Dicyclopenta diene

Another example of the retention of volatile DA reagents is that of cyclopentadiene in a tandem retro-DA/DA prime reaction [15, 16, 38], This reaction type is the thermal decomposition of a DA adduct (A) and the generation of a diene (generally the initial diene) which is trapped in situ by a dienophile leading to a new adduct (B) [39]. Cyclopentadiene (22) (b.p. 42 °C) is generated by thermolysis of its dimer at approximately 160 °C [40]. An equimolar mixture of commercial crude dicyclopenta-diene (21) and dimethyl maleate was irradiated in accordance with the GS/MW process, in an open reactor, under 60 W incident power, for 4 min (8 x 30 s). The expected adduct 23 was isolated in 40% yield (Scheme 7.1). The isomeric composition of 23 (endo-endoIexo-exo = 65/35) was identical with that obtained under classical conditions from 22 and methyl maleate [41]. The overall yield of this tandem reaction can be increased from pure dimer 21 (61%) and the same tandem reaction has also been reported using ethyl maleate as dienophile [31]. 

Polycycloolefins are prepared by ring opening metathesis polymerization (ROMP) using transition metal catalysts [31], By far the most commonly studied monomer is dicyclopenta-diene (Fig. 1.7). Cycloolefins with high ring strains like norbomenes and their analogs polymerize very fast and the polymerizations are quite exothermic. Metathesis catalyst systems tend to be sensitive to the presence of polar compounds and the polymerization rates... 

G. Wilkinson, Org. Syntheses, 36, 31 (1956). The dicyclopenta-diene used as starting material was dried by passage through a 1 x 12-in. column of activated alumina prior to cracking. 

Bordoloi, . K. Pearce, E. M. "Plastic Sulfur Stabilization by Copolymerization of Sulfur with Dicyclopenta-diene" ADV. CHEM. SER. 1978, 165, 31. 

Arrange the following monomers according to their polymerisability with metathesis catalysts cyclobutene, cyclopentene, cyclooctene, norbornene, dicyclopenta-diene. 

A binder was obtained from an epoxynovolak resin, BPA/DC, BMI, dicyclopenta-diene, Zn acetate and dicumyl peroxide [94]. In a similar composition, BPA/DC prepolymer was used as curing and cyclotrimerization initiators and catalysts, catechol, triethylenediamine, Zn acetate and benzoyl peroxide are mentioned [95], Other compositions contain A1 acetylacetonate and a silicone resin [96], p-toluenesulfonic acid monohydrate and Zn octoate (for rapid curing) [97], or dicumyl peroxide and Zn octoate [98]. 

Bicyclic conjugated diene polymers were anionically prepared by Watanabe [ 1 ] using bicyclo[4.3.0]-2,9-nonadiene and bicyclo[4.3.0]-l,8-nonadiene and products used in high-performance resins. The polymer product of dicyclopenta-diene and 1,3-cyclohexadiene was also prepared by Oshima [2] and used in optical applications. 

A series of mixed bis-Cp dichloro Ti derivatives, previously synthesized by conventional methods,1090 1219 1239-1241 have been used as catalysts for the ring-opening metathesis polymerization of norbornene1242 and dicyclopenta-diene.1243 The catalytic system Cp2TiCl2/MgXR has been employed similarly.1244... 

Selective hydrogenation of aUcenes such as the strained double bond of dicyclopenta-diene is achieved by heating with Pd(OAc)2, r-BusP and HCOOH in TUF. ... 

The copolymerization of ethylene with larger amounts of dicyclopenta-diene with, for example, vanadium trisacetyl acetonate/AIR3 as catalyst, leads to polymers with isolated double bonds. They oxidize at room temperature to insoluble cross-linked films. They can be cross-linked with phenol/ formaldehyde resins and blended with them. 

Excess anhydrous HBr-gas bubbled into 2-thia-l,2-dihydro-endo-dicyclopenta-diene in anhydrous ether until no further precipitation occurs sulfonium salt. Y 81%. P. Wilder, Jr., and L. A. Feliu-Otero, J. Org. Chem. 30, 2560 (1965). 

Ethylene-propylene copolymers (EPDM) are, by their random copolymerization, amorphous in structure and therefore easily halogenated. EPDM has been chlorinated to improve its properties and cocurability with other rubbers. The chlorination was directed toward the termonomer dicyclopenta-diene to form the allylic chloride [28], In this manner, EPDM was chlorinated, and the resulting products had improved properties. 

This expression can be solved analytically, but the result is quite voluminous and not given here. A typical chromatogram is shown in Fig. 1. The dissociation of dicyclopenta-diene is a worked example. " ... 

Metathesis can be catalyzed homogeneously and heterogeneously. The biggest applications of metathesis such as the SHOP process [4] and Phillips Triolefin process use heterogeneous catalysts. Norbornene (Norsorex by CdF Chimie), cyclooctene (Vestenamer by Hiils AG), and dicyclopenta-diene (Hercules) practice homogeneous catalysis. 

In the polymerization reaction, the cycloolefins proved to have some peculiarities, that were closely related to the stability of the corresponding ring [6]. Thus, small strained rings, such as those in cyclopro-pene, cyclobutene, and cyclopentene, are easily polymerizable, even under mild conditions. Similar thermodynamic behavior is encountered in strained polycyclic olefins such as norbornene, dicyclopenta-diene, and norbornene-like monomers. In contrast, cyclohexene is not easily polymerized, and the polymerizability of larger rings decreases as the ring size increases [171]. 

DCPD built into UPR enhanced the degree of drying of the coating surface and their Persoz pendulum hardness (Table 16). Comparable properties could be achieved for UPRs based on propylene glycol, but the use of dicyclopenta-diene is more effective from the economical point of view. 

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