1879-09-0Relevant articles and documents
Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
supporting information, (2020/05/18)
The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
Chemical Kinetics of the Alkylation of Xylenol for the Separation of Their Close-Boiling Isomers from Coal Tar
Cong-Yu, Ke,Lu, Guo-Min,Sun, Wu-Juan,Tang, Xuan,Wei, Ying-Lin,Zhang, Qun-Zheng,Zhang, Xiao-Xia,Zhang, Xun-Li
, p. 1291 - 1299 (2020/12/02)
Abstract: To support the industrial design and process development for the separation of xylenol isomers from coal tar, the present work was focused on 2,4/2,5-xylenol mixture as 2,4-xylenol and 2,5-xylenol have very close boiling points. Specifically, th
Highly selective conversion of guaiacol to: Tert -butylphenols in supercritical ethanol over a H2WO4 catalyst
Mai, Fuhang,Cui, Kai,Wen, Zhe,Wu, Kai,Yan, Fei,Chen, Mengmeng,Chen, Hong,Li, Yongdan
, p. 2764 - 2771 (2019/02/01)
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.
Phenol o-position alkylation method
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Paragraph 0045; 0046; 0047; 0048, (2017/08/27)
The invention provides a phenol o-position alkylation method which comprises the following step: in the presence of a catalyst, a phenol substance and an alkylating agent react, wherein the catalyst is an aryl zinc salt generated from a reaction of zinc and a phenol compound; the alkylating agent is olefin; the phenol substance comprises polyphenol such as catechol and hydroquinone, and further comprises one to two alkyl groups, or halide based phenols; the alkyl group is straight-chain or branched paraffin with 1-10 carbons. By adopting the phenol o-position alkylation method, the preparation efficiency is greatly improved, and the conversion rate can be further increased. The invention further provides a method for preparing 2,6-di-tert-butyl-4-methylphenol, and a reaction kettle for preparation.
About selective methods of synthesis of 6-tert-butyl-2-methylphenol and 6-tert-butyl-2,4-dimethylphenol
Krysin,Khlebnikova,Khlebnikov,Pokrovskii,Vasil'ev
, p. 1156 - 1162 (2011/05/04)
Vapor phase catalytic methylation with methanol of 2-tert-butylphenol at the temperature 280-300°C proceeds selectively with formation of 6-tert-butyl-2-methylphenol. Elevating reaction temperature above 300°C leads to formation of 2,6-dimethylphenol. Reaction of 2-tert-butylphenol with methanol in alkaline medium in the presence of zinc oxide is shown to lead initially to formation of a mixture of calixarenes and methylenebisphenols that at elevated temperature exert splitting leading in future to 6-tert-butyl-2,4-dimethylphenol. Obtaining it in this reaction from 2,2′-methylenebis-(6-tert-butyl-4-methylphenol) proceeds selectively. Pathways of the reductive methylation of methylenebisphenols with methanol in alkaline medium is considered.
4-Formyl amino-n-methylpiperidine derivatives, the use thereof as stabilisers and organic material stabilised therewith
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, (2008/06/13)
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.
Thioether substituted hydroxybenzophenones and stabilized compositions
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, (2008/06/13)
2-Hydroxybenzophenone derivatives substituted in the 4′-position by a thioether moiety exhibit enhanced absorption in the UV at longer wavelength. Compositions comprising organic material subject to actinic degradation are beneficially stabilized with such derivatives.
Color-stabilized basic monomers, process for producing the same and method for handling the same
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, (2008/06/13)
Color-stabilized basic monomers are provided. Said basic monomers are obtained by adding, to a basic monomer ?e.g. an N,N-dialkylaminoalkyl (meth)acrylate or an N,N-dialkylaminoalkyl (meth)acrylamide!, at least one member selected from the group consisting of amido group-containing compounds, phosphorous acid esters, phosphoric acid esters and phosphines and at least one phenol compound represented by the general formula: STR1 wherein R5, R6, R8 and R9 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and R7 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The color-stabilized basic monomers are more resistant to coloration when they are handled under such conditions that the oxygen concentration in the gas phase contacting therewith is 0.01 to 10% by volume.
Lubricant composition
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, (2008/06/13)
A composition comprising a) a lubricant or a hydraulic fluid and b) at least one compound of the general formula I STR1 in which x=1 or 2 and, if x=1, R is as defined for R1 or R3 --O-- or, if x=2, R is as defined for R8, and R1 and R3 are, for example, alkyl, cycloalkyl, alkenyl, phenyl, naphthyl, aralkyl or alkaryl, or alkyl, cycloalkyl, alkenyl, phenyl, naphthyl, aralkyl or alkaryl, which are monosubstituted or polysubstituted by groups from the series comprising halogen, cyano, nitro, e.g. --OCH3 or e.g. --COOCH3, or alkyl, cycloalkyl, alkenyl, aralkyl or alkaryl which are interrupted by one or more groups from the series comprising --O--, --S--, --NH--, STR2 or alkyl, cycloalkyl, alkenyl, aralkyl or alkaryl which are monosubstituted or polysubstituted by groups from the series comprising halogen, cyano, nitro, e.g. --OCH3 or e.g. --COOCH3 and interrupted by one or more groups from the series comprising --O--, --S--, --NH--, STR3 and R2 is NR4 R5, --OR6 or --SR7, and R4 and R5 are identical or different and are, for example, --H, alkyl, phenyl, naphthyl, aralkyl or alkaryl, or R4 and R5, together with the N atom linking them, form, for example, a piperidine or morpholine radical, and R6 and R7 can be alkyl which may be interrupted by one or more groups from the series comprising --O--, --S--, --NH--, STR4 or are, for example, phenyl, naphthyl, alkaryl or aralkyl, and R8 can be alkylene which may be interrupted by at least one --O-- group or alkylidene which may be interrupted by at least one --O-- group. Some of the compounds of the formula I are novel. The compositions show an improved stability towards oxidative degradation, confer protection under extreme pressures and reduce frictional wear.
Substituted 1,4-diamino-2-butene stabilizers
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, (2008/06/13)
N,N,N',N'-Tetrasubstituted 1,4-diamino-2-butenes where the substituents are alkyl, cycloalkyl, aralkyl, aryl or mixtures thereof provide effective antioxidant protection to lubricants and/or synthetic polymers.
