Dicyclopentadiene oxidation

Sulfur Polymer Cement. SPC has been proven effective in reducing leach rates of reactive heavy metals to the extent that some wastes can be managed solely as low level waste (LLW). When SPC is combined with mercury and lead oxides (both toxic metals), it interacts chemically to form mercury sulfide, HgS, and lead sulfide, PbS, both of which are insoluble in water. A dried sulfur residue from petroleum refining that contained 600-ppm vanadium (a carcinogen) was chemically modified using dicyclopentadiene and oligomer of cyclopentadiene and used to make SC (58). This material was examined by the California Department of Health Services (Cal EPA) and the leachable level of vanadium had been reduced to 8.3 ppm, well below the soluble threshold limit concentration of 24 ppm (59). 

Dicyclopentadiene (50 g, 0.38 mole) is dissolved in 100 ml of anhydrous ether. Platinum oxide (0.25 g) is added, and the mixture is hydrogenated in a Parr apparatus at an initial pressure of 50 psi. Initially the reaction mixture becomes warm. The absorption of 2 mole equivalents of hydrogen takes 4-6 hours. The mixture is filtered by suction to remove the catalyst, and the filtrate is distilled at atmospheric pressure through a short fractionating column. 

The 1,3-dipolar cycloaddition reactions of nitrile oxides to unsymmetrically substituted norbomenes (243) and to dicyclopentadiene and its derivatives (244) proceed with complete stereoselectivity. The approach of the dipole takes place exclusively from the exo-face of the bicycloheptane moiety, generally... 

Biological. Cyclopentadiene may be oxidized by microbes to cyclopentanone (Dugan, 1972). Chemical/Physical. Dimerizes to dicyclopentadiene on standing (Windholz et al., 1983). 

The diacetate of 711 has also been produced in stereoselective fashion via a route beginning with dicyclopentadiene (Scheme LXXVI) Ketone 712 was transformed into dimethylated alcohol 713 whose ozonolysis provided 714. Following Jones oxidation, decarboxylation with concomitant introduction of a double bond was realized by application of Kochi s prowdure. A lengthy quence of steps to adjust functionality led up to annulation by a modified Wichterle sequence. The conversion of 715 to 716 was accomplish by standard reactions. 

Emrick and Coughlin et al. reported on the synthesis of cadmium selenide-polymer composites. A vinylbenzyl-derivatized phosphine oxide was ph-ysisorbed onto cadmium selenide particles. Subsequent reaction with RUCI2 (PCy3)2(CHPh) or RuCl2(NHC)(PCy3)(CHPh) (NHC= 1,3-dimesityhmidazol-2-ylidene) followed by addition of cyclooctene, 7-oxanorborn-5-ene-2,3-dicarboxylic anhydride, dicyclopentadiene or N-methyl-7-oxanorborn-5-... 

The cyclopent-2-enone required for the photodimerisation is prepared by the hydrolysis and oxidation of 3-chlorocyclopentene, which is obtained by the low temperature addition of hydrogen chloride to cyclopentadiene. The latter is obtained by heating dicyclopentadiene. This depolymerisation is an example of a reverse (or retro) Diels-Alder cycloaddition reaction the diene readily reforms the dicyclopentadiene on standing at room temperature. 

The first structure type to be established for a hexadiene radical cation was one in which cleavage is achieved without bonding, i.e. a representative of the dissociative mechanism. Dicyclopentadiene and several derivatives can be oxidized to radical cations (137) in which one of the bonds linking the monomer units is cleaved. The unique spin density distribution of 137 is reflected in an unmistakable polarization pattern [386-389]. 

Of great industrial interest are the copolymers of ethene and propene with a molar ratio of 1/0.5, up to 1/2. These EP-polymers show elastic properties and, together with 2-5 wt% of dienes as third monomers, they are used as elastomers (EPDM). Since they have no double bonds in the backbone of the polymer, they are less sensitive to oxidation reactions. As dienes, ethylidenenorbomene, 1,4-hexadiene, and dicyclopentadiene are used. In most technical processes for the production of EP and EPDM rubber in the past, soluble or highly disposed vanadium components are used [69]. Similar elastomers can be obtained with metallocene/MAO catalysts by a much higher activity which are less colored [70-72]. The regiospecificity of the metallocene catalysts toward propene leads exclusively to the formation of head-to-tail enchainments. The ethylidenenor-bornene polymerizes via vinyl polymerization of the cyclic double bond and the tendency to branching is low. The molecular weight distribution of about 2 is narrow [73]. 

R = CH3, CH2SiMe3),96 VO(CH2SiMe3)3, [(Me3CCH2)3V]2(/J,-N2),97 and [V(mes)3(THF)] are all isolable. The latter is a convenient starting material because it is easily prepared and reacts readily with protic sources such as a-amino acids.98 Unstable alkyls are present in the solutions of vanadium oxides or halides and A1 alkyls,99 which are used in the Ziegler-Natta type reaction for the copolymerization of styrene, butadiene, and dicyclopentadiene to give synthetic rubbers. 

A typical procedure is provided by the oxidative cleavage of endo-dicyclopentadiene to the corresponding dialdehyde (Scheme 1). A solution of potassium permanganate (3.41 mmol) and tri-ethylbenzylammonium chloride (141 mmol) in dichloromethane (40 mL) was added dropwise to a solution of en o-dicyclopentadiene (2.27 mmol) in 20 mL of the same solvent maintained at 0-3 C. After the addition, which took 40-50 min, stirring was continued for an additional 30-40 min by which... 

Preparation and Reactivity of [[CpMo(CO)j 2]. [ CpMo(CO)3 2] can be prepared from the reaction between [Mo(CO)6] and dicyclopentadiene at 110 to 120 °C however, this is only really effective for small scale preparations. Better yields are obtained from the reaction between [Mo(CO)3(NCMe)3] with C5H6 monomer or through oxidation of [CpMo(CO)3] with iron (111) sulfate. These latter routes are particularly effective for substituted cyclopentadienyls and indenyl. 

DICYCLOHEXYLTIN OXIDE see DGV900 DICYCLOPENTADIENE see DGWOOO DICYCLOPENTADIENYLDICHLOROTITANIUM see DGW200... 

The housanes 80a,b are also oxidized by PET, but are more reluctant to rearrange, results illustrating the intriguing chemical fate of radical cations derived from dicyclopentadienes and their isomers. In continuation of their investigation, Adam et al. [239] studied oxidation of 2,3-diazabicyclo[2.2.1]hept-2-enes, 82a-d,... 

Limonene is oxidized regioselectively by PBA (Eq. 8) and stereoselectivity can be observed for endo- and exo-dicyclopentadienes. ... 

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