Benzoin methyl ether

Benzoin methyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether... 

The net result is that the rate of polymerization is lower by about a factor of 10, when polysilanes are compared with conventional photoinitiators such as benzoin methyl ether. 

LR Gold resin 25 mL LR Gold resin and 125 mg benzoin methyl ether mix just prior to use. 

Photochemical, benzoin methyl ether Photochemical, benzoin methyl ether Thermal, AIBN... 

Propensity for free-radical polymerization is most marked for thiocarbonyl chlorofluoride (39). Exposure of the monomer to a sunlamp, especially if benzoin methyl ether is present, leads to rather rapid formation of polymer. Monomer... 

Bendroflumethiazide, benoxaprofen, benzoin methyl ether, Vancomycin 5... 

The nematic LC is the original eutectic mixture of 35% (weight %) 4 (m-octyl oxy)-4-cyanobiphenyl (80CB) and 65% 4/-(n-pentyl)-4-cyanobiphenyl (5CB). The sample is doped with perylene and 2% (mol %) of NIAC, which is acrylate monomer containing the easily reduced l,4 5,8-naphthalenediimide moiety (see Scheme 3). Finally, 0.5% (mol %) of benzoin methyl ether (BME) is added to photoinitiate polymerization of the NIAC. 

Benzoin methyl ether Monomethyl ether of hydrobenzoin (stereoisomers) D 83% 17... 

Membrane-casting Techniques. Uhtil recently, PVC membranes have been exclusively formed by solvent casting techniques but which are not well-suited to the fabrication of ISFET devices. Membrane components in tetrahydrofuran are difficult to manipulate on a micro scale and are prone to absorb atmospheric moisture, thus weakening the adhesion at the sensor-ISFET interface. Che innovation which dispenses with the tetrahydrofuran casting stage is based on an in situ photolysis of the model calciun sensor cocktail admixed with monobutyl methacrylate + benzoyl peroxide + benzoin methyl ether at 340 nm (3). Hie resultant matrix adhered well to the ISFET gate and its potentiate trie response compared favourably with the analogous P and P2-MPMA ISE (Table II). 

Dichloroindium hydride (Cl2InH), generated by the reaction of InCl3 with tributyltin hydride, is also successfully used for the reduction of carbonyl compounds and for the debromination of alkyl bromides.366 This reductant has features such as the chemoselective reduction of functionalized benzaldehydes, chelation-controlled reduction of benzoin methyl ether, and 1,4-reduction of chalcone. The stable carbene and tertiary phosphine adducts of indium trihydride, InH3 CN(Mes)CH=CHN(Mes) and InH3 P(c-G6H11)3, reduce ketones to alcohols (Equation (90)).367... 

Turro and coworkers reported the photolysis of racemic benzoin methyl ether 12 within chiral inductor-immobilized zeolite supercages [55],... 

I (Two polymerizable components) Cyclohexyl methacrylate N-V inylcarbazole Benzoin methyl ether 1.0 ml 0.3 g 0.125 g High—reactivity monomer Low—reactivity monomer Initiator 1.505 1.69... 

II (Lower-index inert component) Cyclohexyl methacrylate Ethylene glycol dimethacrylate Dimethyl suberate Benzoin methyl ether 1.0 ml 0.12 ml 0.25 ml 0.06 g Monomer Crosslinking monomer Inert Initiator 1.505 -1.5 1.4326... 

III (Higher-index inert component) Butyl methacrylate Ethylene glycol dimethacrylate 1-Phenylnaphtha1ene Benzoin methyl ether 0.5 ml 0.5 ml 0.5 ml 0.07 g Monomer Crosslinking monomer Inert Initiator 1.47 1.5 1.666... 

Triallylamine hydrochloride Methacrylate — allyl benzoin methyl ether copolymer Photografting method 0.74 236)... 

Further evidence for Type I cleavage has been obtained by the use of diamagnetic radical scavengers as spin traps for radicals produced on photolysis of benzoin and benzoin methyl ether (18). In both < ses PhCO and PhCHOR (R = H, Me) radicals were trapped and characterised from the e.s.r. spectra of the stable nitroxide radicals formed e.g. 

The efficiencies of benzoin derivatives in promoting the light induced hardening of styrene-containing unsaturated polyester resins have been found to vary considerably (7), benzoin alkyl ethers and a-alkylated benzoins being more reactive than benzoin itself. However, as photoinitiators for the polymerization of bulk methyl methacrylate, benzoin and benzoin methyl ether exhibit comparable efficiencies (20), and this is also indicated for polymerisation of methyl acrylate in tert-butanol (21). The relative photoinitiating efficiencies of benzoin derivatives may be influenced by several factors, some of which will depend on the nature of the monomer system and the environment in which the polymerizations are carried out. 

Photolysis of benzoin and benzoin methyl ether in the presence ctf the phenoxynitrone gave rise to e.sj. signals from both phenoxy and nitroxide radicals. Hydrogen abstraction by benzoin and benzoin ethers would yield radicals of the type... 

The results of spin-trapping experiments 18) also support this view no radicals were trapped on photolysis of benzil in benzene solutions of compounds I and II (see Section II. A. 1) but in methanol solutions of II, CH OH radicals were scavenged, indicating that hydrr en abstraction by photoexcited benzil had occurred 18). Thus the behaviour of benzil in these experiments contrasted markedly with that of benzoin and benzoin methyl ether, described previously. 

As a photoinitiator for the polymerization of bulk methyl methacrylate, benzil was found to be considerably less efficient than benzoin or benzoin methyl ether (20), e,g. at photoinitiator concentrations of 10 M, the polymerization rate observed using benzoin was eight times that observed using benzil, despite the fact that the latter was found to absorb three times as much of the incident radiation (Fig. 1). The photo-initiating efficiency of benzil was improved by a factor of three on addition to the methyl methacrylate of 10% v/v tetrahydrofuran, whereas the same additive had no appreciable effect on rates of benzoin- and benzoin methyl ether-photoinitiated polymerizations direct evidence that photoinitiation by benzil proceeds by a hydrogen abstraction mechanism rather than by fragmentation. 

In the photopolymerization of methacrylamide by benzoin methyl ether, chain-transfer to monomer has been found to be important, and benzalde-hyde is reported to be an inefficient photoinitiator of methyl methacrylate polymerization unless benzophenone and triethylamine are present. Acetophenone has been found to sensitize the cycloaddition of maleic anhydride to 7-oxabicyclo[2.2.1]heptan-5-one-2,3-dicarboxylic anhydride, , a-hydroxy-acetophenone derivatives have been found to be non-yellowing initiators, and h.p.l.c. has been used to determine residual carbonyl photoinitiators in u.v.-cured resins. In the emulsion-polymerization of methyl methacrylate using an aromatic ketone and a continuous or intermittent laser, the former conditions were found to be similar to those under continuous u.v. irradiation. The dependence of the polymerization rate and average chain-length on the absorbance of the initiator used in the photoinitiated polymerization of vinyl monomers has been studied. Interestingly, irrespective of all conditions, maximum conversion is observed when initiator absorbance is 2.51. "... 

The reaction of glycidyl acrylate with a-(2-carboxyethyl)benzoin methyl ether has allowed one to obtain [101] the corresponding acrylic monomer which, upon copolymerization with different amounts of MMA, butyl methacrylate and 2-(V, V-dimethylamino)ethyl methacrylate, gives rise to polymeric photoinitiators, containing side-chain benzoin methylether moieties, for photocurable coatings ... 

It has been found [105,106] in particular that the reaction product [poly (BMEGMA-co-MMA)] derived from glycidyl methacrylate/methyl methacrylate copolymers [poly(GMA-co-MMA)] and a-(2-carboxyethyl)benzoin methyl ether (CEBME) (Scheme 26), although less efficient than CEBME alone in the UV initiated polymerization of styrene, exhibits a markedly enhanced photocrosslinking activity. 

Moreover, poly(a-methylolbenzoin methyl ether acrylate) [poly(MBA)] has been checked in the UV induced polymerization of styrene and compared with poly(AB) and other low-molecular-weight structural models such as benzoin, a-methylol benzoin methyl ether (MBE) and a-methylol ben2 in methyl ether acetate (MBAc) [107]. 

In order to investigate in more detail the relationships between structure and photoinitiation activity in the polymeric systems based on benzoin methyl ether moieties, poly(MBA) and copolymers of MBA with menthyl acrylate [poly(MBA-co-MtA)s] have also been checked as photoinitiators and compared with the homopolymer of ot-vinyloxymethylbenzoin methyl ether and its copolymers with menthyl vinyl ether [poly(MBVE) and poly(MBVE-co-MtVE)s, respectively] [61,84]. 

Low-molecular-weight structural models for both the series of pol5oneric systems, such as MB Ac and a-ethyloxymethyl benzoin methyl ether (MBEE) have also been prepared and tested in terms of photoinitiation activity [61,84],... 

The induction period values for the curing process of the HDDA/BA mixture in the presence of either polymeric or low-molecular-weight photoinitiators based on benzoin methyl ether moieties are found to be quite similar (Table 21) and one order of magnitude shorter than those reported for the systems based on 0-acyloxime moieties (Table 15). 

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