The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Jan Szymanowski - One of the best experts on this subject based on the ideXlab platform.
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2-Hydroxybenzophenone UV-absorber containing 4,4,5,5-tetramethylimidazolidine fragment
Polymer Degradation and Stability, 2001Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:2-Hydroxy-4-[(2,4,4,5,5-pentamethylimidazolidin-2-yl)methoxy]benzophenone (4)-2-Hydroxybenzophenone UV-absorber containing 4,4,5,5-tetramethylimidazolidine fragment was obtained in the reaction of 4-(2-oxopropoxy)-2-Hydroxybenzophenone (3) with 2,3-diamino-2,3-dimethylbutane (2).
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2 Hydroxybenzophenone uv absorbers containing 2 2 6 6 tetramethylpiperidine hals group benzoylation of corresponding phenol derivatives
Polymer Degradation and Stability, 2000Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract Phenol derivatives containing 2,2,6,6-tetramethylpiperidine group were successfully benzoylated with both benzoyl chloride in the presence of aluminium chloride and benzotrichloride in aqueous sodium hydroxide solution. The 2-Hydroxybenzophenone UV-absorbers bearing light stabilizing fragment — 2,2,6,6-tetramethylpiperidine nucleus — were synthesized in this way.
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2-Hydroxybenzophenone UV-absorbers containing 2,2,6,6-tetramethylpiperidine (HALS) group — benzoylation of corresponding phenol derivatives
Polymer Degradation and Stability, 2000Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract Phenol derivatives containing 2,2,6,6-tetramethylpiperidine group were successfully benzoylated with both benzoyl chloride in the presence of aluminium chloride and benzotrichloride in aqueous sodium hydroxide solution. The 2-Hydroxybenzophenone UV-absorbers bearing light stabilizing fragment — 2,2,6,6-tetramethylpiperidine nucleus — were synthesized in this way.
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A convenient modification of 2-HydroxybenzophenoneUV-absorbers
Polymer Degradation and Stability, 1999Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract 2-Hydroxybenzophenone derivatives ( 3a–f ) were synthesized from 2,4-diHydroxybenzophenone ( 1a ) using 4- O -alkylation of the 4-hydroxyl group with 1-(2-chloroethyl)-2,2,6,6-tetramethylpiperidine ( 2a ) and from the carboxyl derivatives of 2-Hydroxybenzophenone ( 1b–e ) using the esterification as well as transesterification reactions with the hydroxyl derivatives of 2,2,6,6-tetramethylpiperidine ( 2b–d ) .
Jerzy Zakrzewski - One of the best experts on this subject based on the ideXlab platform.
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2-Hydroxybenzophenone UV-absorber containing 4,4,5,5-tetramethylimidazolidine fragment
Polymer Degradation and Stability, 2001Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:2-Hydroxy-4-[(2,4,4,5,5-pentamethylimidazolidin-2-yl)methoxy]benzophenone (4)-2-Hydroxybenzophenone UV-absorber containing 4,4,5,5-tetramethylimidazolidine fragment was obtained in the reaction of 4-(2-oxopropoxy)-2-Hydroxybenzophenone (3) with 2,3-diamino-2,3-dimethylbutane (2).
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2 Hydroxybenzophenone uv absorbers containing 2 2 6 6 tetramethylpiperidine hals group benzoylation of corresponding phenol derivatives
Polymer Degradation and Stability, 2000Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract Phenol derivatives containing 2,2,6,6-tetramethylpiperidine group were successfully benzoylated with both benzoyl chloride in the presence of aluminium chloride and benzotrichloride in aqueous sodium hydroxide solution. The 2-Hydroxybenzophenone UV-absorbers bearing light stabilizing fragment — 2,2,6,6-tetramethylpiperidine nucleus — were synthesized in this way.
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2-Hydroxybenzophenone UV-absorbers containing 2,2,6,6-tetramethylpiperidine (HALS) group — benzoylation of corresponding phenol derivatives
Polymer Degradation and Stability, 2000Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract Phenol derivatives containing 2,2,6,6-tetramethylpiperidine group were successfully benzoylated with both benzoyl chloride in the presence of aluminium chloride and benzotrichloride in aqueous sodium hydroxide solution. The 2-Hydroxybenzophenone UV-absorbers bearing light stabilizing fragment — 2,2,6,6-tetramethylpiperidine nucleus — were synthesized in this way.
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A convenient modification of 2-HydroxybenzophenoneUV-absorbers
Polymer Degradation and Stability, 1999Co-Authors: Jerzy Zakrzewski, Jan SzymanowskiAbstract:Abstract 2-Hydroxybenzophenone derivatives ( 3a–f ) were synthesized from 2,4-diHydroxybenzophenone ( 1a ) using 4- O -alkylation of the 4-hydroxyl group with 1-(2-chloroethyl)-2,2,6,6-tetramethylpiperidine ( 2a ) and from the carboxyl derivatives of 2-Hydroxybenzophenone ( 1b–e ) using the esterification as well as transesterification reactions with the hydroxyl derivatives of 2,2,6,6-tetramethylpiperidine ( 2b–d ) .
Hiroyuki Nakazawa - One of the best experts on this subject based on the ideXlab platform.
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simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption gas chromatography mass spectrometry
Journal of Chromatography A, 2008Co-Authors: Migaku Kawaguchi, Rie Ito, Hidehiro Honda, Naoyuki Endo, Noriya Okanouchi, Koichi Saito, Yasuo Seto, Hiroyuki NakazawaAbstract:A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-diHydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4'-methylbenzophenone (BP-10), 2-Hydroxybenzophenone (2OH-BP), 3-Hydroxybenzophenone (3OH-BP) and 4-Hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The detection limit is 0.5-2 ng L(-1) (ppt) for the seven BPs. The method shows good linearity and the correlation coefficients are equal to or higher than 0.990 for all the analyte. The average recoveries of BPs range from 102.0 to 128.1% (RSD<15.4%, n=6). Trace amounts of BPs in river water samples were determined by the present method.
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Simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.
Journal of chromatography. A, 2008Co-Authors: Migaku Kawaguchi, Rie Ito, Hidehiro Honda, Naoyuki Endo, Noriya Okanouchi, Koichi Saito, Yasuo Seto, Hiroyuki NakazawaAbstract:A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-diHydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4'-methylbenzophenone (BP-10), 2-Hydroxybenzophenone (2OH-BP), 3-Hydroxybenzophenone (3OH-BP) and 4-Hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The detection limit is 0.5-2 ng L(-1) (ppt) for the seven BPs. The method shows good linearity and the correlation coefficients are equal to or higher than 0.990 for all the analyte. The average recoveries of BPs range from 102.0 to 128.1% (RSD
Norman S. Allen - One of the best experts on this subject based on the ideXlab platform.
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Interactions in the thermal and light stabilising action of novel aromatic phosphites with a 2-Hydroxybenzophenone and hindered piperidine stabiliser in polyolefin films
Polymer Degradation and Stability, 1995Co-Authors: Norman S. Allen, Ricardo Acosta Ortiz, Graeme J. AndersonAbstract:Abstract The interactions of two novel phosphite stabilisers with a commercial polymeric hindered piperidine stabiliser, Chimassorb 944, and a 2-hydroxy-4-n-ctoxybenzophenone stabiliser, Cyasorb UV 531, have been examined in the thermal and photooxidation of polypropylene and high density polyethylene films using FTIR spectroscopy. The two structures are based on a bis-hindered phenolic moiety coupled to a 2-Hydroxybenzophenone and a 4-amino-tetramethylpiperidine (3) chromophore. Thermal oven ageing and photooxidation of the polyolefin films showed that the hindered piperidine phosphite (phosphoramide) is synergistic over a wide concentration ratio with both commercial stabilisers. The only exception is in polyethylene with the Chimassorb 944, wherein the latter shows poor solubility in polyethylene. Generally, the phosphoramide is found to be more effective as a thermal antioxidant than as a UV antioxidant. The 2-Hydroxybenzophenone phosphite was generally ineffective as a light stabiliser and exhibited unusual S-shaped profiles in combination with both the commercial stabilisers, suggesting the involvement of two distinct processes. With Cyasorb UV 531 the antagonistic/synergistic patterns were reversed from polypropylene to polyethylene. With Chimassorb 944 strong synergism is observed at high phosphite ratios while antagonism is prevalent at low ratios. In general, one interesting feature of the results is that the thermal and UV effects often exhibit a similar behaviour.
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Comparison of the thermal and light stabilising action of novel aromatic phosphites substituted with 2-Hydroxybenzophenone and hindered piperidine moieties in polyolefins
Polymer Degradation and Stability, 1994Co-Authors: Norman S. Allen, Ricardo Acosta Ortiz, Graeme J. Anderson, Manji SasakiAbstract:Abstract Three novel phosphite stabilisers have been synthesised and characterised and their thermal and photochemical effectiveness examined in polyethylene and polypropylene films. Two structures are based on a bis-hindered phenolic moiety coupled to a 2-Hydroxybenzophenone (2) and a 4-amino-tetramethylpiperidine (3) chromophore. The third is a tris-2-Hydroxybenzophenone based phosphite (4). Thermal oven aging and thermal analysis on the polymer films showed that the hindered piperidine phosphite is an effective primary and secondary antioxidant compared with the 2-Hydroxybenzophenone derivatives. These results are consistent with its ability to inhibit the formation of hydroperoxides during thermal aging. The 4-aminopiperidine phosphite compound is also an effective light stabiliser for polypropylene. The 2-Hydroxybenzophenone derivative (2) was ineffective as a light stabiliser in all cases and antagonised the effectiveness of a commercial polymeric hindered piperidine stabiliser (Chimassorb 944). The tris-2-Hydroxybenzophenone phosphite compound (4), however, was more effective as a light stabiliser in polypropylene than in polyethylene. Both mass spectrometry and thermal analysis indicated initial fragmentation resulting in the loss of the 2-Hydroxybenzophenone and 4-aminopiperidine stabiliser moieties from the phosphorus atom. the importance of combining different stabiliser moieties within the same structure in terms of performance is discussed.
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Thermal and photooxidative behaviour of novel 4-substituted alicyclic amino-2-Hydroxybenzophenone stabilizers in polypropylene and high density polyethylene films
Polymer Degradation and Stability, 1992Co-Authors: Norman S. Allen, Michele Edge, S. Conway, D.a. Doyle, E.m. Howells, K. Kikkawa, M. Minagawa, T. SekiguichiAbstract:The thermal and photooxidative stabilization activities of four light stabilizers based on 2-Hydroxybenzophenone with alicyclic amine groups substituted in the 4-position have been examined and compared with those of 2-hydroxy-4-n-octoxybenzophenone (HOBZ) in polypropylene and high density polyethylene (HDPE) films at 0·1% w/w concentration infra-red absorption spectroscopy. From both carbonyl index and embrittlement times, both alkylpiperazine derivatives were found to be ineffective on exposure to QUV irradiation, whereas the propoxymorpholinyl and the hindered piperidine compounds were found to be more effective than HOBZ. All the stabilizers were synergistic with the commercial hindered phenolic antioxidant, Irganox 1010, especially the HOBZ. On the thermal ageing all the light stabilizers behaved as antioxidants, including the HOBZ. However, the hindered piperidine derivative was the most effective, exhibiting a stabilizing effect close to that of the Irganox 1010. In the presence of the Irganox 1010 weak antagonism was observed, with the HOBZ exhibiting the most effective stabilization. In HDPE the effects were different on irradiation, with all the 4-substituted amino benzophenones being effective. In this case the 4-amino hindered piperidine stabilizer was more effective than HOBZ. In the presence of Irganox 1010 strong synergism is common except for the bis-N,N-octylpiperazine derivative. On oven ageing all the stabilizers exhibited antioxidant behaviour with the 4-amino-piperidine derivative being the most effective. The antioxidant effect of Irganox 1010 was not impaired in HDPE apart from that with the propoxy-morpholino derivative. The steric hindrance, molecular size and oxygen scavenging ability of the cyclic amine are all concluded to be important factors in controlling the antioxidant behaviour of the stabilizer with hydroperoxides playing a key role in the latter case. The results also demonstrate the importance of the ortho hydrogen bonded hydroxyl group in 2-Hydroxybenzophenones as an active chain-breaking donor in photostabilization and not UV absorption. It is further concluded that the results show the potential for the development of a single stabilizer entity which will behave as an effective photothermal antioxidant.
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Synthesis and thermal and photo-oxidative behaviour of novel 4-substituted alicyclic amino-2-Hydroxybenzophenone stabilizers in polypropylene films
European Polymer Journal, 1991Co-Authors: Norman S. Allen, Michele Edge, S. Conway, D.a. Doyle, E.m. Howells, K. Kikkawa, M. Minagawa, T. SekiguichiAbstract:Abstract Four light stabilizers have been synthesized and characterized, based on the substitution of an alicyclic amine group into the 4-position of 2-Hydroxybenzophenone. The compounds prepared were bis-N,N′-alkylpiperazines, N-propoxymorpholinyl and 4-amino-2,2,6,6-tetramethylpiperidinyl derivatives. The thermal and photo-oxidative stabilization activities of the three compounds have been examined and compared with those of 2-hydroxy-4-n-octoxybenzophenone (HOBZ) in polypropylene film at 0.1% w/w concentration using i.r. absorption spectroscopy, hydroperoxide analysis and yellowness index. Through both carbonyl index and embrittlement times, both alkylpiperazine derivatives were found to be ineffective on exposure to QUV irradiation but both the propoxymorpholinyl and the hindered piperidine compounds were found to be more effective than HOBZ. These stabilizing effects followed closely their ability to inhibit hydroperoxide formation before and during oven ageing. With the commercial hindered phenolic antioxidant, Irganox 1010, all the stabilizers were synergistic, especially HOBZ. On thermal ageing, all the light stabilizers including HOBZ behaved as antioxidants. The hindered piperidine derivative was the most effective, exhibiting a stabilizing effect close to that of the Irganox 1010. In the presence of Irganox 1010, weak antagonism was observed with HOBZ exhibiting the most effective stabilization. Both piperazine derivatives discoloured markedly on irradiation while the alkylmorpholinyl exhibited an initial photobleaching effect. The steric hindrance, molecular size and oxidizability of the cyclic amine are all concluded to be important factors in controlling the antioxidant behaviour of the stabilizer, with hydroperoxides playing a key role in the latter case. The results also demonstrate the importance of the ortho hydrogen bonded hydroxy group in 2-Hydroxybenzophenones as an active chain-breaking donor and not the extinction coefficients. It is further concluded that the results show the potential for the development of a single stabilizer entity which will behave as an effective photothermal antioxidant.
Mark E Light - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, spectroscopic characterization and structural studies of mixed ligand complexes of Sr(II) and Ba(II) with 2-Hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or β-diketones Crystal structure of 2-HOC6H4C(O)C6H5
Inorganica Chimica Acta, 2006Co-Authors: Keerti Saraswat, John E Drake, Raju Ratnani, R.n. Prasad, Michael B. Hursthouse, Mark E LightAbstract:Reactions of Sr(II) and Ba(II) chlorides with 2-Hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or beta-diketones in 1:1:1 molar ratios have resulted in the formation of mixed ligand complexes of the type [MLL'(H2O)(2)] (M = Sr(II) or Ba(II); HL = 2-Hydroxybenzophenone and HL' = salicylaldehyde, 2-hydroxyacetophenone, 2-hydroxypropiophenone, pentane2,4-dione, 1-phenylbutane-1,3-dione or 1,3-diphenylpropane-1,3-dione). These complexes have been characterized by elemental analyses, TLC, IR and H-1 NMR spectroscopy.
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Synthesis, spectroscopic characterization and structural studies of mixed ligand complexes of Sr(II) and Ba(II) with 2-Hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or β-diketones: Crystal structure of 2-HOC6H4C(O)C6H5
Inorganica Chimica Acta, 2006Co-Authors: Keerti Saraswat, John E Drake, Raju Ratnani, R.n. Prasad, Michael B. Hursthouse, Mark E LightAbstract:Abstract Reactions of Sr(II) and Ba(II) chlorides with 2-Hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or β-diketones in 1:1:1 molar ratios have resulted in the formation of mixed ligand complexes of the type [MLL′(H2O)2] (M = Sr(II) or Ba(II); HL = 2-Hydroxybenzophenone and HL′ = salicylaldehyde, 2-hydroxyacetophenone, 2-hydroxypropiophenone, pentane-2,4-dione, 1-phenylbutane-1,3-dione or 1,3-diphenylpropane-1,3-dione). These complexes have been characterized by elemental analyses, TLC, IR and 1H NMR spectroscopy.
