Alcohols unsaturated polyhydric

Sulfation andSulfamation. Sulfamic acid can be regarded as an ammonia—SO. complex and has been used thus commercially, always in anhydrous systems. Sulfation of mono-, ie, primary and secondary, alcohols polyhydric alcohols unsaturated alcohols phenols and phenolethylene oxide condensation products has been performed with sulfamic acid (see Sulfonation and sulfation). The best-known appHcation of sulfamic acid for sulfamation is the preparation of sodium cyclohexylsulfamate [139-05-9] which is a synthetic sweetener (see Sweeteners). 

SYNTHESIS OF HEXITOLS AND PENTITOLS FROM UNSATURATED POLYHYDRIC ALCOHOLS... 

Unsaturated polyester (UP) resin is an unsaturated linear polyester resin polycondensed by unsaturated dibasic acid or anhydride (mainly maleic anhydride and fumaric acid), a certain amount of saturated dibasic acids (such as phthalic acid and terephthalic acid), and dihydric alcohol or polyhydric alcohols (such as ethylene glycol, propylene glycol, and glycerin). 

Polyols. Several important polyhydric alcohols or polyols are made from formaldehyde. The principal ones include pentaerythritol, made from acetaldehyde and formaldehyde trimethylolpropane, made from -butyraldehyde and formaldehyde and neopentyl glycol, made from isobutyraldehyde and formaldehyde. These polyols find use in the alkyd resin (qv) and synthetic lubricants markets. Pentaerythritol [115-77-5] is also used to produce rosin/tall oil esters and explosives (pentaerythritol tetranitrate). Trimethylolpropane [77-99-6] is also used in urethane coatings, polyurethane foams, and multiftmctional monomers. Neopentyl glycol [126-30-7] finds use in plastics produced from unsaturated polyester resins and in coatings based on saturated polyesters. 

Glycerol, the simplest trihydric alcohol, forms esters, ethers, haUdes, amines, aldehydes, and such unsaturated compounds as acrolein (qv). As an alcohol, glycerol also has the abiUty to form salts such as sodium glyceroxide (see also Alcohols, polyhydric). 

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

Alkyds. Alkyd resins (qv) are polyesters formed by the reaction of polybasic acids, unsaturated fatty acids, and polyhydric alcohols (see Alcohols, POLYHYDRic). Modified alkyds are made when epoxy, sUicone, urethane, or vinyl resins take part in this reaction. The resins cross-link by reaction with oxygen in the air, and carboxylate salts of cobalt, chromium, manganese, zinc, or zirconium are included in the formulation to catalyze drying. 

These resins are produeed by reacting a polyhydric alcohol, usually glycerol, with a polybasic acid, usually phthalic acid and the fatty acids of various oils such as linseed oil, soya bean oil and tung oil. These oils are triglycerides of the type shown in Figure 25.30. R], R2 and R3 usually contain unsaturated groupings. The alkyd resins would thus have structural units, such as is shown in Figure 25.31. 

The term alkyd is sometimes used to describe all polyesters produced from polybasic acids and a polyhydric alcohol. The terms saturated and unsaturated polyesters have been used to distinguish between those alkyd polyesters that are saturated from those that contain unsaturation. 

Alkyd resins have been the workhorse for the coatings industry over the last half century. The term alkyd was coined to define the reaction product of polyhydric alcohols and polybasic acids, in other words, polyesters. However, its definition has been narrowed to include only those polyesters containing monobasic acids, usually long-chain fatty acids. Thus thermoplastic polyesters typified by polyethylene terephthalate (PET) used in synthetic fibers, films, and plastics and unsaturated polyesters typified by the condensation product of glycols and unsaturated dibasic acids (which are widely used in conjunction with vinylic monomers in making sheet molding compounds or other thermosetting molded plastics) are not considered as part of the alkyd family and are beyond the scope of the present discussion. 

It is now clear that these alkaloids are derived from complex polyhydric amino alcohols, probably based on the formula Ci9H28-NH, and that they are thus related, formally at least, to the diterpenes (3). It is not clear, however, whether all the alkaloids have the same polycyclic skeletal stmcture some of the simpler bases are definitely pentacyclic, and the substituted CieHjs NH nucleus contains one unsaturated center. In most of the more complex alkaloids, however, no definite chemical proof has been given that such unsaturation is present however, the ultraviolet absorption spectra exhibit end-absorption in the region 2200-2600 a., and the presence of one inert unsaturated center may thus be presumed. It is likely, therefore, that all the bases have pentacyclic skeleta. 

The unsaturated polyester prepolymers are obtained from the condensation of polyhydric alcohols and dibasic acids. The dibasic acid consists of one or more saturated acid and/or unsaturated acid. The saturated acid may be phthalic anhydride, adipic acid, or isophthalic acid, while the unsaturated acid is usually maleic anhydride or fumaric acid. The polyhydric alcohols in common use include glycol (such as ethylene glycol, propylene glycol, diethylene glycol), glycerol, sorbitol, and pentaeiythritol (Equation 5.1). 

In addition to phthalic esters, the most important applications for phthalic anhydride are in unsaturated polyester resins, together with alkyd resins produced by reaction with polyhydric alcohols. These polymers are used principally as raw materials in paint manufacture. 

Name given to synthetic, thermosetting resins processed from polyhydric alcohols and polybasic acid or anhydrides. These unsaturated polyesters are prepared by esterification of a polyfunctional alcohol (e.g., glycerin) with phthalic anhydride in combination with fatty acids or rosin acids (molecular weight about 2,000 to 5,000). These resins are frequently modified by incorporation of, e.g., nitrocellulose, NC, or phenolics. AUcyds are used mainly as lacquers. 

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