Coating 2,6-dimethylphenol

For a capillary column, quality is also measured by the use of a standardized test mix, developed by Grob et al. (Figure 6). This mix is intended to provide qualitative information about the stationary phase coating, and in particular activity toward certain solutes. Thus, the mixture contains 2,3-butanediol, -decane, 1-octanol, nonanal, 2,6-dimethylphenol, 2-ethylhexanoic acid, 2,6-dimethylaniline, -dodecane,... 

Polyphenylene oxide (PPO) ru A thermoplastic, linear, non-crystalline polyether obtained by the oxidative polycondensation on 2,6-dimethylphenol in the presence of a copper-amine complex catalyst. The resin has a wide useful temperature range, from below —170 to +190°C, with intermittent use to 205° C possible. It has excellent electrical properties, unusual resistance to acids and bases, and is pro-cessable on conventional extrusion and injection-molding equipment. Because of its high coat PPO is also marketed in the form of polystyrene blends (see Noryf ) that are lower-softening (Tg of PS is about 100°C vs 208°C for PPO), and have working properties intermediate between those of the two resins. 

Heat resistant poly(oxyphenylene) coatings have also been pr ued by the electrochemical initiation of the polymerization of 2,6-dimethylphenol in the presence of Cu(OAc)2 in admixture with traces of Cua l While the inediation of cupric-cuprous couple in the oxidaticm rracticMi can be surmised, the details of the mechanisms of the polymerization are not e blished. 

There are six isomeric xylenols (dimethylphenols) (II). At one time, mixtures of the isomers were obtained from coal tar and petroleum refining streams but now xylenols are obtained mainly by the alkylation of phenol with methanol (see, for example, section 12.6.1). For the preparation of resins, 3,5-xylenol is the preferred isomer because it has three reactive positions. Xylenols are used for making oil-soluble phenolic resins for surface coatings. They are also used for making alkali-resistant grades of resins for moulding powders and laminates. 

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