glass colored with cadmium sulfoselenides is used as a color filter in spectroscopy and has recently attracted attention as a third-order, nonlinear optical switching material (see Nonlinear optical materials). DiaLkylcadmium compounds are polymerization catalysts for production of poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVA), and poly(methyl methacrylate) (PMMA). Mixed with TiCl, they catalyze the polymerization of ethylene and propylene. 

An alkene, sometimes caJled an olefin, is a hydrocarbon that contains a carbon-carbon double bond. Alkenes occur abundantly in nature. Ethylene, for instance, is a plant hormone that induces ripening in fruit, and o-pinene is the major component of turpentine. Life itself would be impossible without such alkenes as /3-carotene, a compound that contains 11 double bonds. An orange pigment responsible for the color of carrots, /3-carotene is a valuable dietary source of vitamin A and is thought to offer some protection against certain types of cancer. 

Tetracyanoethylene (500 mg TCNE dissolved in 100 ml of acetonitrile or ethylene acetate) reacts with aromatic compounds, forming colored zones on a slightly yellow background. In some cases, heating to 100°C is necessary to complete the reaction. 

Smoke flavoring, 12 48 Smoke generation tests, 19 588 Smoke point, of fats and oils, 10 822 Smoke retardants, molybdenum compounds in, 17 39 Smoke suppression, by ethylene-acrylic elastomers, 10 700 Smoking, age-related macular degeneration and, 17 659 Smoky quartz color, 7 337... 

We have recently reported that compound 7a shows a smectic-smectic phase transition associated with the change of the photoluminescent color (Fig. 7) [33]. Compound 7a has a 2,6-diethynylanthracene group as a photoluminescent core. This molecule has fork-like mesogens which consist of tetra(ethylene oxide) and p-(4-/ra .v-pentylcyclohexyl)phenyl moieties. A similar molecular design was previously applied to induce smectic liquid crystallinity for rotaxanes and catenanes [39—41 ]. 

At room temperature, methylene trimethylarsorane (73) is a colorless crystalline compound, mp 33°C, which sublimes in a vacuum at 20°C/0.1 mm Hg. It is rapidly decomposed above 33°C trimethylarsine and polymethylene are the main products formed. Blue and brown colors develop and some gas is evolved, predominantly ethylene. With trimethylphos-phine, a methylene transfer reaction takes place yielding trimethylarsine and methylene trimethylphosphorane ... 

The Ziegler-Natta catalysts are mixtures of solid and liquid compounds containing a transition metal such as titanium or vanadium (16). The first catalyst used by Ziegler and coworkers for the polymerization of ethylene was a mixture of TiCLt and AlEt3. Each of these is soluble in hydrocarbon solvents, but when they are combined an olive-colored, highly sensitive... 

Although having excellent color in most systems, the antioxidant activity of these compounds in certain systems such as polypropylene and ethylene-propylene rubber has been only fair. Possibly intramolecular hydrogen bonding between the phenolic hydroxyl and the benzylic sulfur... 

Oxidation of di-(2-quinolyl)methanes with chromic acid in 5% sulfuric acid yields, besides small quantities of 13, the tetraquinolyl-ethanes (17) as main product in 2.5% sulfuric acid the tetraquinolyl-ethylenes (16) are formed, and in concentrated sulfuric acid under the same conditions (heating on a water bath) no oxidation occurs at all.38 In contrast to the colorless compounds (16), compounds 17 are able to form the tautomeric colored species (17a). 

The final paper (44) reported the finding that nitro compounds such as trinitromesitylene and tetranitromethane give colors with aromatic hydrocarbons and amines. Saturated aliphatic compounds give no color with tetranitromethane, but unsaturated aliphatic compounds act like hydrocarbons as long as the ethylene link does not adjoin a carboxyl group. Werner concluded that the colored compounds result from the interaction of subsidiary valencies associated with the nitro group on one hand, and... 

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