Bisphenol formaldehyde reaction

Quinone dioximes, alkylphenol disulfides, and phenol—formaldehyde reaction products are used to cross-link halobutyl mbbers. In some cases, nonhalogenated butyl mbber can be cross-linked by these materials if there is some other source of halogen in the formulation. Alkylphenol disulfides are used in halobutyl innerliners for tires. Methylol phenol—formaldehyde resins are used for heat resistance in tire curing bladders. Bisphenols, accelerated by phosphonium salts, are used to cross-link fluorocarbon mbbers. 

The diarylation reaction is especicdly common with phenols (the diaryl product here is called a bisphenol). The reaction is normally carried out in alkaline solution on the phenolate ion. The hydroxymethylation of phenols with formaldehyde is called the Lederer-Manasse reaction. This reaction must be carefully controlled, since it is possible for the para and both ortho positions to be substituted and for each of... 

In 1843, Pira [1] reported that phenol alcohols are converted to resins (called saliretins) on heating. Baeyer [2] in 1872 reported that the reaction of phenols with acetaldehyde in the presence of acid catalysts also gives resinous products. Kleeberg [3] in 1891 reported that formaldehyde undergoes similar reactions. However, Dianin [4, 5] found that acetone reacts with phenol to give a crystalline bisphenol (now known as bisphenol A). In 1874 Lederer [6] and Manasse [7] independently synthesized o-hydroxybenzyl alcohol (saligenin) by the low-temperature alkaline-catalyzed formaldehyde reaction. 

The most important commercial chemical reactions of phenol are condensation reactions. The condensation reaction between phenol and formaldehyde yields phenoHc resins whereas the condensation of phenol and acetone yields bisphenol A (2,2-bis-(4-hydroxyphenol)propane). PhenoHc resins and bisphenol A [80-05-7] account for more than two-thirds of U.S. phenol consumption (1). 

The in situ process is simpler because it requires less material handling (35) however, this process has been used only for resole resins. When phenol is used, the reaction system is initially one-phase alkylated phenols and bisphenol A present special problems. As the reaction with formaldehyde progresses at 80—100°C, the resin becomes water-insoluble and phase separation takes place. Catalysts such as hexa produce an early phase separation, whereas NaOH-based resins retain water solubiUty to a higher molecular weight. If the reaction medium contains a protective coUoid at phase separation, a resin-in-water dispersion forms. Alternatively, the protective coUoid can be added later in the reaction sequence, in which case the reaction mass may temporarily be a water-in-resin dispersion. The protective coUoid serves to assist particle formation and stabUizes the final particles against coalescence. Some examples of protective coUoids are poly(vinyl alcohol), gum arabic, and hydroxyethjlceUulose. 

Uses. The major applications of phenol are phenolic resins, Bisphenol A, and caprolactam. The reaction of phenol with formaldehyde gives liquid phenolic resins (used extensively as the adhesive in plywood) and solid resins (used as engineering plastics in electrical applications). In powder form, the phenolic resin can be molded easily and are completely nonconductive. These phenolic resins or plastics can be found in panel boards, switchgears, and telephone assemblies. The agitator in your washing machine is probably a phenolic resin. 

As industrial relevant Friedel-Crafts reaction, the synthesis of Bisphenol-F, a material for epoxy resin, from phenol and formaldehyde was chosen [57]. This reaction involves formation of higher order condensates such as tris-phenols. To minimize the latter, the molar ratio of phenol to formaldehyde is set to a very high value (30-40), which is more than 15 times larger than the amount theoretically necessary. Three types of micromixers were used. These are a T-shaped mixer with 500 pm inner diameter, a multilaminating interdigital micromixer with 40 pm channels and a so-called self-made K-M micromixer with center collision mixing. 

Bisphenol F Resins. Diglycidyl ether resins based on bisphenol F (DGEBF) have been developed to provide cured epoxy resins with greater flexibility and lower softening temperatures than conventional DGEB A epoxy resins. The preparation of bisphenol F resins is from formaldehyde and phenol. Three isomers are possible because substitution can occur at the ortho-, meta-, or para- positions. The proportion of isomers depends upon the pH of the reaction medium. 

One of the earliest commercial plastics was Bakelite , formed by the reaction of phenol with a little more than one equivalent of formaldehyde under acidic or basic conditions. Baeyer first discovered this reaction in 1872, and practical methods for casting and molding Bakelite were developed around 1909. Phenol-formaldehyde plastics and resins (also called phenolics) are highly cross-linked because each phenol ring has three sites (two ortho and one para) that can be linked by condensation with formaldehyde. Suggest a general structure for a phenol-formaldehyde resin, and propose a mechanism for its formation under acidic conditions. (Hint Condensation of phenol with formaldehyde resembles the condensation of phenol with acetone, used in Problem 26-17, to make bisphenol A.)... 

The first synthetic polymers to be of any use were the phenol formaldehyde resins of which the most famous, Bakelite, was discovered by Bakeland at the turn of the century. He combined phenol and formaldehyde in acid solution and got a reaction that starts like the bisphenol A synthesis. 

The telechelica,(i -bis(2,6-dimethylphenol)-poly(2,6-dimethylphenyl-ene oxide) (PP0-20H) [174-182] is of interest as a precursor in the synthesis of block copolymers [175] and thermally reactive oligomers [179]. The synthesis has been accomplished by five methods. The first synthetic method was the reaction of a low molecular weight PPO with one phenol chain end with 3,3, 5,5 -tetramethyl-l,4-diphenoquinone. This reaction occurred by a radical mechanism [174]. The second method was the electrophilic condensation of the phenyl chain ends of two PPO-OH molecules with formaldehyde [177,178], The third method consists of the oxidative copolymerization of 2,6-dimethylphenol with 2,2 -di(4-hydroxy-3,5-di-methylphenyl)propane [176-178]. This reaction proceeds by a radical mechanism. A fourth method was the phase transfer-catalyzed polymerization of 4-bromo-2,6-dimethylphenol in the presence of 2,2-di(4-hy-droxy-3,5-dimethylphenyl)propane [181]. This reaction proceeded by a radical-anion mechanism. The fifth method developed was the oxidative coupling polymerization of 2,6-dimethylphenol (DMP) in the presence of tetramethyl bisphenol-A (TMBPA) [Eq. (57)] [182],... 

In contrast to aliphatic alcohols, which are mostly less acidic than phenol, phenol forms salts with aqueous alkali hydroxide solutions. At room temperature, phenol can be liberated from the salts even with carbon dioxide. At temperatures near the boiling point of phenol, it can displace carboxylic acids, e.g. acetic acid, from their salts, and then phenolates are formed. The contribution of ortho- and -quinonoid resonance structures allows electrophilic substitution reactions such as chlorination, sulphonation, nitration, nitrosation and mercuration. The introduction of two or three nitro groups into the benzene ring can only be achieved indirectly because of the sensitivity of phenol towards oxidation. Nitrosation in the para position can be carried out even at ice bath temperature. Phenol readily reacts with carbonyl compounds in the presence of acid or basic catalysts. Formaldehyde reacts with phenol to yield hydroxybenzyl alcohols, and synthetic resins on further reaction. Reaction of acetone with phenol yields bisphenol A [2,2-bis(4-hydroxyphenyl)propane]. 

Hydrolysis has been the main method used for the chemical recycling of other condensation polymers, such as polyacetals and polycarbonates. Hydrolysis of polyacetals leads back to the starting monomers, formaldehyde or trioxane. Polycarbonates are polymers synthesized by the reaction of phosgene and a dihydric phenol, commonly bisphenol A. Chemical recycling of polycarbonate... 

Although only cardol in CNSL has bifunctionality, attempts have been made to modify cardanol to the same effect. Thus reaction of (15 1)-cardanol with phenol in the presence of boron trifluoride afforded the 1,8-bis(hydroxyphenyl)pentadecane structure (ref. 261). Reaction then with a molar proportion of epichlorhydrin and polymerisation resulted in final products considered to be superior in properties to and cheaper than those derived from bisphenol A. The corresponding fully saturated cardbisphenol compound has been converted to a water soluble bis Mannich base by reaction with diethanolamine and formaldehyde (ref. 262) of value for cathodic electrodeposition. In another case of a related bis diethanolamine product, it was found necessary to react the hydroxyl groups with the monoisocyanate resulting from treatment of tolylenediisocyanate (TDI) with a molecular proportion of cardanol (ref. 263) in order to obtain a suitable binder for... 

Epoxies can be formed from several types of monomers, but often start with epichlorohydrin and bisphenol-A, as shown in Fig. 4.11, because the costs of the ingredients are low. Again the initial reaction is carried out to a low degree of polymerization. The system is then stabilized and diluted with monomer to achieve a workable consistency. Further reaction is carried out with the addition of an amine, amide, urea-formaldehyde, or phenol-formaldehyde. 

Four reactive systems were studied at varying ratios of the two reactive components. These reactive systems were phenol, bisphenol A, trisphenol, and a mixture of bisphenol A and o-cresol (results from the latter three systems are not shown). An example of the effects of increasing (r) on the reaction time needed to reach the gel point is shown in Figure 4a for phenol. Clearly, the time required to reach the gel point decreases as the ratio of die reactants increases, as predicted by equation 2. The gel time for the other phenolic systems also decreases as the ratio of reactants increases. These model systems show that changing the ratio of reactive sites has the same impact regardless of the functionality of the phenolic system. This is very important as one tries to apply the results from model compound studies to real phenol formaldehyde adhesives that may include complex mixtures of phenolics. 

A bisphenol monomer, 2,2 -dimethylaminemethy-lene-4,4 -biphenol has been prepared by the Mannich reaction of dimethylamine and formaldehyde with 4,4 -biphenol. This monomer can be used for the synthesis of partially fluorinated PAES polymers with pendant quaternary anunonium groups. The synthesis is shown in Figure 7.2. 

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