Hydrocarbon alkenes

We will return to the orbital hybridization model to discuss bonding m other aliphatic hydrocarbons—alkenes and alkynes—later m the chapter At this point how ever we 11 turn our attention to alkanes to examine them as a class m more detail... 

Aromatic ethers and furans undergo alkoxylation by addition upon electrolysis in an alcohol containing a suitable electrolyte.Other compounds such as aromatic hydrocarbons, alkenes, A -alkyl amides, and ethers lead to alkoxylated products by substitution. Two mechanisms for these electrochemical alkoxylations are currently discussed. The first one consists of direct oxidation of the substrate to give the radical cation which reacts with the alcohol, followed by reoxidation of the intermediate radical and either alcoholysis or elimination of a proton to the final product. In the second mechanism the primary step is the oxidation of the alcoholate to give an alkoxyl radical which then reacts with the substrate, the consequent steps then being the same as above. The formation of quinone acetals in particular seems to proceed via the second mechanism. ... 

The condition defined by equation (8) is met by adjustment of (Qg(3)) nd (T(3)). The pressures at the second stripping flow inlet and that of the outlet for solute (C) must be made equal, or close to equal, to prevent cross-flow. Scott and Maggs [7] designed a three stage moving bed system, similar to that described above, to extract pure benzene from coal gas. Coal gas contains a range of saturated aliphatic hydrocarbons, alkenes, naphthenes and aromatics. In the above theory the saturated aliphatic hydrocarbons, alkenes and naphthenes are represented by solute (A). 

Saturated hydrocarbons have only single bonds unsaturated Ihydrocarbons have one or more multiple bonds. Alkanes are saturated hydrocarbons. Alkenes and alkynes are unsaturated hydrocarbons the former have carbon-carbon double bonds and the latter have triple bonds. 

Nonaromatic hydrocarbons that do not contain such a ring system. Included here are alkanes, which are fully saturated hydrocarbons alkenes, which contain one or more double bonds and alkynes, which contain one or more triple bonds. 

Wilhoit, R.C., Marsh, K.N., Hong, X., Gadalla, N., Frenkel, M. Densities of Aliphatic Hydrocarbons Alkenes, Alkadienes, Alkynes and Miscellaneous Compounds. 

The Fischer-Tropsch synthesis, which may be broadly defined as the reductive polymerization of carbon monoxide, can be schematically represented as shown in Eq. (1). The CHO products in Eq. (1) are any organic molecules containing carbon, hydrogen, and oxygen which are stable under the reaction conditions employed in the synthesis. With most heterogeneous catalysts the primary products of the reaction are straight-chain alkanes, while the secondary products include branched-chain hydrocarbons, alkenes, alcohols, aldehydes, and carboxylic acids. The distribution of the various products depends on both the type of catalyst and the reaction conditions employed (4). 

Tetraborane(lO) reacts, as does diborane, readily with unsaturated hydrocarbons. Alkenes give access to B2,B4-alkylene bridged B4H8(RCH-CHR) organo-boranes [37] while alkynes, allenes and l-ene-3-ynes lead to a variety of carba-boranes [38-40]. 

The composition consists of approximately 64% aliphatic hydrocarbons (straight-chain alkanes and cycloalkanes), 1 to 2% unsaturated hydrocarbons (alkenes), and 35% aromatic hydrocarbons (including alkylbenzenes and two- and three-ring aromatics). No 2 fuel oil contains less than 5% polycyclic aromatic hydrocarbons. 

It is a useful oxidant for hydrocarbons, alkenes, alcohols and aldehydes. Permanganate reacts with carbon-carbon double bonds to form a cyclic manganate(V) diester. The nature of the products is determined by subsequent rapid processes. 

Alkenes and alkynes are unsaturated hydrocarbons. Alkenes contain at least one carbon-carbon double bond and alkynes have at least one carbon-carbon triple bond. The names of alkenes and alkynes use the alkane prefixes, but add ene and yne endings, respectively (Table 15.3). 

Alkane an acyclic saturated hydrocarbon Alkene an acyclic hydrocarbon that contains at least one carbon-carbon double bond... 

Butenes or butylenes are hydrocarbon alkenes that exist as four different isomers. Each isomer is a flammable gas at normal room temperature and one atmosphere pressure, but their boiling points indicate that butenes can be condensed at low ambient temperatures and/or increase pressure similar to propane and butane. The 2 designation in the names indicates the position of the double bond. The cis and trans labels indicate geometric isomerism. Geometric isomers are molecules that have similar atoms and bonds but different spatial arrangement of atoms. The structures indicate that three of the butenes are normal butenes, n-butenes, but that methylpropene is branched. Methylpropene is also called isobutene or isobutylene. Isobutenes are more reactive than n-butenes, and reaction mechanisms involving isobutenes differ from those of normal butenes. 

In acid-catalyzed reactions of unsaturated hydrocarbons (alkenes, alkynes, arenes) positive hydrocarbon ions—carbocations—are formed, which are then responsible for the electrophilic transformations 93b... 

Unsaturated hydrocarbons (alkenes, dienes) react with carbon monoxide and a proton source (H20, alcohols, amines, acids) under strong acidic conditions to form carboxylic acids or carboxylic acid derivatives. Since a carbocationic mechanism is operative, not only alkenes but also other compounds that can serve as the carbocation source (alcohols, saturated hydrocarbons) can be carboxylated. Metal catalysts can also effect the carboxylation of alkenes, dienes, alkynes, and alcohols. 

While the above details provide a general procedure for handling mixtures of acidic, basic and neutral components, other selective extraction reagents may be utilised in certain special instances. For example, cold concentrated sulphuric acid will remove unsaturated hydrocarbons (alkenes and alkynes) present in... 

Saturated hydrocarbons > alkenes, alkynes, aromatic hydrocarbons > esters, aldehydes and ketones > amines, alcohols, thiols > phenols, carboxylic acids. 

There are two types of donors, ru-donors and n-donors. In the former, the electron available for donation is located in the n-MO of the molecule, e.g. aromatic hydrocarbons, alkenes, alkynes. They are said to form -complexes. In the second type of donors, a nonbonding (Mectron is transferred. The examples of n-donors are alcohols, amines, ethers, etc. 

It was initially presumed that one would observe a polarity-driven kinetic advantage in 5-hexenyl radical cyclizations if one constructed such radicals with either a hydrocarbon radical site adding to a fluorinated alkene segment or, vice-versa, with a fluorinated radical site adding to a hydrocarbon alkene segment. As it turns out, only the latter combination led to a significant cycliza-tion rate enhancement. 

Cyclizations Involving Fluorinated Radical Adding to Hydrocarbon Alkene... 

Table 17. Absolute rate constants for 5-hexenyl radical cyclizations involving fluorinated radical addition to hydrocarbon alkens, at 30 °C in C6D6 [140,162] ...

Silica gel 300 H2, air, CO, 0,-0, normal hydrocarbons, alkenes, alkynes Used often as a second column (with a molecular sieve) very hydrophilic requires activation can be unpredictable largely replaced by porous polymers... 

Hydrocarbons, alkenes and alkynes react with SiO to form white solids, which are stable up to 350 °C. Their structure is unknown the IR-spectrum indicates Si—O, C-H and Si—H bonds. The SiO probably reacts with the C-C double bond and also with the C-H bond ... 

Having studied the reactions involving alkynes in some detail we turned our attention to other unsaturated molecules, and in particular simple hydrocarbons. Alkenes appear unreactive, though allenes, as shown in the following section, do yield novel products. 

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