Olefin hydrogenation acrylic acids

The Diels-Alder reaction of a diene with a substituted olefinic dienophile, e.g. 2, 4, 8, or 12, can go through two geometrically different transition states. With a diene that bears a substituent as a stereochemical marker (any substituent other than hydrogen deuterium will suffice ) at C-1 (e.g. 11a) or substituents at C-1 and C-4 (e.g. 5, 6, 7), the two different transition states lead to diastereomeric products, which differ in the relative configuration at the stereogenic centers connected by the newly formed cr-bonds. The respective transition state as well as the resulting product is termed with the prefix endo or exo. For example, when cyclopentadiene 5 is treated with acrylic acid 15, the cw fo-product 16 and the exo-product 17 can be formed. Formation of the cw fo-product 16 is kinetically favored by secondary orbital interactions (endo rule or Alder rule) Under kinetically controlled conditions it is the major product, and the thermodynamically more stable cxo-product 17 is formed in minor amounts only. 

Hirai et al.129 studied the hydrogenation of olefins catalyzed by poly(acrylic acid)-Rh(II) complexes in homogeneous solutions. The catalytic activity of the polymer-Rh complex was about 103 times that of the acetato-Rh complex. When olefins having another functional group, such as diallylether, allylaldehyde, and cyclohexene-1 -one, were used as the substrates, the olefinic bond was preferentially hydrogenized by the polymer-Rh complex. The polymer ligand was presumed to exercise a steric effect. 

Palladium complexes of chitin and chitosan have been shown to be active, selective, and stable catalysts for the hydrogenation of olefins, acrylic acid, nitrobenzene etc. at room temperature. Their catalytic activities can be controlled by changing the pH of the solution 90). 

The Monsanto group also extended their studies to other substrates (particularly a,/3-unsaturated acids) and other phosphines. In these later experiments, they generated the catalyst in situ, as the Horner group had done. A methanol solution containing an a-substituted acrylic acid and a trace amount of triethyla-mine was then added, and hydrogenations were carried out at 30 atm H2 and 60°C. For various combinations of olefin and chiral ligand, optica] purities ranged from 3 to 21% (Fig. 6). 

In allylic oxidation, an olefin (usually propylene) is activated by the abstraction of a hydrogen a to the double bond to produce an allylic intermediate in the rate-determining step (Scheme 1). This intermediate can be intercepted by catalyst lattice oxygen to form acrolein or acrylic acid, lattice oxygen in the presence of ammonia to form acrylonitrile, HX to form an allyl-substituted olefin, or it can dimerize to form 1,5-hexadiene. If an olefin containing a jS-hydrogen is used, loss of H from the allylic intermediate occurs faster than O insertion, to form a diene with the same number of carbons. For example, butadiene is fonned from butene. 

The first example of activation of molecular Hj by a Ru(II) species was described in 1961. The study employed a solution of Ru(II) choride in aqueous HCl at 65 to 95°C and H2 P of about 1 atm to catalytically hydrogenate maleic, fumaric, and acrylic acid. The Ru(II) species that are prepared in situ by reduction of solutions of Ru(III) with Ti(III) is thought to be RuCl . The latter blue solutions turn yellow in the presence of the olefin substrates, and they absorb H2 according to a rate law that is first-order each in Ru(II) and H2. The yellow intermediate is shown spectrophotometrically to be a Ru-olefin complex. The following mechanism was proposed" ... 

The three olefinic protons of acrylic acid resonate as a complex higher-order pattern in the chemical shift range from 5.7-6.8 ppm. The most deshielded of these protons is the hydrogen that is cis to the carboxylic acid group, while the geminal proton resonates at higher field. This order of chemical shifts is the reverse of that observed for simple alkenes. 

The olefinic protons of Acrylic Acid Esters appear in the HNMR spectrum as a higher-order ABC pattern in the chemical shift range from 5.6-6.1 ppm. The proton which is trans to the carbonyl group resonates at highest field, the geminal proton resides at slightly lower field, and the hydrogen which is cis to the... 

The ferrocenylbisphosphines 8f—h bearing the amino pendant side chain are unique ligands that effect the rhodium-catalyzed asymmetric hydrogenation of tetrasubstituted olefins 57 (Scheme 2-43) [61], Thus, the hydrogenation of a-aryl-acrylic acid 57a in the presence of a cationic rhodium catalyst coordinated with 8g gives a quantitative yield of carboxylic acid 58a with 98.4% ee. Other tetra-... 

All vinyl polymers are addition polymers. To differentiate the, the homopolymers have been classified by the substituents attached to one carbon atom of the double bone. If the substituent is hydrogen, alkyl or aryl, the homopolymers are listed under polyolefins. Olefin homopolymers with other substituents are described under polyvinyl compounds, except where the substituent is a nitrile, a carboxylic acid, or a carboxylic acid ester or amide. The monomers in the latter cases being derivatives of acrylic acid, the derived polymers are listed under acrylics. Under olefin copolymers are listed products which are produced by copolymerization of two or more monomers. 

C11-15 pareth-12 1,10-Decanediol Dichlorophene Disodium manganous EDTA Distearyidimonium chloride Dodoxynol-8 Ethylenediamine Hydrogenated tallowtrimonium chloride 12-Hydroxystearyl alcohol Maleic acid/acrylic acid copolymer Maleic acid/olefin copolymer, sodium salt Mineral oil Nonoxynol-55 Octoxynol-4 Octoxynol-7... 

Dichioro-5,5-dimethyl hydantoin Didecyidimonium chioride Diisobutyl sodium sulfosuccinate Dimethyiamine Dimethyiaminopropyiamine Dioctyi sodium suifosuccinate Hydrogenated taiiowamine Hydrogenated tallowtrimonium chioride iodine Lithium hypochlorite Maieic acid/acrylic acid copolymer Maleic acid/olefin copolymer, sodium salt Manganese acetate (ous) Mineral oil Montmorillonite... 

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