25134-01-4

Usage

Uses

Used in Fuel Cells:
PPO, when modified with imidazolium and combined with liquid ionic graphene oxide, is used as an anion exchange membrane (AEM) composite. This composite has a peak power density of 136 mW cm?2, making it suitable for the fabrication of high-performance fuel cells.
Used in Vanadium Redox Flow Batteries (VRFBs):
PPO can be sulfonated to form a long-chained polymeric structure with an efficiency of 81.8% at a current density of 120 mA cm?2. This structure is potentially useful in vanadium redox flow batteries (VRFBs) as an effective energy storage system.
Used in Microbial Desalination Cell Systems (MDCS):
PPO can also be utilized in the formation of anion exchange membranes (AEMs), which are employed in the development of microbial desalination cell systems (MDCS) for water treatment applications.
Used in Telecommunication and Business Equipment:
Commercially, PPO is often blended with polystyrene, primarily in the form of high-impact polystyrene, to facilitate melt-processing and lower costs while maintaining the desirable properties of the pure polymer. Polystyrene-modified poly(2,6-dimethyl-1,4-phenylene oxide), commonly referred to as PPO, is used in the manufacturing of telecommunication and business equipment housings and components.
Used in Automotive Industry:
The blend of PPO and polystyrene also finds applications in the automotive industry for the production of various automotive parts, benefiting from the combined properties of both materials.

Preparation

Oxidative coupling is readily accomplished by passing oxygen into a reaction mixture containing 2,6-xylenol, pyridine and cuprous chloride. (The molar ratio of pyridine to cuprous ion is generally in the range 10: 1 to 100: 1.) External heating is unnecessary; during the course of the reaction the temperature rises to about 70°C. The polymer is precipitated with dilute hydrochloric acid and collected by filtration. It is generally accepted that aryloxy radicals are intermediates in the polymerization reaction since ESR studies have shown the presence of both monomeric and polymeric aryloxy radicals in polymerizing solutions of 2,6- xylenol. The simplest mechanism that can be suggested for the reaction is aromatic substitution:

Upstream product

• 2816-57-1 2,6-dimethylcyclohexanone 
• 824-42-0 2-methoxy-3-methylbenzaldehyde 
• 111-87-5 octanol 
• 19578-74-6 1,3-Dimethyl-2-(phenylmethoxy)benzene 
• 82054-07-7 3,3,3'',3''-tetramethyl-3a',4',7',7a'-tetrahydro-dispiro[oxirane-2,1'-(4,7-methano-inden)-8',2''-oxirane] 
• 4919-37-3 3,5-dimethyl-4-hydroxybenzoic acid 
• 87-62-7 2,6-dimethylaniline 
• 67-56-1 methanol 
• 108-95-2 phenol 
• 95-87-4 2,5-Dimethylphenol 
• 127-18-4 1,1,2,2-tetrachloroethylene 
• 40790-56-5 2,6-dimethyl-2-cyclohexen-1-one 
• 95-47-6 o-xylene 
• 1004-66-6 2-methoxy-1,3-dimethylbenzene 

Downstream Products

• 29237-05-6 4-(4,4'-dihydroxy-3,5,3',5'-tetramethyl-benzhydrylidene)-2,6-dimethyl-cyclohexa-2,5-dienone 
• 60211-21-4 4,2',6'-trimethyl-2,4'-methanediyl-di-phenol 
• 854669-64-0 3-chloro-1,1-bis-(4-hydroxy-3,5-dimethyl-phenyl)-butane 
• 108975-44-6 4-{[N-(2-hydroxy-ethyl)-anilino]-methyl}-2,6-dimethyl-phenol 
• 108170-13-4 2-(2,6-dimethyl-phenoxymethyl)-5-methoxy-pyran-4-one 
• 2786-80-3 4-hydroxy-3,5-dimethoxyazobenzene 
• 1778-65-0 2,6-Dimethyl-4-(4-nitro-phenylazo)-phenol 
• 43109-10-0 2,6-dimethyl-4-[(E)-(2,4-dinitrophenyl)diazenyl]phenol 
• 116130-99-5 (3-bromo-phenyl)-bis-(4-hydroxy-3,5-dimethyl-phenyl)-methane 
• 73324-22-8 1,1,1-trichloro-2,2-bis-(4-hydroxy-3,5-dimethyl-phenyl)-ethane 
• 107055-25-4 4-sec-Butyl-2,6-dimethyl-phenol 
• 102590-03-4 6,6-bis-(4-hydroxy-3,5-dimethyl-phenyl)-heptanoic acid 
• 115034-73-6 butyl-malonic acid bis-(2,6-dimethyl-phenyl ester) 
• 66232-87-9 GRI 406402 

Relevant academic research and scientific papers

Vapor phase methylation of phenol on Fe-substituted ZrO2 catalyst

Fe-doped ZrO2 compounds were prepared by a co-precipitation method. The compounds were characterized by X-ray diffraction, N2 adsorption-desorption, ultraviolet diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy–energy-dispersive X-ray spectroscopy, transmission electron microscopy, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy, and in situ Fourier transform infrared spectroscopy. The incorporation of Fe into ZrO2 lattice favored and effectively stabilized the formation of purely ZrO2 tetragonal phase. Subsequently, the catalytic activity of the Fe-doped ZrO2 compounds was evaluated toward vapor phase methylation of phenol. The catalytic activity was governed by Fe content and related to the Lewis acidity of the prepared catalyst.

Catalytic Synthesis of 2,6-Dimethylphenol from Methanol and Cyclohexanone over Titanium Oxide-supported Vanadium Oxide Catalysts

2,6-Dimethylphenol has been selectively synthesised from methanol and cyclohexanone in one step over a vanadia/TiO2 catalyst.

Catalytic Activation of Unstrained C(Aryl)-C(Alkyl) Bonds in 2,2′-Methylenediphenols

Catalytic activation of unstrained and nonpolar C-C bonds remains a largely unmet challenge. Here, we describe our detailed efforts in developing a rhodium-catalyzed hydrogenolysis of unstrained C(aryl)-C(alkyl) bonds in 2,2′-methylenediphenols aided by removable directing groups. Good yields of the monophenol products are obtained with tolerating a wide range of functional groups. In addition, the reaction is scalable, and the catalyst loading can be reduced to as low as 0.5 mol %. Moreover, this method proves to be effective to cleave C(aryl)-C(alkyl) linkages in both models of phenolic resins and commercial novolacs resins. Finally, detailed experimental and computational mechanistic studies show that with C-H activation being a competitive but reversible off-cycle reaction, this transformation goes through a directed C(aryl)-C(alkyl) oxidative addition pathway.

Impact of oxygen vacancies in Ni supported mixed oxide catalysts on anisole hydrodeoxygenation

The hydrodeoxygenation (HDO) activity of anisole has been investigated over Ni catalysts on mixed metal oxide supports containing Nb–Zr and Ti–Zr in 1:1 and 1:4 ratios. XRD patterns indicate the incorporation of Ti (or Nb) into the ZrO2 framewo

A mild and practical method for deprotection of aryl methyl/benzyl/allyl ethers with HPPh2andtBuOK

A general method for the demethylation, debenzylation, and deallylation of aryl ethers using HPPh2andtBuOK is reported. The reaction features mild and metal-free reaction conditions, broad substrate scope, good functional group compatibility, and high chemical selectivity towards aryl ethers over aliphatic structures. Notably, this approach is competent to selectively deprotect the allyl or benzyl group, making it a general and practical method in organic synthesis.

Reaction of hydroxyl radical with arenes in solution—On the importance of benzylic hydrogen abstraction

The regioselectivity of hydroxyl radical reactions with alkylarenes was investigated using a nuclear magnetic resonance (NMR)-based methodology capable of trapping and quantifying addition and hydrogen abstraction products of the initial elementary step of the oxidation process. Abstraction products are relatively minor components of the product mixtures (15–30 mol%), depending on the magnitude of the overall rate coefficient and the number of available hydrogens. The relative reactivity of addition at a given position on the ring depends on its relation to the methyl substituents on the hydrocarbons under study. The reactivity enhancements for disubstituted and trisubstituted rings are approximately additive under the conditions of this study.

Photocatalytic synthesis of phenols mediated by visible light using KI as catalyst

A transition-metal-free hydroxylation of iodoarenes to afford substituted phenols is described. The reaction is promoted by KI under white LED light irradiation and uses atmospheric oxygen as oxidant. By the use of triethylamine as base and solvent, the corresponding phenols are obtained in moderate to good yields. Mechanistic studies suggest that KI and catalysis synergistically promote the cleavage of C-I bond to form free aryl radicals.

Catalyst-free rapid conversion of arylboronic acids to phenols under green condition

A catalyst-free and solvent-free method for the oxidative hydroxylation of aryl boronic acids to corresponding phenols with hydrogen peroxide as the oxidizing agent was developed. The reactions could be performed under green condition at room temperature within very short reaction time. 99% yield of phenol could be achieved in only 1 min. A series of different arenes substituted aryl boronic acids were further carried out in the hydroxylation reaction with excellent yield. It was worth nothing that the reaction could completed within 1 min in all cases in the presence of ethanol as co-solvent.

The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes

An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.

Cu2O/TiO2 as a sustainable and recyclable photocatalyst for gram-scale synthesis of phenols in water

A green and straightforward protocol was developed for the synthesis of phenols from aryl boronic acid using an inexpensive and available Cu2O/TiO2 photocatalyst under visible light and sunlight. This approach proceeded in mild reaction conditions in water and the presence of air as a green oxidant, resulting in the corresponding phenols in good to excellent yields. Sunlight was also a sustainable source for this photochemical reaction. Heterogeneous nano photocatalyst was successfully recovered in 8 consecutive runs. It is noteworthy that, the photocatalyst exhibited high activity for the large-scale synthesis of phenols.