- Concerted Multiproton-Multielectron Transfer for the Reduction of O2to H2O with a Polyoxovanadate Cluster
-
The concerted transfer of protons and electrons enables the activation of small-molecule substrates by bypassing energetically costly intermediates. Here, we present the synthesis and characterization of several hydrogenated forms of an organofunctionalized vanadium oxide assembly, [V6O13(TRIOLNO2)2]2-, and their ability to facilitate the concerted transfer of protons and electrons to O2. Electrochemical analysis reveals that the fully reduced cluster is capable of mediating 2e-/2H+ transfer reactions from surface hydroxide ligands, with an average bond dissociation free energy (BDFE) of 61.6 kcal/mol. Complementary stoichiometric experiments with hydrogen-atom-accepting reagents of established bond strengths confirm that the electrochemically established BDFE predicts the 2H+/2e- transfer reactivity of the assembly. Finally, the reactivity of the reduced polyoxovanadate toward O2 reduction is summarized; our results indicate a stepwise reduction of the substrate, proceeding through H2O2 en route to the formation of H2O. Kinetic isotope effect experiments confirm the participation of hydrogen transfer in the rate-determining step of both the reduction of O2 and H2O2. This work constitutes the first example of hydrogen atom transfer for small-molecule activation with reduced polyoxometalates, where both electron and proton originate from the cluster.
- Brennessel, William W.,Fertig, Alex A.,Matson, Ellen M.,McKone, James R.
-
p. 15756 - 15768
(2021/10/02)
-
- Determining Proton-Coupled Standard Potentials and X-H Bond Dissociation Free Energies in Nonaqueous Solvents Using Open-Circuit Potential Measurements
-
Proton-coupled electron transfer (PCET) reactions are increasingly being studied in nonaqueous conditions, where the thermochemistry of PCET substrates is largely unknown. Herein, we report a method to obtain electrochemical standard potentials and calculate the corresponding bond dissociation free energies (BDFEs) of stable PCET reagents in nonaqueous solvents, using open-circuit potential (OCP) measurements. With this method, we measure PCET thermochemistry in acetonitrile and tetrahydrofuran for substrates with O-H and N-H bonds that undergo 1e-/1H+ and 2e-/2H+ redox processes. We also report corrected thermochemical values for the 1/2H2(g)/H?1M and H+/H? (CG) couples in several organic solvents. For 2e-/2H+ couples, OCP measurements provide the multielectron/multiproton standard potential and the average of the two X-H BDFEs. In contrast to traditional approaches for calculating BDFEs from electrochemical measurements, the OCP method directly measures the overall PCET reaction thermodynamics and avoids the need for a pKa scale in the solvent of interest. Consequently, the OCP approach yields more accurate thermochemical values and should be general to any solvent mixture compatible with electrochemical measurements. The longer time scale of OCP measurements enables accurate thermochemical measurements for redox couples with irreversible or distorted electrochemical responses by cyclic voltammetry, provided the PCET reaction is chemically reversible. Recommendations for successful OCP measurements and limitations of the approach are discussed, including the current inability to measure processes involving C-H bonds. As a straightforward and robust technique to determine nonaqueous PCET thermochemistry, these OCP measurements will be broadly valuable, with applications ranging from fundamental reactivity studies to device development.
- Agarwal, Rishi G.,Mayer, James M.,Wise, Catherine F.
-
supporting information
p. 10681 - 10691
(2020/07/06)
-
- 1-Methyl-1,4-cyclohexadiene as a Traceless Reducing Agent for the Synthesis of Catechols and Hydroquinones
-
Pro-aromatic and volatile 1-methyl-1,4-cyclohexadiene (MeCHD) was used for the first time as a valid H-atom source in an innovative method to reduce ortho or para quinones to obtain the corresponding catechols and hydroquinones in good to excellent yields. Notably, the excess of MeCHD and the toluene formed as the oxidation product can be easily removed by evaporation. In some cases, trifluoroacetic acid as a catalyst was added to obtain the desired products. The reaction proceeds in air and under mild conditions, without metal catalysts and sulfur derivatives, resulting in an excellent and competitive method to reduce quinones. The mechanism is attributed to a radical reaction triggered by a hydrogen atom transfer from MeCHD to quinones, or, in the presence of trifluoroacetic acid, to a hydride transfer process.
- Baschieri, Andrea,Amorati, Riccardo,Valgimigli, Luca,Sambri, Letizia
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p. 13655 - 13664
(2019/10/28)
-
- Highly selective conversion of guaiacol to: Tert -butylphenols in supercritical ethanol over a H2WO4 catalyst
-
The conversion of guaiacol is examined at 300 °C in supercritical ethanol over a H2WO4 catalyst. Guaiacol is consumed completely, meanwhile, 16.7% aromatic ethers and 80.0% alkylphenols are obtained. Interestingly, tert-butylphenols are produced mainly with a high selectivity of 71.8%, and the overall selectivity of 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol is as high as 63.7%. The experimental results indicate that catechol and 2-ethoxyphenol are the intermediates. Meanwhile, the WO3 sites play an important role in the conversion of guaiacol and the Br?nsted acid sites on H2WO4 enhance the conversion and favour a high selectivity of the tert-butylphenols. The recycling tests show that the carbon deposition on the catalyst surface, the dehydration and partial reduction of the catalyst itself are responsible for the decay of the H2WO4 catalyst. Finally, the possible reaction pathways proposed involve the transetherification process and the alkylation process during guaiacol conversion.
- Mai, Fuhang,Cui, Kai,Wen, Zhe,Wu, Kai,Yan, Fei,Chen, Mengmeng,Chen, Hong,Li, Yongdan
-
p. 2764 - 2771
(2019/02/01)
-
- Reactivity of iPrPCPIrH4 with para-benzoquinones
-
In the interest of investigating new hydrogen acceptors for pincer–iridium catalyzed dehydrogenations with the ability to be catalytically recycled, a series of para-benzoquinones have been reacted with iPrPCPIrH4 in various solvents and conditions. Preliminary results indicate that a wide range of quinones are capable of dehydrogenating iPrPCPIrH4, and that several turn-overs in alcohol dehydrogenation by iPrPCPIr are possible at room temperature using benzoquinone acceptors. However, strong acceptor–catalyst interactions are inhibitory toward catalysis when the acceptor is used in excess. A new class of (bis)-η2 pi-adducts, formed between iPrPCPIr and benzoquinones, nicknamed “barber-chairs”, has been identified and 3 examples have been characterized.
- Wilklow-Marnell, Miles,Brennessel, William W.,Jones, William D.
-
p. 209 - 214
(2017/11/24)
-
- Liquid crystal orientation agent, crystal orientation film and liquid crystal display element
-
PROBLEM TO BE SOLVED: To provide a liquid crystal orientation agent to provide a liquid crystal display where a voltage retention rate is high, a residual DC is suppressed and long term light dependability is high, and besides, to provide a diamine which is a raw material for a polymer used for the liquid crystal orientation agent.SOLUTION: A diamine shown in a formula (I-2). Or a liquid crystal orientation agent containing polyamic acid provided by reacting a mixture of the diamine and another diamine with tetracarboxylic dianhydride, or a derivative of the polyamic acid.
- -
-
Paragraph 0123
(2016/12/16)
-
- {Cu2+-Co3+-Cu2+} and {Cu2+-Fe3+-Cu2+} heterobimetallic complexes and their catalytic properties
-
We report on the heterobimetallic complexes {Cu+-Co3+-Cu+} (3), {Cu+-Fe3+-Cu+} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) and show their catalytic applications in the oxidation of hindered phenols and the oxidative coupling of terminal alkynes. The former reaction produces C-C-coupled and dealkylated products, whereas the latter leads to the homo- and heterocoupling of terminal alkynes. The facile redox interconversion between Cu+ and Cu2+ for the secondary metal ions in these heterobimetallic complexes appears to be essential for the observed catalysis, and an important design aspect is better substrate accessibility and the use of molecular oxygen as the sole oxidant. Heterobimetallic complexes {Cu+-Co3+-Cu+} (3), {Cu+-Fe3+-Cu+} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) have been used as catalysts for the oxidation of substituted phenols and the oxidative homo- and heterocoupling of terminal alkynes.
- Srivastava, Sumit,Ali, Afsar,Tyagi, Adish,Gupta, Rajeev
-
p. 2113 - 2123
(2015/04/27)
-
- {Cu2+-Co3+-Cu2+} and {Cu 2+-Fe3+-Cu2+} heterobimetallic complexes and their catalytic properties
-
We report on the heterobimetallic complexes {Cu+-Co 3+-Cu+} (3), {Cu+-Fe3+-Cu +} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) and show their catalytic applications in the oxidation of hindered phenols and the oxidative coupling of terminal alkynes. The former reaction produces C-C-coupled and dealkylated products, whereas the latter leads to the homo- and heterocoupling of terminal alkynes. The facile redox interconversion between Cu+ and Cu 2+ for the secondary metal ions in these heterobimetallic complexes appears to be essential for the observed catalysis, and an important design aspect is better substrate accessibility and the use of molecular oxygen as the sole oxidant. Heterobimetallic complexes {Cu+-Co3+-Cu +} (3), {Cu+-Fe3+-Cu+} (4), {Cu 2+-Co3+-Cu2+} (5), and {Cu2+-Fe 3+-Cu2+} (6) have been used as catalysts for the oxidation of substituted phenols and the oxidative homo- and heterocoupling of terminal alkynes. Copyright
- Srivastava, Sumit,Ali, Afsar,Tyagi, Adish,Gupta, Rajeev
-
p. 2113 - 2123
(2014/05/06)
-
- Sulfonic acid functionalized MCM-41 as solid acid catalyst for tert-butylation of hydroquinone enhanced by microwave heating
-
Covalently linked sulfonic acid (SO3H) modified MCM-41 mesoporous catalysts was prepared, characterized and its catalytic activity under microwave irradiation was evaluated. The NH2-MCM-41 was first prepared by anchoring (3-aminoprop
- Ng, Eng-Poh,Mohd Subari, Siti Norbayu,Marie, Olivier,Mukti, Rino R.,Juan, Joon-Ching
-
-
- An efficient reduction of quinones by formate-palladium/carbon system
-
Ammonium formate in presence of palladium-carbon is an efficient system for catalytic transfer hydrogenation of several functional groups under mild conditions. However, this system was not found effective for reduction of quinones to hydroquinones, although reduction could be effected with phosphinic acid, phosphinates or cyclohexene as donors. A reexamination of this reaction suggested that formates were good hydrogen donors in this reduction but the reaction was inhibited due to quinhydrone formation. A simple expedient of maintaining low concentration of quinone during catalytic transfer hydrogenation reduction gave excellent yields of the hydroquinone. Compared to formates, formic acid was found to be a poor hydrogen donor.
- Pande, Poorn Prakash
-
experimental part
p. 2549 - 2553
(2010/11/05)
-
- PROCESS FOR CONVERSION OF PHENOL TO HYDROQUINONE AND QUINONES
-
The present invention relates to a process for the conversion of phenol to hydroquinone and quinones. More particularly this invention relates to a process for the oxidation of phenol to a mixture of 1,4-benzoquinone and hydroquinone using an oxidant in the presence of titanium superoxide as a reusable catalyst in a liquid phase condition.
- -
-
Page/Page column 7; Table 1
(2008/06/13)
-
- 4-Formyl amino-n-methylpiperidine derivatives, the use thereof as stabilisers and organic material stabilised therewith
-
The present invention relates to 4-formylamino-N-methylpiperidine derivatives of the formula (I) where the variables are as defined in the Description, to a process for preparing these piperidine derivatives, to the use of these piperidine derivatives of the invention, or prepared according to the invention, for stabilizing organic material, in particular for stabilizing plastics or coating materials, and also to the use of these piperidine derivatives of the invention, or prepared according to the invention, as light stabilizers or stabilizers for wood surfaces. The present invention further relates to stabilized organic material which comprises these piperidine derivatives of the invention or prepared according to the invention.
- -
-
-
- Process for preparation of a benzofuran derivative
-
An industrially useful process for producing benzofuran derivatives of formula (1) by formylating a compound of formula (2) (where A1 is a protective group), followed by reaction with a compound of formula (4) (where X1 is a halogen atom), then performing a cyclizing reaction and subsequently performing a reaction for hydroxyl group deprotection.
- -
-
Page/Page column 14
(2010/01/31)
-
- Hydrogen-bonding effects on the properties of phenoxyl radicals. An EPR, kinetic, and computational study
-
The effect of 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) on the properties of phenoxyl radicals has been investigated. HFP produces large variations of the phenoxyl hyperfine splitting constants indicative of a large redistribution of electron spin density, which can be accounted for by the increased importance of the mesomeric structures with electric charge separation. The conformational rigidity of phenoxyl radicals with electron-releasing substituents is also greatly enhanced in the presence of HFP, as demonstrated by the 2 kcal/mol increase in the activation energy for the internal rotation of the p-OMe group in the p-methoxyphenoxyl radical. By using the EPR equilibration technique, we have found that in phenols the O-H bond dissociation enthalpy (BDE) is lowered in the presence of HFP because it preferentially stabilizes the phenoxyl radical. In phenols containing groups such as OR that are acceptors of H-bonds, the interaction between HFP and the substituent is stronger in the phenol than in the corresponding phenoxyl radical because the radical oxygen behaves as an electron-withdrawing group, which decreases the complexating ability of the substituent. In phenols containing OH or NH2 groups, EPR experiments performed in H-bond accepting solvents showed that the interaction between the solvent and the substituent is much stronger in the phenoxyl radical than in the parent phenol because of the electron-withdrawing effect of the radical oxygen, which makes more acidic, and therefore more available to give H-bonds, the OH or NH2 groups. These experimental results have been confirmed by DFT calculations. The effect of HFP solvent on the reactivity of phenols toward alkyl radicals has also been investigated. The results indicated that the decrease of BDE observed in the presence of HFP is not accompanied by a larger reactivity. The origin of this unexpected behavior has been shown by DFT computations. Finally, a remarkable increase in the persistency of the α-tocopheroxyl radical has been observed in the presence of HFP.
- Lucarini, Marco,Mugnaini, Veronica,Pedulli, Gian Franco,Guerra, Maurizio
-
p. 8318 - 8329
(2007/10/03)
-
- QSAR for the cytotoxicity of 2-alkyl or 2,6-dialkyl, 4-X-phenols: The nature of the radical reaction
-
In a continuation of studies on the radical mediated toxicity of phenols to leukemia cells, a set of di- and tri-substituted phenols with mostly alkyl substituents in the ortho position were examined. These analogs are similar in structure to the commercial antioxidants BHA and BHT. A QSAR analysis of their growth inhibitory constants led to the formulation of this simple but unusual equation based on 18 congeners: log 1/C = -0.47Es-2 + 2.42RR + 2.43; r3 = 0.934 ES-2 is the Taft steric parameter for the larger of the two ortho substituents while ER is Otsu's radical parameter, which was originally defined to correlate radical reactions.
- Selassie, Cynthia D.,Verma, Rajeshwar P.,Kapur, Sanjay,Shusterman, Alan J.,Hansch, Corwin
-
p. 1112 - 1117
(2007/10/03)
-
- Chemistry of L-ascorbic acid. Part 3.1 Photoreduction of quinones with 5,6-O-isopropylidene-L-ascorbic acid
-
Upon irradiation with UV light, instead of undergoing the Paterno-Buechi reaction, 5,6-O-isopropyIidene-L-ascorbic acid reduced quinones quite efficiently and rapidly to the corresponding hydroquinones. The Royal Society of Chemistry 2000.
- Kulkarni, Mukund G.,Kate, Sandesh D.
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p. 4242 - 4244
(2007/10/03)
-
- Dienone tautomers of 4-alkoxy-2,6-di-terf-butylphenols
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Generation and isolation of 4-alkoxycyclohexa-2,5-dienones 9, the tautomeric forms of the title phenols (10), is described. They are generated efficiently by the Ag ion mediated reaction of 4-bromocyclohexa-2,5-dienone 3b with simple alcohols, although they can be irreversibly isomerized into 10 under the reaction conditions. Crude materials with high amounts of 9 can be obtained by conducting the reaction with AgClO4 in the presence of Na2CO3 or with AgOCOCF3 and by interrupting the reaction shortly after the formation of 9 is complete. The AgOCOCF3 reaction produces labile 4-(trifluoroacetoxy)cyclohexa-2,5-dienone 11 also, the formation of which becomes significant as the alcohol becomes bulky. All of 9 prove to be very much susceptible to the prototropic rearrangement into 10 by catalysis with base, acid, or SiO2. Crude dienones 9 can be conveniently prepared directly from phenol 6 by treatment for a short time with Br2 in alcohols containing AgClO4 and Na2CO3. A one-pot synthesis from 6 of 4-oxyfunctionalized 2,6-di-tert-butylphenols, including 10, is also described.
- Omura, Kanji
-
p. 7156 - 7161
(2007/10/03)
-
- Antioxidant and cholesterol lowering properties of 2,6-di-t-butyl-4- [(dimethylphenylsilyl)methyloxy]phenol and derivatives: A new class of anti- atherogenic compounds
-
Di-t-butylphenol derivatives were synthesized and evaluated as antioxidants and cholesterol lowering agents. When evaluated in cholesterol- fed rabbits, the compounds were found to exhibit both properties. Of special interest was the finding that several of the compounds elevated HDL cholesterol levels.
- Parker, Roger A.,Barnhart, Roger L.,Chen, Kim S.,Edwards, Michael L.,Matt Jr., James E.,Rhinehart, Barry L.,Robinson, Keith M.,Vaal, Mark J.,Yates, Mark T.
-
p. 1559 - 1562
(2007/10/03)
-
- The Reactions of 2,6-Di-tert-butyl-1,4-benzoquinone with Triphenylphosphine, -arsine, and stibine and their Oxides
-
The action of triphenylphosphine (1a), triphenylarsine (1b), triphenylstibine (1c) and their oxides 6a-c on 2,6-di-tert-butyl-1,4-benzoquinone (5) has been investigated.The constitution of the resulting adduct has been elucidated by degradative experiments and spectral data.It was shown that: 1) Both carbon attack and oxygen attack were observed in the reaction of 1a and 5 to give C-phosphoniumquinol betaine 10, hydroquinone 8 and triphenylphosphine oxide (6a).TPAs, in contrast to TPP, attacks the carbonyl-oxygen.The final product was the betaine 16 which was converted by aqueous methanol to the complex 17.Conversely, in the reaction of 5 with 1c, deoxygenation was attained to afford the stiboranylidene structure 18.The activity of TPX=O (6a-c) toward 5 was also tested.
- Abdou, Wafas M.,El-Khoshnieh, Yehia O.,Kamel, Azza A.
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p. 1841 - 1850
(2007/10/03)
-
- Phosphorylation of 2,6-di-tert-butylphenol and its derivatives
-
2-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,2λ5-dioxaphospholane 2-oxide was obtained by reaction of 2-chloro-1,3,2λ5-dioxaphospholane 2-oxide with 2,6-di-tert-butylhydroquinone, while its 2,6-di-tert-butyl-p-benzoquinone is reduced with 1,3,2λ5-dioxaphospholane 2-oxide yielding 2,6-di-tert-butylhydroquinone.Unlike 2-chloro-1,3,2λ5-dioxaphospholane 2-oxide, 2-chloro-1,3,2-dioxaphospholane reacts with the sterically shielded hydroxy group of 2,6-di-tert-butylphenol.
- Munik, S. N.,Eliseenkov, V. N.,Ivanov, B. E.
-
p. 346 - 350
(2007/10/03)
-
- SYNTHESIS OF 2,6-DI-tert-BUTYL-4-(3,5-DI-tert-BUTYL-4-HYDROXYBENZYLIDENE)-2,5-CYCLOHEXADIENONE
-
2,6-Di-tert-butyl-4-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2,5-cyclohexadienone has been prepared in 63-92percent yield by oxidative dehydrogenation of 4,4'-methylenebis(2,6-di-tert-butylphenol) with various quinones.The products of quinone reduction have been isolated.
- Mukmeneva, N. A.,Bukharov, S. V.,Kadyrova, V. Kh.,Zharkova, V. M.
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p. 1350 - 1351
(2007/10/02)
-
- Process for the preparation of quinones
-
Phenols are oxidated to quinones with hydrogen peroxide in the presence of catalytic amounts of bromine, iodine, hydrogen bromide and hydrogen iodide.
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-
- Oxidation of catechol and of 2,6-di-tert butylphenol by dioxiranes
-
In a biomimetic transformation, the selective oxidation of catechol (2) to Z,Z-muconic acid (3) has been achieved under extremely mild conditions using methyl(trifluoromethyl)dioxirane (1b). Both dioxirane 1b and dimethyldioxirane (1a) have been applied to the oxidation of 2,6-di-tert-butylphenol (4); the product natures suggest the incursion of radical pathways.
- Altamura,Fusco,D'Accolti,Mello,Prencipe,Curci
-
p. 5445 - 5448
(2007/10/02)
-
- Process for the preparation of quinones
-
Phenols are oxidated to quinones with hydrogen peroxide in the presence of catalytic amounts of bromine, iodine, hydrogen bromide and hydrogen iodide.
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-
- Electrochemical Oxidation, VII. Synthesis and Structure of 7-tert-Butyl-2-methylbenzoxazoles
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Anodic oxidation of 15 tert-butylphenols 1a - o in absolute acetonitrile or acetonitrile/perchloric acid leads to the corresponding 7-tert-butyl-2-methylbenzoxazoles 3a - o.The proof of the structure was achieved by independent synthesis of 3k, and by 13C NMR spectroscopy as well as by X-ray analysis of 7-tert-butyl-2-methyl-5-benzoxazolecarbaldehyde (3j).The influence of the supporting electrolyte on the formation of the oxidation products is discussed.
- Dreher, Eberhard-Ludwig,Bracht, Juergen,El-Mobayed, Medhat,Huetter, Peter,Winter, Werner,Rieker, Anton
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p. 288 - 308
(2007/10/02)
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- Formation of Diphenyl Ethers from Cyclohexa-2,5-dienones via 4-phenoxy-4-(1-alkoxy)cyclohexa-2,5-dienones as Probable Intermediates
-
Acid-catalysed reactions of the cyclohexa-2,5-dienones (3) and (14) with phenol afford diphenyl ethers.Quinol ethers are considered to be intermediates in these reactions, with aromatisation of the cyclohexa-2,5-dienone ring by loss of the 4-(1-alkoxy) side-chain as an aldehyde constituting the driving force.
- Karhu, Matti
-
p. 303 - 306
(2007/10/02)
-
- REXTION OF SUPEROXO Co(III) COMPLEX WITH QUINONES FORMATION OF A SEMIQUINONE Co(III) COMPLEX
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The superoxo complex (3-) was found to act as a reducing agent towards quinones.One-electron reduction took place with o-quinone whereas two-electrons reduction with p-quinones. 3,5-Di-t-butyl-o-benzoquinone gave the corresponding semiquinone Co(III) complex quantitatively.
- Nishinaga, A.,Tomita, H.,Matsuura, T.
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p. 4853 - 4854
(2007/10/02)
-
- SYNTHESIS OF 4-ALKOXY- AND 4-ACYLOXY-2,6-DI-tert-BUTYLPHENOLS AND QUINOL ETHERS BASED ON THEM
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4-Alkoxy- and 4-acyloxy-2,6-di-tert-butylphenols were obtained by the alkylation and acylation of 2,6-di-tert-butyl-p-dihydroxybenzene.With quinone dioximes under oxidizing conditions the products form quinol ethers.
- Dobronravova, Z. A.,Meshcheryakov, V. I.,Prishchenko, Yu. E.,Gavrilov, L. D.,Vereshchagin, L. I.
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p. 910 - 914
(2007/10/02)
-
- Reactions of 4-Bromo-4-(1-hydroxypropyl)-2,6-di-t-butylcyclohexa-2,5-dienone in Methanolic Sulphuric Acid
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Reactions of the title compound (1) in methanolic sulphuric acid are described.At high acid concentrations the main reaction is the cleavage of the side chain as propionic aldehyde.At low acid concentrations the products are mainly formed by hydrolysis of (1) and subsequent reduction and oxidation reactions involving the bromide ion and bromine.
- Karhu, Matti
-
p. 1595 - 1598
(2007/10/02)
-
- Piperidine derivatives
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New 1- and 4-substituted piperidines are stabilizers for organic material. They are produced by reacting corresponding 1-substituted piperidinols with acid chlorides or corresponding 4-substituted piperidines with a compound introducing into the 1-position a residue.
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- Piperidine derivatives
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New piperidine derivatives of 1,3-pyrimidine and 1,3,5-triazine are used as stabilizers for organic materials, especially for polymers.
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- Hydroxyaryl-tetramethyl-piperidines
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New 4-(4'-hydroxyaryl)-2,2,6,6-tetramethyl-piperidines are used as stabilisers for organic materials, especially for polymers.
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-
- Substituted piperidin-4-ols
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Disclosed are stabilized compositions comprising a polymer, especially polyolefines, and a minor proportion of a 1,2,2,6,6-pentasubstituted piperidin-4-ol. The new compositions possess good light stability.
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- Substituted piperazines and polymeric compositions stabilized thereby
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Substituted piperazines are stabilizers for synthetic polymeric materials normally subject to deterioration caused by ultraviolet light. The compounds are prepared by the alkylation reaction between a substituted piperazine dione and an organic halide followed by reduction with lithium aluminum hydride. Polymeric compsitions containing these stabilizers may also contain a hindered phenolic compound. A typical embodiment is 15,15'-dodecamethylene-bis(7,15-diazadispiro[5,1,5,3]hexadecane).
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- Substituted piperazine diones and polymeric compositions stabilized thereby
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Substituted piperazine diones are stabilizers for synthetic polymeric materials normally subject to deterioration caused by ultraviolet light. The compounds are prepared by the alkylation reaction between a substituted piperazine dione and an organic halide. Polymeric compositions containing these stabilizers may also contain a hindered phenolic compound. A typical embodiment is 15,15'-dodecamethylenebis(7,15-diazadispiro[5,1,5,3]hexadecane-14,16-dione).
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- Piperidine derivatives
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A composition comprising an organic material and, as stabiliser, a compound having the formula SPC1 And salts thereof, wherein R1 and R2 are the same or different and each is an alkyl residue having from 1 to 12 carbon atoms or R1 and R2, together with the carbon atom to which they are bound, form a cycloalkyl residue having from 5 to 12 carbon atoms in the ring, Y is O, hydrogen, a straight or branched alkyl residue having from 1 to 20 carbon atoms, an alkenyl or alkynyl residue having from 3 to 12 carbon atoms, an aralkyl residue having from 7 to 12 carbon atoms or a group having the formula EQU1 wherein R is hydrogen, or a methyl or phenyl residue and R3 is hydrogen or a straight- or branched chain alkyl residue having from 1 to 12 carbon atoms.
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- 4-Piperidine acetamides
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New piperidine derivatives and in particular esters and amides of substituted (piperidinyl-4) acetic acid are used as stabilisers for polymers, especially for polyolefines.
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- 4-(4'-Hydroxycyclohexyl)-2,2,6,6-tetramethyl piperidines
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A compound having the formula:- SPC1 And salts thereof, wherein R1, R2, R3 and R4 are the same or different and each is hydrogen, an alkyl residue having from 1 to 9 carbon atoms, a cycloalkyl residue having from 5 to 14 carbon atoms or a cycloalkyl-alkyl residue having from 7 to 14 carbon atoms, Y is hydrogen, 0°, an alkyl residue having from 1 to 4 carbon atoms, or an aralkyl residue having from 7 to 12 carbon atoms and Z is hydrogen, an unsubstituted or substituted alkyl residue having from 1 to 20 carbon atoms, an alkenyl or alkynyl residue having from 2 to 20 carbon atoms, a cycloalkyl residue having from 5 to 12 carbon atoms, an aralkyl residue having from 7 to 12 carbon atoms, an aryl residue having from 6 to 12 carbon atoms, or the group having the formula: wherein Z1 has the same significance as Z as hereinbefore defined, or Z1 is a group --NR5 R6 wherein R5 is hydrogen or an alkyl residue having from 1 to 4 carbon atoms and R6 is hydrogen, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 5 to 12 carbon atoms, an aralkyl residue having from 7 to 12 carbon atoms or an aryl residue having from 6 to 12 carbon atoms having light stabilising activity.
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- N-carbamoyl imidazolidinones and imidazolidinethiones
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Compounds having the formula SPC1 As well as salts thereof, wherein n is 1 or 2, Y is 0, hydrogen or a straight- or branched chain alkyl residue having from 1 to 4 carbon atoms Z is 0 or S and when n is 1, R1 is a substituted or unsubstituted hydrocarbyl residue having from 1 to 20 carbon atoms and when n is 2, R1 is a substituted or unsubstituted hydrocarbyl residue having from 2 to 20 carbon atoms, are suitable as stabilisers of organic material.
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- 1,4-Diazaepine-5-ones
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According to the present invention, there are provided compounds having the formula: SPC1 And salts thereof, wherein n is 1 or 2, X is O of NH, Y is O, hydrogen or a branched- or straight chain alkyl residue having from 1 to 4 carbons and R1 is a hydrocarbyl residue having from 1 to 20 carbon atoms, which are useful as stabilisers for polymers.
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- Piperidine derivatives
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New piperidine derivatives and in particular esters and amides of substituted (piperidinylidene-4) acetic acid are used as stabilizers for polymers, especially for polyolefines.
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- 3,5-Dialkyl-4-hydroxyphenylalkyl substituted piperazine diones and polymeric compositions stabilized thereby
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3,5-dialkyl-4-hydroxyphenylalkyl substituted piperazine diones are stabilizers for synthetic polymeric materials normally subject to deterioration caused by ultraviolet light. The compounds are prepared by the alkylation reaction between a substituted piperazine dione and 3,5-dialkyl-4-hydroxyphenylalkyl halide. Polymeric compositions containing these stabilizers may also contain a hindered phenolic compound. A typical embodiment is 15-(3',5'-di-t-butyl-4'-hydroxybenzyl)(7,15-diazadispiro[5,1,5,3]hexadecane-14,16-dione).
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- Esters of piperidinols
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New alkyl substituted p-hydroxy aryl esters and alkyl substituted p-hydroxy aralkyl esters of 2,2,6,6-tetrasubstituted piperidin-4-ols are used as stabilizers for organic materials, especially for polymers.
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- 4-(Carboxamidoethyl) piperidines
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New piperidine derivatives and in particular 2-(piperidinyl-4')-ethyl-amines, -ethers and -esters are used as stabilisers for polymers, especially for polyolefines.
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- Substituted piperazine dione oxyls and hydroxides and polymer compositions stabilized thereby
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Substituted piperazine dione oxyls and hydroxides are stabilizers for synthetic polymeric materials normally subject to deterioration caused by ultraviolet light. The compounds may be prepared by first preparing a substituted piperazine dione with subsequent oxidation of the piperazine dione to yield the oxyl and reduction of the oxyl to yield the hydroxide derivative. Polymeric compositions containing these stabilizers may also contain a hindered phenolic compound. A typical embodiment is 15-n-octadecyl-7-oxyl-7,15-diazadispiro[5,1,5,3]hexadecane-14,16-dione.
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