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Showing papers on "Benzophenone published in 1982"



Journal ArticleDOI
TL;DR: In this paper, the reaction of NaNO2 in acidic solution with thiocarbonyl compounds has been studied, and the expected oxo compound is obtained as the main product together with 4-(N-nitroso-methylamino)-4,4′-bis (dimethylaminin)-benzophenone at room temperature.

67 citations


Journal ArticleDOI
TL;DR: In this article, the first report of the direct observation of ESR spectra of the randomly oriented benzophenone triplet state at 77 K was presented, where the initial spin polarization and the solvent effects were discussed.

54 citations


Journal ArticleDOI
TL;DR: Laser flash measurements have been made of rate constants and primary radical yields in the reactions of triplet benzophenone with aliphatic and aromatic thiols and with dialkyl and aryl alkyl sulfides as discussed by the authors.
Abstract: Laser flash measurements have been made of rate constants and primary radical yields in the reactions of triplet benzophenone with aliphatic and aromatic thiols and with dialkyl and aryl alkyl sulfides. Reaction with n-pentylthiol in benzene leads mainly to quenching, with k/sub ir/ = 9 x 10/sup 6/ M/sup -1/ s/sup -1/ and radical yield (ketyl) = 0.14; with mesitylene-2 thiol in benzene k/sub ir/ = 7 x 10/sup 8/ M/sup -1/ s/sup -1/ and hydrogen transfer is efficient, radical yield (ketyl) approx. 1.0. In reactions with both p-chlorophenyl ethyl and diisopropyl sulfides, k/sub ir/ increases and radical yield (ketyl) decreases with increasing solvent polarity. Values of k/sub ir/ are higher and those of radical yield (ketyl) are lower for the dialkyl than for the aryl alkyl sulfide. Results are discussed in terms of rapid interaction of the triplet with S, followed by quenching and/or hydrogen transfer. Quenching without hydrogen transfer occurs to a much greater extent with sulfides and aliphatic thiols than with amines.

46 citations


Patent
16 Mar 1982
TL;DR: In this paper, the starting materials for photopolymerizable organopolysiloxane and silicone resins were described and the synthesis methods for preparing these photosensitizers were described.
Abstract: Novel photosensitizers are disclosed which are particularly useful in photopolymerizable organopolysiloxane and silicone resins. The photosensitizers are themselves organopolysiloxanes which contain at least one silicon-bonded benzophenone-containing radical. Synthesis methods are disclosed for preparing these photosensitizers which employ, as starting materials, an alkenyloxy-substituted benzophenone and a silicone compound containing at least one silicon-bonded hydrogen atom.

45 citations


Journal ArticleDOI
TL;DR: The magnetic field effects of photochemical reactions of benzophenone derivatives and dibenzylketone were studied in this article, where the decay rate of the 4.4′-difluorobenzophenone ketyl radical in a sodium dodecylsulfate micelle continued to decrease from 2.9 × 106 s−1 at 0 T to 3.0 × 105 s −1 at 1.34 T.

42 citations


Journal ArticleDOI
TL;DR: The non-exponential decay observed at temperatures between T β and T g is attributed to the intermolecular quenching of benzophenone triplet by carbonyl group in the side chain of PMMA as discussed by the authors.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explored the significance of the reactions involved for conversion processes for coal, which contains significant phenolic functionality, and explored the mechanisms for this characteristic thermal behavior of phenols.
Abstract: The dominant initial products from thermolysis of 1-naphthol in the liquid phase at 400/sup 0/C are 2,2'-binaphthalene-1,1'-diol (2) and 1-tetralone (6).As reaction proceeds, binaphthol 2 undergoes rapid cyclization to dinaphtho(1,2-b:2',1'-d)furan (1), while ketone 6 is more slowly converted ultimately to naphthalene (8). The initial rate of this ring coupling and hydrogen-transfer reaction shows an apparent kinetic order of approx.2.5 in m-terphenyl diluent. In benzophenone solvent, formation of coupled binaphthol 2 is accelerated, but reduced product 6 is replaced by diphenylmethane. Thermolysis of 2-naphthol behaves similarly except that coupling occurs both between C-1 and C-1' to give dinaphtho(2,1-b:1',2'-d)furan (3), preceded by 1,1'-binaphthalene-2,2'-diol (4), and between C-1 and C-3' to give dinaphtho(2,1-b:2',3'-d)furan (5). The major reduction product is 2-tetralone (14). The ratio of (3 + 4)/5 decreases with increasing reaction time. Mechanistic hypotheses for this characteristic thermal behavior of phenols are explored.The significance of the reactions involved for conversion processes for coal, which contains significant phenolic functionality, is discussed.

36 citations


Journal ArticleDOI
TL;DR: The Sciff base derived from glycine ethyl ester and p-chlorobenzaldehyde can be alkylated by the ion-pair extraction method as well as under catalytic liquid-liquid or solid-liquid phase transfer conditions as mentioned in this paper.

35 citations


Journal ArticleDOI
TL;DR: In this article, the authors show that a triplet state, an exciplex (in which triplet benzophenone is the acceptor), a radical pair and a free ketyl radical that has escaped from the micelle are involved in the overall relaxation process of this transient.

23 citations


Journal ArticleDOI
TL;DR: The product composition depends on light intensity as discussed by the authors, and the product composition is also dependent on the light intensity of the alcohol solution and the ambient light intensity, as well as the benzophenone concentration.

Journal ArticleDOI
TL;DR: In this article, the effect of amines on photopolymerization of acrylonitrile sensitized with various sensitizers was investigated in N, N-dimethylformamide at 30°C.
Abstract: Effect of amines on photopolymerization of acrylonitrile sensitized with various sensitizers was investigated in N, N-dimethylformamide at 30°C. Photopolymerizations sensitized with aromatic ketones such as benzophenone (BP), fluorenone (Fl), acetophenone, and Michler's ketone were noticed to be activated by triethylamine (TEA). Diethylamine, tri-n-butylamine, di-n-butylamine, and n-butylamine besides TEA also proved to be effective for the system sensitized with BP or Fl. On the other hand, TEA indicated a negative effect for systems sensitized with α,α′-azobisisobutylonitrile (AIBN), benzoyl peroxide (BPO), benzoin, and 2-tert-butylanthraquinone. Characteristics of the BP—and Fl—amine-sensitized systems were compared with the systems sensitized with AIBN, BPO, and benzoin with respect to kinetics. Contrary to the latter polymerizations following the general kinetics, including the termination of growing chains by mutual deactivation, the former polymerizations were characterized by an elevated susceptibility of the primary radical termination.

Journal ArticleDOI
TL;DR: In this article, the photodegradation of poly(methyl methacrylate) has been investigated by electron spin resonance and viscosity measurements, and a mechanism of protection by benzophenone and 2-hydroxy-4methoxybenzophenone was proposed on the basis of the experimental results.

Journal ArticleDOI
TL;DR: The photoreduction of benzophenone by several substrates has been studied by time-resolved EPR as discussed by the authors, and it is suggested that the experimental observations can be explained by intersystem crossing to a quartet state in the excited ketyl radical.

Journal ArticleDOI
TL;DR: In this article, the solvation of benzophenone ketyl ion in liquid n -propanol at 146 K was investigated by pulse radiolysis and the absorption spectrum was obtained after 50 ns shifts to shorter wavelengths during the first 20 μs.

Journal ArticleDOI
TL;DR: In this article, the effect of a hindered piperidine compound, Bis[2,2,6,6-tetramethyl-4-piperidinyl] sebacate on the photostability and light-stabilizing performance of polypropylene film has been examined using three different light exposure units.
Abstract: The effect of a hindered piperidine compound, Bis[2,2,6,6-tetramethyl-4-piperidinyl] sebacate on the photostability and light-stabilizing performance of hydroxy-substituted benzophenone and anthraquinone compounds in polypropylene film has been examined using three different light exposure units. The stabilizing effects observed were found to be highly dependent on the utraviolet content (300–340 nm) of the light source. In the absence of this utraviolet component the hindered piperidine compound inhibited the photolysis of all the hydroxy-substituted compounds, whereas in its presence no protective effect was observed. In fact, direct absorption of ultraviolet light was found to be totally ineffective in photostabilizing the polymer. The protective effects were associated with the ability of the hindered piperidine compound to destroy the hydroperoxides formed during processing. This was confirmed by the observation of no protective action with unsubstituted benzophenone and anthraquinone through both steady-state and laser flash-photolysis experiments. A further novel protective effect was observed when the hindered piperidine molecule was linked to the anthraquinone chromophore in the 2-position to the carbonyl group. In this case photoprotection is associated with an intramolecular excited-state quenching process.

Journal ArticleDOI
TL;DR: In this article, photo-initiator systems for the polymerization of acrylates, based on a mixture of an aryl ketone and an α,ω-diaminoalkane, have been investigated.

Journal ArticleDOI
TL;DR: In this paper, the synthesis of 5-acylaminomethyl-3-carbamoyl-1H-1,2,4-triazol-1-yl derivatives is described.

Journal ArticleDOI
TL;DR: In this paper, 2-hydroxy-4-methacryloyloxy benzophenone and 4-acetyl-4 acryl-oyl-oxy benzphenone were grafted onto the backbone of polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) by melt processing in the mixer of Brabender Plastic Order.
Abstract: Monomeric ultraviolet stabilizers, 2-hydroxy-4-methacryloyloxy benzophenone and 2-hydroxy-4-acryloyloxy benzophenone were synthesized by a modified process. These reactive UV stabilizers were grafted onto the backbone of polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) by melt processing in the mixer of Brabender Plasticorder. An infrared spectroscopic method was standardized for the quantitative determination of the extent grafting of these additives on the polymer backbone. Grafting of both the additives occurred in the order PS > LDPE > PP. Methacryloxy derivative of benzophenone was found to be more reactive towards the polymers studied than the acryloxy derivative.

Journal ArticleDOI
TL;DR: Phenylytterbium iodide (Ph-Yb-I) has been found to react with benzoyl chloride to give both triphenylcarbinol and benzophenone.
Abstract: Phenylytterbium iodide (Ph–Yb–I) has been found to react with benzoyl chloride to give both triphenylcarbinol and benzophenone. When Ph–Yb–I is added inversely to benzoyl chloride, especially in the presence of FeCl3, the ketone is obtained selectively in modest yields in contrast to the Grignard reaction.

Journal ArticleDOI
TL;DR: Fluorescence quenching experiments indicate that energy transfer occurs from cumene excited at 254 nm to cumene hydroperoxide, which is the main photoproduct of polystyrene as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, a unique application of 19F-n.m.r. spectrometry was presented, where the compounds were determined simultaneously in aqueous dosage forms without the need for sample preparation, using partial proton decoupling and exponential multiplication of the free induction decay with a line-broadening parameter of 12 Hz.

Journal ArticleDOI
TL;DR: In this article, the isolation of benzhydrol and its ether in conjunction with N-formylbenzhydrylamine in the Leuckart reaction of benzophenone is reported; it is postulated that this alcohol is a possible intermediate in the reaction.

Journal ArticleDOI
TL;DR: In this paper, the formation of substituted 3-hydroxy-3-phenylpropiononitriles (II), cinnamonitrile (III), carbinols (VIII), and 3phenylglutaronit riles (V) during the electroreduction of acetophenone, benzaldehyde, and benzophenone in acetonitrile has been studied.
Abstract: The formation of substituted 3-hydroxy-3-phenylpropiononitriles (II), cinnamonitriles (III), 3-phenylpropiononitriles (IV), and 3-phenylglutaronitriles (V) during the electroreduction of acetophenone, benzaldehyde, and benzophenone in acetonitrile has been studied. The factors which influence the distribution of these products and their importance relative to the ‘normal’ reduction products, pinacols (VII) and carbinols (VIII), have been identified; current density, temperature, and water concentration are the most important. The distribution of acetonitrile-derived products is compared with that found when the corresponding cinnamonitriles (III) are electroreduced.

Journal ArticleDOI
TL;DR: In this article, metal phthalocyanineimides of copper, cobalt, nickel, and zinc were synthesized by the reaction of metal PHTHCyanino tetramines with benzophenone tetracarboxylic dianhydride.
Abstract: Poly(metal phthalocyanine)imides of copper, cobalt, nickel, and zinc were synthesized by the reaction of metal phthalocyanino tetramines with benzophenone tetracarboxylic dianhydride. These polymers were characterized by elemental analyses and IR, TGA, and inherent viscosity studies. Noteworthy features of these phthalocyanine polymers are their remarkable thermal and thermooxidative stabilities with char yields at 800°C that range from 78 to 83% in a nitrogen atmosphere. The relative thermal stabilities of these polymers have been evaluated by activation energy measurements.

Journal ArticleDOI
TL;DR: In this article, N-Aminophthalimide (I) reacted with a variety of aromatic aldehydes to give the related arylideneaminophthylimides (III-X), although typical ketones such as acetone and benzophenone did not under the specific conditions employed.

Journal ArticleDOI
TL;DR: In this paper, the formation of 1,2-propadienyllithium was described by treatment of 1-2-propadiene with n-butyllithium in tetrahydrofuran-hexane.

Journal ArticleDOI
TL;DR: In this paper, the isomerization of benzophenone oxime to benzanilide, previously observed to take place in the ion source of a mass spectrometer and attributed to a Beckmann type rearrangement, has been shown to occur by a thermal mechanism prior to ionization.
Abstract: The isomerization of benzophenone oxime to benzanilide, previously observed to take place in the ion source of a mass spectrometer and attributed to a Beckmann type rearrangement of the benzophenone oxime molecule ion, has been shown to occur by a thermal mechanism prior to ionization. Mass spectrometric evidence is supplemented by infrared spectrophotometric examination of solid samples and shows that in the solid state, at room temperature, benzophenone oxime has a lifetime of about 600 h.

Journal ArticleDOI
TL;DR: In this article, measurements of the extent of polymerization have been made for photoinitiated polymerization reactions using consistent conditions and a common monomer, butyl acrylate.
Abstract: Measurements of the extent of polymerization have been made for photoinitiated polymerization reactions using consistent conditions and a common monomer, butyl acrylate. Three radiation wavelengths were used and it was found that in most cases polymerization proceeded in the order 350 > 300 > 254 nm. From the range of photoinitiators studied it was found that those of the benzoin type, undergoing cleavage, promoted reaction faster than the benzophenone type, requiring a hydrogen abstraction mechanism. At 350 nm, those undergoing a cleavage mechanism showed reaction rates following the order of their ultraviolet absorption. A hydrogen donor such as a tertiary amine was necessary for the benzophenone-type initiators. Hydrogen donors tended to have mixed effects on polymerization produced by benzoin-type initiators. From a broad range of hydrogen donors used with benzophenone it was found that aliphatic tertiary amines were the most effective.

Patent
23 Sep 1982
TL;DR: A photopolymerizable composition based on an epoxy compound contains as a curing catalyst a combination of an α-ketosilyl compound with an aluminum compound having at least one organic radical directly bonded to the aluminum atom.
Abstract: A photopolymerizable composition based on an epoxy compound contains as a curing catalyst a combination of an α-ketosilyl compound with an aluminum compound having at least one organic radical directly bonded to the aluminum atom, and further contains as a photosensitizer a benzophenone compound and/or a thioxanthone compound.