Cyclohexene oxide monomer

13C NMR spectroscopy of the reaction mixture is useful not only to determine the presence of coupling products, but also to assign the tacticity of the copolymer product. The solution IR spectrum of poly(cyclohexene carbonate) shows three stretching bands corresponding to vc,0 of the copolymer at 1750 cnr1, and that of 

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The simplest model compound is cyclohexene oxide III. Monomers IV, V and VII represent different aspects of the ester portion of I, while monomers VII and VIII reflect aspects of both the monomer I and the polymer which is formed by cationic ring-opening polymerization. Monomers IV-VII were prepared using a phase transfer catalyzed epoxidation based on the method of Venturello and D Aloisio (6) and employed previously in this laboratory (7). This method was not effective for the preparation of monomer VIII. In this specific case (equation 4), epoxidation using Oxone (potassium monoperoxysulfate) was employed. 

The monomers of styrene oxide, 1,4-cyclohexene oxide, trioxane, and vinyl ether were polymerized at satisfactory rates. However, tetrahydrofuran, e-caprolactone, and cc-methylstyrene could not be polymerized7). 

The evidence in the case of styrene, where both modes of radiation-induced polymerization can be conveniently studied, is quite convincing that reduction of the concentration of water changes the predominating mode of propagation from purely free radical to essentially ionic. Evidence for an ionic propagation initiated by radiation has also been obtained in pure a-methylstyrene (3, 24), isobutylene (12, 32), cyclopenta-diene (5), / -pinene (2), 1,2-cyclohexene oxide (II), isobutyl vinyl ether (6), and nitroethylene (38), although the radical process in these monomers is extremely difficult, if not impossible, to study. 

Further examples for electron acceptor monomers are acrylonitrile [37], diethyl fumarate [39], fumaronitrile [29,30, 38], maleonitrile [38], N-carbethoxymaleimide [29], N,N-diethylaminoethyl methacrylate [39], nitroethylene [10] and iV-ethyl-maleimide [40], As electron donor monomem also are used vinyl alkyl ethers [38, 40], alkyl methacrylate [40], JV-vinyl pyrrolidone [40] and cyclohexene oxide [10]. 

Cyclic monomers such as cyclohexene oxide were readily polymerized upon irradiation of the CT complexes of pyridinium salts whereas spontaneous polymerizations were observed upon mixing with strong electron donating monomers such as butyl vinylether and A-vinyl carbazole. These monomers are known to form CT complexes themselves with electron acceptors which may interfere with the rapid polymerization observed. 

UV irradiation of the resulting prepolymers caused a-scission, and benzoyl and polymer bound electron donating radicals are formed in the same manner as described for the low-molar mass analogues. Electron donating polymeric radicals thus formed may conveniently be oxidized to polymeric carboeations to promote cationic polymerization of cyclic ethers. It was demonstrated that irradiation of benzoin terminated polymers in conjuction with pyridinium salts as oxidants in the presence of cyclohexene oxide makes it possible to synthesize block copolymers of monomers with different chemical natures [75] (Scheme 19). 

Polymerization of some cationically polymerizable monomers like cyclohexene oxide [49], 3,3-bis(chloromethyl)oxetane [50], or 1,3,5-trioxane [51] may be initiated by irradiation with y-rays both in liquid or solid state. 

Cationic organozinc compounds are expected to be good catalysts for ring opening polymerization reactions of epoxides and lactones because the enhanced Lewis acidity (see Lewis Acids Bases) of the zinc center favors its coordination to the monomer. For example, Walker and coworkers have found that the cationic zinc substituted cyclopentadienyl complex [3,5-Me2C6H3CH2CMe2C5H4Zn(TMEDA)]+ [EtB(C6F5)3] is an active initiator species for the polymerization of cyclohexene oxide and e-caprolactone. ... 

To the first category belongs the photochemical formation of carbenhim ions or protonic acids directly in the polymerization medium this field, discussed in Sect. 3.1 and 3.2 has recently been reviewed by Smets at the lUPAC Macronmlecular Sympo-sium2 ) When cyclohexene oxide is used as a monomer the order of reactivities for iodonium or sulphonium salts, giving photochemically protonic acid, depend on the structure of anion MtX in the following way ... 

A number of monomers has already been investigated, e.g., cyclo-pentadiene [86], styrene [89, 93], a-methylstyrene [87, 89, 95], formaldehyde [94], alkyl vinyl ethers [85, 89], isobutene [84], nitroethylene [96] and also the cyclic monomer cyclohexene oxide [97]. For most of these reliable quantitative data is now available. Because the number of active centres formed is small all of these systems are particularly susceptible to traces of impurities, especially water and spurious basic materials. Indeed much of the early data [82, 83] from 7-ray initiation was confused because of the use of relatively wet monomers. Furthermore the intrinsic lifetime of a free cation is limited because the... 

Cyclohexene oxide is useful as a monomer in polymerization and the coating industry. It is used in the synthesis of alicyclic molecules used in pesticides, pharmaceuticals, perfumery, and dyestuffs, and as a monomer in polymerization with CO2... 

As compared to vinyl monomers, relatively few studies of ringopening polymerization Induced by high energy radiation have been reported In the liquid state ( 7). Easily the best documented example Is the polymerization of 1,2-cyclohexene oxide described by Cordlschl, Ifele, and their co-workers (8-10). These authors found that the polymerization of this epoxide displays many of the characteristics previously observed for the radlatlon-lnduced cationic polymerization of unsaturated monomers, Including the great sensitivity to water (.3) and the strongly retarding effect of ammonia (11). 

A detailed study of mechanisms both of photodecomposition of triarylsul-fonium salts to yield Bronsted acids and of catalysis of cationic polymerization of representative monomers—styrene oxide, cyclohexene oxide, tetrahydrofuran (THF), and 2-chloroethyl vinyl ether—was reported in 1979 by Crivello and Lam [14]. Crivello [15] and Green et al. [16] provided further reviews shortly thereafter. The mechanisms of photodecomposition of a variety of initiators for free radical photopolymerization, including onium salts, were compared by Vesley [17] in 1986. A review, similar in scope, but providing more mechanistic detail was also published in 1986 by Timpe [10a]. An updated coverage of aspects of this chemistry has been provided by the same author in his review of photoinduced electron transfer polymerization [10b]. 

Thus, the determined composition of lithium amide 4 in the initial state in presence of excess of the corresponding diamine has been used in combination with kinetics to determine the composition of the activated complexes in cyclohexene oxide deprotonation. It appears that an activated complex is built from one lithium amide monomer and one epoxide molecule [18]. These results suggest that we are dealing with the TS structures (5)-TS and (R)-TS shown in Scheme 7 leading to the (5)- and (/ )-enantiomer of the allylic alcohol 3, respectively. 

Carbocations generated in this way can add directly to appropriate monomers (e.g., tetrahydrofuran, cyclohexene oxide, n-butyl vinyl ether) or can form Bronsted acids by abstracting hydrogen from surrounding molecules. This method, which is commonly referred to as free-radical-promoted cationic polymerization, is quite versatile, because the user may rely on a large variety of radical sources. Some of them are compiled in Table 10.9. 

The functionalisation of hydrocarbon feedstocks is a key value-creating step in the chemical industry. Selective oxidation reactions, such as the epoxidation of alkenes, are a substantial basis of fine chemical production [98]. For example, propylene oxide is used industrially in the production of polyurethane and propylene glycol [99], ethylene oxide (EO) is used to produce ethylene glycol and various ethoxylates [100], while cyclohexene oxide is used as an alicyclic chemical intermediate in the production of pesticides, pharmaceuticals, perfumes and dyes [101] or as a monomer in photoreactive polymerisation [102]. 

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