Olefinic unsaturation

Oxidative Garbonylation. Carbon monoxide is rapidly oxidized to carbon dioxide however, under proper conditions, carbon monoxide and oxygen react with organic molecules to form carboxyUc acids or esters. With olefins, unsaturated carboxyUc acids are produced, whereas alcohols yield esters of carbonic or oxalic acid. The formation of acryUc and methacrylic acid is carried out in the Hquid phase at 10 MPa (100 atm) and 110°C using palladium chloride or rhenium chloride catalysts (eq. 19) (64,65). 

Selective hydrogenation of the carboxyl or ester group in preference to the olefinic unsaturation also produces unsaturated alcohols. 

Liquefied Petroleum Gas The term liquefied petroleum gas (LPG) is applied to certain specific hydrocarbons which can be liquefied under moderate pressure at normal temperatures but are gaseous under normal atmospheric conditions. The chief constituents of LPG are propane, propylene, butane, butylene, and isobutane. LPG produced in the separation of heavier hydrocarbons from natural gas is mainly of the paraffinic (saturated) series. LPG derived from oil-refinery gas may contain varying low amounts of olefinic (unsaturated) hydrocamons. 

Since it is well known that chloroalkenes are often much less stable than the corresponding alkanes, olefinic unsaturation may be an important source of thermal instability in PVC. Chain-end unsaturation could arise by disproportionation during bimolecular reaction of polymer radicals Eq. (2). 

Hydrogenation of olefinic unsaturation using ruthenium (Ru) catalyst is well known. It has been widely used for NBR hydrogenation. Various complexes of Ru has been developed as a practical alternative of Rh complexes since the cost of Ru is one-thirtieth of Rh. However, they are slightly inferior in activity and selectivity when compared with Rh catalyst. 

This method provides a convenient synthesis of alkenes with the double bond in a relatively unstable position. Thus reduction of the p-toluenesulfonylhydrazones of a,(3-unsaturated aryl ketones and conjugated dienones gives rise to nonconjugated olefins. Unsaturated ketones with endocyclic double bonds produce olefins with double bonds in the exocyclic position. The reduction of p-toluenesulfonylhydrazones of conjugated alkynones furnishes a simple synthesis of 1,3-disubstituted allenes. ... 

One such reported example is the synthesis of polypropylene-6-polymethyl-methacrylate (PP-6-PMMA) copolymers utilizing metallocene catalysis and the borane chemistry. In the initial step, PP with chain-end olefinic unsaturations was prepared using metallocene catalysts such as Et(Ind)2ZrCl2/MAO. The unsaturation sites were then hydroborated by 9-borabicyclo[3.3.1]nonane (9-BBN) to produce borane-terminated PP (43) (Fig. 30), which was selectively oxidized and interconverted to a... 

Figure 30 The hydroboration strategy of chain end olefinic unsaturation in polypropylene with 9-BBN for further conversion into block copolymers via polymer radicals. (Adapted from refs. 66 and 67.)...

Some of the vinyl monomers polymerized by transition metal benzyl compounds are listed in Table IX. In this table R represents the rate of polymerization in moles per liter per second M sec-1), [M]0 the initial monomer concentration in moles per liter (M) and [C]0 the initial concentration of catalyst in the same units. The ratio i2/[M]0[C]0 gives a measure of the reactivity of the system which is approximately independent of the concentration of catalyst and monomer. It will be observed that the substitution in the benzyl group is able to affect the polymerization rate significantly, but the groups that increase the polymerization rate toward ethylene have the opposite effect where styrene is concerned. It would also appear that titanium complexes are more active than zirconium. The results with styrene and p-bromostyrene suggests that substituents in the monomer, which increase the electronegative character of the double bond, reduces the polymerization rate. The order of reactivity of various olefinically unsaturated compounds is approximately as follows ... 

The fatty acids measured by these techniques have all been small monomeric molecules. Lamar and Goerlitz [ 125] studied the acidic materials in highly coloured water and found that most of the nonvolatile material was composed of polymeric hydroxy carboxylic acids, with some aromatic and olefinic unsaturation. Their methods included gas, paper, and column chromatography with infrared spectrophotometry as the major technique used for the actual characterisation of the compounds. 

Olefinic, unsaturated hydrocarbons have CH groups adjacent to C=C double bonds. The C=C vibrations do not show up directly except as weaker contributions in the combination region, but the nucleophilic effect of the C=C bond tends to shift nearby CH groups to significantly higher wavenumber, and this is indeed seen in hydrocarbon spectra (Figure 5.32). 

OLEFINS. Unsaturated aliphatic hydrocarbons with great chemical activity. 

The compositions consist of a heat-plastified mixture of an ethylene homopolymer or copolymer, about 3 to 30 pbw of an elastomer, a stability control agent, which is a partial ester of a long chain fatty acid with a polyol, higher allyl amine, fatty acid amide or olefinically unsaturated carboxylic acid copolymer, and a hydrocarbon blowing agent having from 1 to 6 carbon atoms and a boiling point between -175 and 50C. 

Bohnen et report a hydroformylation method to convert olefins or olefinically unsaturated compounds in the presence of at least one rhodium compound and sulfonated arylphosphines in ILs based on a quaternary ammonium ion or the equivalent of a multiply charged ammonium ion and organic sulfonates or sulfates. 

High polymers of isobutylene prepared in the absence of a diolefin are also produced commercially and are available in various molecular weight ranges under the name Vistanex (42). These materials are not vulcanizable by ordinary means as they are substantially free of residual olefinic unsaturation, and they have been used principally for compounding with other polymers or for special applications such as gaskets, tank liners, or calking compounds. 

Hydrogenation and hydrocracking activity of iron catalysts has been extensively investigated using coal and model compounds (93 -95). Iron catalysts can hydrogenerate olefinic unsaturated bonds, while they are known to be less active for the hydrogenation of aromatic rings compared with molybdenum-based catalysts. 

The formation of branched polymer molecules results also from chain transfer reactions with the monomer in this case the chain transfer produces in the polymer molecule an olefinic unsaturation, the consequences of which will be considered later. 

An investigation with the electron donor 4-methoxybenzo[b]thiophene (35) and electron acceptor p-chloroacetophenone (36) and with the bichro-mophores 37 and 38, where the above donor and acceptor moieties are connected by an olefinic (unsaturated as well as saturated) spacer, was performed (02JPP(A)(152)41). The absorption spectra of the donor 35 in the presence of the electron acceptor 36 were measured in n-heptane and highly polar acetonitrile solutions. In both nonpolar and highly polar media, it was found that the spectra of the mixture of 35 and 36 are just the superposition of the absorption bands of the individual components. This observation excludes the possibility of formation of any ground state charge transfer (CT) complex. 

Callahan J. L., Milberg, E. C., Process for preparing olefinically, unsaturated nitriles, USP 3230246, 1966... 

Thermal decomposition of the sodium salts of tosylhydrazones 45a-e gave the triene-conjugated diazo 46a-e, which have a,(3 aromatic and 7, e,C olefinic unsaturation. Such diazo compounds react at 25 °C via an intramolecular [3+2] cycloaddition with unprecedented regioselectivity to give the bridged benzodiazocine 6a-e. 

Graft copolymers are obtained by subsequent radical emulsion polymerisation of olefinic unsaturated monomers in the presence of functionalized siloxane particles. Scheme 3 illustrates that the graft... 

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