Formaldehyde, poly condensation with

Fig. 10. Specific rotatory power changes of A -benzoyl-L-tyrosine----------and of its poly condensates with formaldehyde (XVIII) as a function of the degree of neutralization a (-----polymer...

The anion-exchange membrane is prepared from alkylene poly amines likewise condensated with formaldehyde (7, 62). 

Some polymers containing heterocycles can be included in resins following further condensation. This is possible, for example, for poly(furfuryl alcohol), which can condense with formaldehyde, phenol, melamine and urea. Furfuryl alcohol-formaldehyde copolymer can be synthesized in the reaction of furfuryl alcohol with formaldehyde in the presence of oxalic acid as catalyst. 

There are many practical uses for products from reactions of poly(vinyl alcohol). Among them are commercial preparations of poly(vinyl acetal)s formed through condensations with aldehydes. Two materials that are currently being marketed are poly(vinyl formal) and poly(vinyl butyral). The first is formed from partially hydrolyzed poly(vinyl acetate) that is dissolved in aqueous acetic acid and excess formaldehyde. The mixture is heated, sulhiric acid is added, and the reaction is allowed to proceed at 70-90 °C for 6 hours. Sulfuric acid is then neutralized and the formal precipitates out (see also Chapter 5). 

Similar poly-condensation reactions can be carried out also with oxy-acids, amines and acids, urea or phenol and formaldehyde, etc. they yield in part chain and in part reticulate products, which have been discussed, particularly by W. H. Carothers and his collaborators. A more detailed description of such products will be given in another volume of this series (comp, also vol. I). The mechanism of such processes will likewise be discussed more extensively in another volume. 

Pekala RW (1989) Organic aerogels from the poly condensation of resorcinol with formaldehyde. J Mater Sci 24 3221-3227. 

Method of synthesis reaction of urea with formaldehyde dissolved in water (45-50% solution) to hydroxymethylated urea used for subsequent poly condensation ... 

In Spite of this similarity, a conformational origin was not retained and further investigations led us to conclude that the peculiar ORD behavior of the polymer prepared in acidic medium resulted from a secondary reaction during poly condensation. This reaction, specific to the acidic medium, consists in the addition of one molecule of formaldehyde to the NH of sulfonamide groups with further cyclization with a proton of the aromatic ring to give an A -tosyl-7-hydroxy-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivative. Actually during the polycondensation, only part of the monomeric units were affected and a copolymer (VIII) was obtained, the composition of which depends on the molar ratio of formaldehyde to A-tosyl-L-tyrosine used for polycondensation [37]... 

In the development of a reactive non-chrome post-treatment, a variety of phenolic resins were synthesized and commercial phenolic resins evaluated. It was found that phenol-formaldehyde resins, creso1-forma1dehyd e condensates, ortho-novo 1 ak resins, and phenol-formaldehyde emulsions gave positive results when employed as post-treatments over zinc and iron phosphate conversion coatings. The above materials all possessed drawbacks. The materials in general have poor water solubility at low concentrations used in post-treatment applications and had to be dried and baked in place in order to obtain good performance. The best results were obtained with poly-4-vinylphenol and derivatives thereof as shown in the following structure (8,9,10)... 

A suggestion was made to name condensation polymers synthesized from two different monomers by following the prefix poly with parentheses enclosing the names of the two reactants, with the names of the reactants separated by the term -co-. Thus, the polymer in Eq. 1-7 would be named poly(phenol-co-formaldehyde). This suggestion did not gain acceptance. 

Fastness Improvement. The wetfastnesses of dyeings on wool that has been chlorinated to prevent felting and has received a finish with synthetic resin (poly-amide-epichlorohydrin or polyurethane superwash wool) can be increased by means of methylol amide compounds. Both fastness and antifelting finish can be improved through the application of a polyquatemary compound [88]. Anionic condensation products such as aromatic sulfonic acids with formaldehyde can form a barrier at the surface of the fiber and thus diminish the bleeding of anionic dyes. 

However, the most important furan resins are those produced with 2-furfuryl alcohol, for example, the 2-furfuryl alcohol-formaldehyde-based resins, which are normally synthesized by a condensation reaction catalyzed by acidic sites and promoted by heat [224] or the poly(furfuryl alcohol) thermosetting resin that is usually synthesized by the cationic condensation of its monomer 2-furfuryl alcohol, which polymerizes exothermically in the presence of a catalyst such as acid and iodine in methylene chloride, producing black, amorphous, and branched and/or cross-linked structures [225],... 

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],... 

Formaldehyde polymerization has been studied in the liquid state, in solution of protic or aprotic solvents and in the gaseous state where gaseous formaldehyde forms directly crystalline polymer. It has been studied with anionic and cationic initiators and by high energy radiations. Although there are more than 100 MM lbs. of poly form aldehyde produced per year, very few papers have been published that are actually concerned with the kinetics of formaldehyde polymerizations. The reason for this lack of detail is understandable when one realizes how difficult it is to obtain pure formaldehyde (with impurities of less than 100 p.p.m). Even pure formaldehyde undergoes side reactions and self condensation which cause new introduction of impurities. 

The first stage in the production of MDI (9d) is condensation between aniline and formaldehyde, in the presence of HC1, under subatmospheric pressure, at 70-105 °C. This affords 4,4, 2,4 and 2,2 isomers of diaminodiphenylmethane (9a, 9b and 9c). Reaction with phosgene in an inert solvent, such as chlorobenzene, first at low temperature, and then heating to 120 °C, gives, for the 4,4 isomer (9a), MDI, trimers, tetramers and higher oligomers, the latter known as poly-MDI or PMDI. Continuous liquid-phase phosgenation is favored. 

As with condensation polymers many examples of biochemically formed vinyl addition polymers, such as the poly-cis-isoprene found in the sap of rubber trees, were known long before we were able to replicate these materials even in the laboratory. Our ability to initiate and control the preparation of vinylic polymers on a laboratory scale came in the early 1930s, substantially later than the commercialization of phenol-formaldehyde condensation polymers. Since then, however, starting with the synthesis of polyethylene, then poly(vi-nyl chloride) (PVC), synthetic rubbers and polystyrene, the scale of production of this class of polymer has outstripped the polycondensation class by more than an order of magnitude. Table 23.1 displays some representative production figures to illustrate this. 

Yaginuma patented interfacial membranes made by condensation of poly-alicyclic diisocyanates and diacyl halides with polyethylenimine or polyepia-mine.44 This approach was claimed to provide high organic rejections simultaneously with low salt rejections, whereas comparative data for typical aromatic diisocyanates or diacyl halides showed high rejections for both types of solutes. However, only a wastewater product, naphthalenesulfonic acid/formaldehyde condensate, was used in the testing of such membranes. 

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