Phenol type condensations

The first large scale application of ion exchange to effluent treatment was in the recovery of water, ammonia, and basic copper sulfate from the waste streams encountered in the cuprammonium rayon process. Originally a phenolic type condensation resin was employed, but more recently carboxylic acid acrylic-based exchangers have been introduced. A similar process exists for zinc recovery from the spinning acids of viscose rayon plants, except that in this operation a sulfonic acid resin is employed. 

Since the last edition several new materials have been aimounced. Many of these are based on metallocene catalyst technology. Besides the more obvious materials such as metallocene-catalysed polyethylene and polypropylene these also include syndiotactic polystyrenes, ethylene-styrene copolymers and cycloolefin polymers. Developments also continue with condensation polymers with several new polyester-type materials of interest for bottle-blowing and/or degradable plastics. New phenolic-type resins have also been announced. As with previous editions I have tried to explain the properties of these new materials in terms of their structure and morphology involving the principles laid down in the earlier chapters. 

The first step in the sequence may involve Friedel-Crafts-type condensation of resorcinol with the enolate of 10 to afford the unsaturated ester, 11. Alkylation of the free phenol on 12 by means of ethyl bromoacetate affords chromonar (13). ... 

A process for separating crude oil emulsions of the water-in-oil type based on certain ethylene oxide-propylene oxide block pol5miers and certain poly-glycidol ethers of phenol-formaldehyde-condensation products has been described [1026-1028]. 

A Friedel-Crafts-type reaction of phenols under basic conditions is also possible. Aqueous alkaline phenol-aldehyde condensation is the reaction for generating phenol-formaldehyde resin.34 The condensation of phenol with glyoxylic acid in alkaline solution by using aqueous glyoxylic acid generates 4-hydroxyphenylacetic acid. The use of tetraalkylammonium hydroxide instead of sodium hydroxide increases the para-selectivity of the condensation.35 Base-catalyzed formation of benzo[b]furano[60]- and -[70]fullerenes occurred via the reaction of C60CI6 with phenol in the presence of aqueous KOH and under nitrogen.36... 

The technical uses of phenol are important, particularly in the manufacture of salicylic add (Chap. VI. 4, p. 249), and in that of the valuable synthetic resins of the bakelite type (condensation with formaldehyde). Under mild conditions phenol may be caused to combine with formaldehyde giving p-hydroxybenzyl alcohol ... 

The kinetic data for phenol—acetone condensation to bisphenol A [reaction type (E)] in the liquid phase at 91°C over sulphonated ion exchanger [385] were best represented by the equation... 

A number of early homogeneous membranes were made by simple condensation reactions of suitable monomers, such as phenol-formaldehyde condensation reactions of the type ... 

Besides alkoxides, acetylacetonates are also used as the starting materials for the synthesis of oxides. Titania (anatase) is obtained by decomposition of titanium oxyacetylacetonate (TiO(acac)2) in toluene at 300°C. Similarly solvothermal treatment of Fe(lll) acetylacetonate in toluene yields microcrystalline magnetite. One of the drawbacks of the use of acetylacetonate may be formation of various high boiling point organic by-products via aldol-type condensation of the acetylacetone. Actually more than 50 compounds are detected by gas chromatography-mass spectrometry (GC-MS) analysis of the supernatant of the reaction, some of which are phenolic compounds and are hardly removed from the oxide particles by washing with acetone. ... 

Calixarenes are macrocyclic molecules synthesized with high yield by condensation of appropriate arenes and aldehyde derivatives. Calix means bowF in Latin and Greek, and this phrase reflects the shape of the tetramer, which usually adopts a bowl or beaker-like conformation. Gutsche first introduced the name calixarene for this class of compounds [38]. Several authors have exhaustively reviewed the chemistry and synthetic procedures, which lead to different structural modifications of calixarenes [39-42]. In general, three types of calixarenes derivatives are known first, metacyclophanes (type 1) second, those obtained by condensation of formaldehyde with phenol (type 11), and third, those obtained by reaction with resorcinol (type III) (Scheme 6). The latter modifications are also called resorcarenes to distinguish calixarenes of type III from those of type II. 

Humic substances are high-molecular cyclic compounds representing a complex of organic substances as products of condensation of phenol-type aromatic substances with amino acids and proteins. The amount of humic substances in soil ranges from 0 to 5%, and in peat from 40 to 55%. 

In the synthesis of coumarins by the von Pechmann reaction, a spiro-compound (251) was simultaneously formed from 4-chloro-2-methylphenol (and from 2,3,5-trimethylphenol). A possible mechanism for this reaction involves the formation of the lactone (252), which reacts with another molecule of the phenol. The condensation of the dicyano-ester (253) [obtained from malononitrile and ethyl cyanoacetate] with substituted o-hydroxybenzaldehydes yields substituted coumarinimines, e.g. (254).A series of 4,6,7-substituted coumarins have been prepared and assessed for their suitability in fluorescence labelling of polymers. Esters of the type PhCH CRCOaAr react with AICI3 to give coumarins, which are probably formed via dihydrocoumarins (255) by dearylation. ... 

In a positive-tone resist, the areas that are exposed to the radiation develop away into the solvent faster than unexposed areas, resulting in a positive-tone image of the mask. The majority of commercial, positive-tone, nonchemically amplified resists used today are variations of the well-known, two-component, diazonaphthoquinone-novolac resist [5]. Novolac is a name generally given to acid-catalyzed phenol formaldehyde condensation polymers of the type shown in Fig. 2. 

Phenolic ion exchangers derived from a phenol-formaldehyde condensation reaction appeared in the first generation of ion-exchange polymers. More recently, styrene-divinylbenzene copolymers incorporating azo-substituted cresol and salicylic acid, catechol, hydroquinone, and benzoquinone have been described. The quinone-type polymers selectively sorb Hg(III) and the catechol resins sorb Cr(VI). 

Cresol resin n. A phenolic-type resin obtained by condensing a cresol with an aldehyde. 

Xylenol resin A phenolic-type resin produced by condensing xylenol (3,5-dimethylphenol) with an aldehyde. Polyphenylene oxide is made from 2,6-xylenol. 

There are two types of phenol-formaldehyde condensation polymers resoles and novolacs (117). Phenol-formaldehyde polymers prepared from the base-catalyzed condensation of phenol and excess formaldehyde are called resoles. In most phenolic resins commonly used with epoxies, the phenolic group is converted into an ether to give improved alkali resistance. At elevated temperatin-es (>150°C), resole resins react with the hydroxyl groups of the epoxy resins to provide highly cross-linked polymers. 

Tannins are considered polyphenols due to the large number of phenolic rings in their structures (Mosiewicki et al., 2007 Moubarik et al., 2009). These natural products can be found in certain plant tissues, such as bark, fruit and wood, and can be removed from these sourees by extraction with water. Tannins are classified in two groups hydrolyzable tannins and condensed tannins (Mueller-Harvey, 2001). The condensed tannins are flavonoids with complex structures (Fig. 2.5). The phenolic groups present in tannin enable this macromolecule to participate in the same reactions as phenol (Tondi and Pizzi, 2009). Condensed tannins are more suitable than the hydrolyzable type for use in the manufacture of a phenolic-type polymeric matrix due to the presence of phenolic rings with a greater number of free positions where the electrophilic attack can occur (Barbosa et al., 2010). The high reactivity of... 

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