Hydrogenation of dicyclopentadiene

V.M. Gryaznov, M.M. Ermilova, S.I. Zavodchenko, and M.A. Gordeeva, Hydrogenation of dicyclopentadiene (tricyclo[5.2.1.02,6]-deca-3,8-diene) on membrane catalysts from palla-... 

The role of transition metal hydrides has been reviewed and a comparison between gas-phase, liquid-phase and electrochemical hydrogenation has appeared . Laser radiation of Fe(CO)s photocatalyses the gas phase hydrogenation of ethylene(10-70 C, 1-2.4 atm) with quantum yields up to 170 . Selective hydrogenation of dicyclopentadiene (1) to (2) without formation of (3) is achieved via the [RhCl(PPh3)3] catalysed reduction of complex (4) . The new hydride [ThHj(MegSiR2)] (R = Bu,... 

A recent patent describes the synthesis and catalytic use of Al-containing TUD-1 materials. Some of the reactions demonstrated inclnde hydrogenation of mesitylene (Pt as active metal) and dehydration of 1-phenyl-ethanol to styrene. Several other conceptnal reactions were also described, amongst others the Diels-Alder reaction of crotonaldehyde and dicyclopentadiene and the amination of phenol with ammonia. 

The carbon skeleton of dicyclopentadiene must be the same as that of its hydrogenation product, and dicyclopentadiene must contain two double bonds, since 2 mol of hydrogen are consumed in its hydrogenation (C10H12 ------- C10H16). 

The only practical laboratory preparation of cyclopentadiene is by the depolymerization of dicyclopentadiene.3 4-6 6 3-Chloro-cyclopentene has been prepared by the addition of hydrogen chloride to cyclopentadiene.2 7 8 9 10... 

Since this reaction is a unimolecular example of the selective hydrogenation of an alkene mixture, the successful saturation of the less-substituted double bond should take place most readily over those catalysts that are most effective for the preferential saturation of one olefin in a mixture. Ruthenium has not been used extensively for such hydrogenations, but P-2 Ni(B) has been effective in promoting the selective hydrogenation of one of the double bonds in 46, methylene norbornene (49) (Eqn. 15.30), dicyclopentadiene (50) (Eqn. 15.31), and 2-methyl-1,5-hexadiene (51) (Eqn. 15.32).6 9,80,81... 

While our studies for identification of the active/selective phase continues, in a parallel effort, we have conducted some experiments to assess the role of dicyclopentadiene, one of the intermediates proposed in the literature [7]. The objective behind this phase of the study was to examine the routes that originate from dicyclopentadiene and result in phthalic anhydride versus maleic anhydride formation. The catalyst used in this set of experiments was vanadium pentoxide that was pre-reduced in situ at 400 °C with hydrogen. 

P-2 Nickel boride shows a remarkable ability to selectively hydrogenate the strained double bond of norbornene. Thus hydrogenation of 5-methylenenor-bornene (1) and of the endo-dicyclopentadiene (3) give essentially quantitative yields of the dihydro derivatives (2) and (4), respectively.8... 

Ni boride (obtained from sodium borohydride reduction of Ni acetate in ethanol) exhibits sensitivity to substitution on the double bond, and to strained double bonds , and hence is useful for selective half-hydrogenation of dienes. Ni boride selectively hydrogenates the strained double bond of norbonene and dicyclopentadiene. Thus, a synthesis of 13-santalene involves the selective saturation of the endocyclic double bond of 7 over Ni boride, to afford 8 in 98% yield ... 

Allylamine is formed and reacts with 1,3-propanediamine to give 2-ethylhexa-hydropyrimidine, 25, which is dehydrogenated to 24 25 is efficient for selective hydrogenation of dienes such as dicyclopentadiene ... 

The use of dicyclopentadiene at lower concentrations (5 and 10% w/w) has been examined. These mixtures were heated at 140 °C for 3 hr. In both cases only trace amounts of hydrogen sulfide were evolved and brittle products were obtained. 

Preparation of Modified Materials. Materials were prepared by heating the Thiokol or olefin (25% w/w) with purified sulfur at 140 or 170 °C for 3 hr in a nitrogen atmosphere. In the case of dicyclopentadiene, proportions of 5, 10, and 25% w/w were used. Products were poured into pre-heated (40-50 °C) glass dishes and allowed to cool in a desiccator. Liberated hydrogen sulfide from the reaction was trapped in cadmium acetate, and the precipitated cadmium sulfide was determined iodo-metrically. 

Large amounts of cyclopentene occur in the cracked naphtha Cs fraction (see also Section 24.3). In addition, cyclopentadiene and dicyclopentadiene are also present in the Cs fraction, and both of these can be converted to cyclopentene. On the other hand, cyclooctene is obtained by hydrogenation of cyclooctadiene, which is the dimerization product of butadiene. 

Cyclopentene is a relatively inexpensive compound which is obtained by thermal cracking of dicyclopentadiene and further hydrogenation. Its polymerization has been widely studied ... 

If the reaction is carried out at 115 °C in alcohol solvents, the acetal of the dialdehyde is obtained. Partial hydrogenation of the dicyclopentadiene, and thereby formation of monool, was hardly observed. 

Cyclic Polyolefins (GPO) and Gycloolefin Copolymers (GOG). Japanese and European companies are developing amorphous cycHc polyolefins as substrate materials for optical data storage (213—217). The materials are based on dicyclopentadiene and/or tetracyclododecene (10), where R = H, alkyl, or COOCH. Products are formed by Ziegler-Natta polymerization with addition of ethylene or propylene (11) or so-called metathesis polymerization and hydrogenation (12), (101,216). These products may stiU contain about 10% of the dicycHc stmcture (216). 

Dicyclopentadiene (24) [77-73-6] is an inexpensive raw material for hydrocyanation to (25), a mixture of l,5-dicarbonittile [70874-28-1] and 2,5-dicarbonittile [70874-29-2], then subsequent hydrogenation to produce tricyclodecanediamine, TCD diamine (26). This developmental product, a mixture of endo and exo, cis and trans isomers, is offered by Hoechst. 

Dicyclopentadiene can be hydrogenated conveniently over a platinum catalyst in a Parr apparatus. The tetrahydro product is used in the synthesis of adamantane (Chapter 15, Section I). 

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. 

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