Unsaturation hydrocarbons with

Alkenes — Also known as olefins, and denoted as C H2 the compounds are unsaturated hydrocarbons with a single carbon-to-carbon double bond per molecule. The alkenes are very similar to the alkanes in boiling point, specific gravity, and other physical characteristics. Like alkanes, alkenes are at most only weakly polar. Alkenes are insoluble in water but quite soluble in nonpolar solvents like benzene. Because alkenes are mostly insoluble liquids that are lighter than water and flammable as well, water is not used to suppress fires involving these materials. Because of the double bond, alkenes are more reactive than alkanes. 

Another analogous series of unsaturated hydrocarbons that contain just one multiple bond, but, instead of being a double bond, it is a triple bond is the alkynes. The names of all the compounds end in -yne. The only compound m this series that is at all common happens to be an extremely hazardous material. It is a highly unstable (to heat, shock, and pressure), highly flammable gas that is the first compound in the series. This two-carbon unsaturated hydrocarbon with a triple bond between its two carbon atoms is called ethyne, and indeed this is its proper name. It is, however, known by its common name, acetylene. 

Schaarschmidt and Hoffrneier (Ref 2) found that on treating an unsaturated hydrocarbon with NLQ4 a mixt of products of the I, II III and IV types was obtained. Only the dinitro compds of type III were stable. Others underwent decomposition in the following way ... 

This review has been concerned largely with interactions and reactions of unsaturated hydrocarbons with zinc oxide. The picture of the active site as a metal oxide pair capable of heterolytic fission of an acidic C—H bond provides a consistent framework for discussion of these results. We believe this view may be generally applicable. In its application, however, we must keep in mind that zinc oxide may be much more effective for heterolytic cleavage (i.e., more basic) than oxides such as, say, alumina.4... 

Microcrystalline wax is found worldwide as a constituent of crude oil. It is removed by solvent extraction and distillation. The colour varies, depending on grade, from white to brown black. It has many uses, including waterproofing paper and textiles, and as a sealant. This wax consists of a mixture of long chain (C41 C57) unsaturated hydrocarbons with an average molecular weight of 500 800. 

A series of investigations was performed on the structure of the complexes formed by unsaturated hydrocarbons with lithium dissolved in a solid argon matrix. The structures proposed for these complexes are based on assignment of the perturbations observed in the IR spectra of the free hydrocarbons and their isotopically enriched species. 

The reaction of unsaturated hydrocarbons with bromine is synthetically important. Unsaturated fatty acids have been electrobrominated in an acetic acid/acetonitrile medium and at platinum electrodes [128]. The mechanism and rate constant for the process with oleic, erucic, and linoleic acid were elucidated. The a-bromination of a,f-unsaturated ketones has been reported [129] on the basis of the electrolysis of a substrate/CF3COOH/CuBr/Et4NOTs/ MeCN reaction system. CuBr is present as a catalyst. 

Benter, Th., M. Liesner, R. N. Schindler, H. Skov, J. Hjorth, and G. Restelli, REMPI-MS and FTIR Study of N02 and Oxirane Formation in the Reactions of Unsaturated Hydrocarbons with NO, Radicals, . /. Phys. Chem., 98, 10492-10496 (1994). 

The first metal-olefin complex was reported in 1827 by Zeise, but, until a few years ago, only palladium(II), platinum(Il), copper(I), silver(I), and mercury(II) were known to form such complexes (67, 188) and the nature of the bonding was not satisfactorily explained until 1951. However, recent work has shown that complexes of unsaturated hydrocarbons with metals of the vanadium, chromium, manganese, iron, and cobalt subgroups can be prepared when the metals are stabilized in a low-valent state by ligands such as carbon monoxide and the cyclopentadienyl anion. The wide variety of hydrocarbons which form complexes includes olefins, conjugated and nonconjugated polyolefins, cyclic polyolefins, and acetylenes. 

Alkynes An analogous series of unsaturated hydrocarbons with the general formula C,HM the alkynes all contain just one triple bond between carbon atoms. 

The second approach is that developed to interpret the products of the reactions of octalins with deuterium [144] and is equally applicable to the reactions of mono- or di-unsaturated hydrocarbons with deuterium. Smith and Burwell [144] pointed out that, whereas the experimental deuterohydrocarbon distributions are obtained in terms of the number of deuterium atoms in the product hydrocarbon, the quantities of fundamental importance to the discussion of the mechanisms of catalytic reactions are the fractions of the hydrocarbon sample which have equilibrated with the surface deuterium—hydrogen pool. Thus, for example, in the reaction of buta-1 3-diene with deuterium, the product butenes consist of a series of species, butene-(/i, d)2, -(h, d)3,..., -(h, d)n in which 2,3. .., n positions... 

Testing for Unsaturated Hydrocarbons with Bromine movie... 

Alkenes A family of unsaturated hydrocarbons with the general formula CnH2n. The term unsaturated, in this context, is used to describe molecules which contain one or more carbon-carbon double bonds. Unsaturated compounds undergo addition reactions across the carbon-carbon double bonds and so produce saturated compounds. The addition of hydrogen across the carbon-carbon double bonds is used to reduce the amount of unsaturation during the production of margarines. 

Several recent publications are focused on allylic and benzylic tosylamida-tions of a range of unsaturated hydrocarbons with Phi = NTs [192-196]. Salen-Mn(III) complexes, Ru(II) and Mn(III)-porphyrins, and Ru(II)- and Ru(III)-amine complexes were employed as catalysts for this purpose, and issues pertaining to catalyst efficiency and enantioselectivity of tosylamidation were addressed. Examples are shown in Scheme 71 [192,193]. 

This paper presents a new method for preparing 1,2-bis-(dichlorophosphino)alkanes based on the reaction of unsaturated hydrocarbons with PCl and elemental phosphorus at 180-250°C under autogenous pressureI. The basic reaction with ethylene is... 

Alkenes (unsaturated hydrocarbons with double bonds) are the oldest and most studied carbon ligands, with interest in their study dating from around 1827 [3,185-189]. An important aspect is the structure of 71-alkene and similar n-alkyne complexes. Their structural data is summarized in reviews [186-189] and presented in... 

Complex compounds with halide bridges are prepared by immediate interaction of unsaturated hydrocarbons with metal salts (Sec. 2.2.4.1). Their examples are classic 7i-complexes of the type 123 which are characteristic for fi 8-metals [75]. Such complexes are also formed by the method of ligand exchange. The bridges of this type are widespread in products of cyclometallation reactions with the use of metal halides (Sec. 2.2.5.1) 371-374, 381, 382 [41,46,48]. An example of such a synthesis is the reaction of arylhydrazones of 2-oxopropionic aldehyde and benzoylformalde-hyde, as well as butadiene-2,3-dione 635, with palladium dichloride, leading (3.71) to dipalladium complexes 636 [88] ... 

Styrene and 1-hexene have been selectively hydrogenated as well as substituted acetylenes, alkyne diols, stilbene and other unsaturated hydrocarbons with these palladium montmorillonites. A size selectivity was invoked to explain the enhanced hydrogenation activity of certain clay catalysts presumably due to the differences in interlamellar spacings of the clay which will depend on degree of hydration, concentration of Pd(II) complex, dielectric constant of the solvent used to disperse the reactants and other factors. 

Chamazulene A bicyclic unsaturated hydrocarbon with the molecular formula C14H16. It does not belong to the sequiterpenes but is historically included with them. It is an azulene which are compounds derived from sequiterpenes. Chamazulene is formed by the breakdown of matricine during the steam distillation process. 

Diterpenes Unsaturated hydrocarbons with the empirical formula C20H32, considered to be dimers of monoterpenes C10H16. 

Systematic examination of the catalytic properties of dimeric complexes was initiated shortly after the identification of dinuclear iron sites in metalloenzymes. The first report of a reactive dimeric system came from Tabushi et al. in 1980, who examined the catalytic chemistry of [Fe3+(salen)]20, 1 (salen is N,N -(salicylaldehydo)-l,2-ethylenediamine) (12). They reported interesting stereoselectivity in the oxidation of unsaturated hydrocarbons with molecular oxygen in the presence of mercaptoethanol or ascorbic acid and pyridine as a solvent ([l]<<[alkane]<<[2-mercaptoethanol]). With adamantane as substrate, they observed the formation of a mixture of (1- and 2-) adamantols and adamantanone (Table I) (12). Both the relative reactivity between tertiary and secondary carbons (maximum value is 1.05) and final yield ( 12 turnovers per 12 hr) were dependent on the quantity of added 2-mercaptoethanol. Because autoxidation of adamantane gave a ratio of 3°/2° carbon oxidation of 0.18-0.42, the authors proposed two coexisting processes autooxidation and alkane activation. 

Acetylene only becomes stable in relation to the simplest paraffins at temperatures substantially above 1000. The situation is more favorable for unsaturated hydrocarbons with lower energy content, such as ethylene, which is stable in relation to ethane above 750"C, and benzene, which is favored in relation to normal hexane above 350 to 400 C. 

The carbocations considered here have three, five, seven, nine or eleven carbon atoms. In their comprehensive review Leone et al. (1973) point out that carbocations with the empirical formula (CH) , where n is odd, are related to the unsaturated hydrocarbons with the formula (CH) , where m = 1. By the mathematical treatment developed by Balaban (1966), all valence isomers of (CH) hydrocarbons can be derived. Thus through this... 

A major effort to study the chemistry of the zero oxidation state lanthanides on a preparative scale involved their reactivity with neutral unsaturated hydrocarbons 14, 60). This class of reagents was of interest because reactions of unsaturated hydrocarbons with metals constitute such an important component of organometallic chemistry and because species such as alkenes and alkynes were not common as ligands or reactants in organolanthanide chemistry at that time. 

Mountfort D. O. and Kaspar H. F. (1986) Palladium-mediated hydrogenation of unsaturated hydrocarbons with hydrogen gas released during anaerovic cellulose degradation. Appl. Environ. Microbiol. 52, 744-750. 

For ethane, adsorption values of 4.04 wt% for DD3R were found while Na-A adsorbs 7.4 wt% at similar conditions (700 Torr, 25°C), so DD3R adsorbs 54.6% of the amount of ethane adsorbed on zeolite A. The accessible volume of DD3R is 0.48% compared with zeolite A, so based on the void volume, both materials show comparable adsorption of a non-polar molecule. The adsorption of ethylene amounts to 43.5 %, compared to zeolite A (3.65 wt% and 8.4 wt%, respectively). The slightly higher preference of zeolite A for an aUcene can be ejqrlained in terms of stronger interactions of an unsaturated hydrocarbon with the ionic nature of the zeolite A surfece. Calcium-exchanged type A zeolites were found to exhibit the same behaviour firr propane and propylene [38]. 

The most important additional products observed at very high temperatures were ketene, methyl vinyl ketone and ethylene, as well as some saturated and unsaturated hydrocarbons with more than two carbon atoms . The formation of carbon and tar, as well as the occurrence of wall catalytic effects were also reported . It is evident that new elementary reactions occur and the mechanism of the photolysis is rather complex above 300 °C. Brinton suggested a new ethane-producing reaction. Various possibilities were considered for the formation of ethylene, however, none of these can be regarded as adequately proved. 

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