Reaction with polyhydric alcohols

Approximately 65% of the PO produced is used for the synthesis of polyether polyols (in a reaction with polyhydric alcohols), one of the main components used in the manufacture of polyurethanes, propene glycol (20%), glycol ethers (5%) and butanediol, amongst others. Figure 6.1 shows an overview of the PO industry. 

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. 

As a dibasic acid, malic acid forms the usual salts, esters, amides, and acyl chlorides. Monoesters can be prepared easily by refluxing malic acid, an alcohol, and boron trifluoride as a catalyst (9). With polyhydric alcohols and polycarboxyUc aromatic acids, malic acid yields alkyd polyester resins (10) (see Alcohols, polyhydric Alkyd resins). Complete esterification results from the reaction of the diester of maUc acid with an acid chloride, eg, acetyl or stearoyl chloride (11). 

Esterification is one of the most important reactions of fatty acids (25). Several types of esters are produced including those resulting from reaction with monohydric alcohols, polyhydric alcohols, ethylene or propylene oxide, and acetjiene or vinyl acetate. The principal monohydric alcohols used are methyl, ethyl, propyl, isopropyl, butyl, and isobutyl alcohols (26) (see Esterification Esters, organic). 

By organic chemistry formalism, polyacetals are reaction products of aldehydes with polyhydric alcohols. Polymers generated from aldehydes, however, either via cationic or anionic polymerization are generally known as polyacetals because of repeating acetal linkages. Formaldehyde polymers, which are commercially known as acetal resins, are produced by the cationic ring opening polymerization of the cyclic trimer of formaldehyde, viz., trioxane [29-30] (Fig. 1.5). 

Thermosetting space-network polymers can be prepared through the reaction of polybasic acid anhydrides with polyhydric alcohols. A linear polymer is obtained with a bifunctional anhydride and a bifunctional alcohol, but if either reactant has three or more reactive sites, then formation of a three-dimensional polymer is possible. For example, 2 moles of 1,2,3-propane-triol (glycerol) can react with 3 moles of 1,2-benzenedicarboxylic anhydride (phthalic anhydride) to give a highly cross-linked resin, which usually is called a glyptal ... 

Interest in the xanthates of carbohydrates has arisen almost entirely through the importance of the viscose process in the technical production of rayon and related products.126 The selective character of the reaction of carbon disulfide and alkali with polyhydroxy compounds has been studied. Lieser and Nagel126 found that a monoxanthate is formed with polyhydric alcohols and methyl a-D-glucopyranoside when they react with carbon disulfide and aqueous barium hydroxide. The xanthation that has been demonstrated in the cases of glycerol 1,3-dimethyl ether and levoglucosan (LXIX) shows that secondary hydroxyl groups can... 

The reactions of polyhydric alcohols with the hydroxyl radical in aqueous solution have been extensively studied (e.g. in radiolytic and biomimetic systems), mainly because of their suitability as models for more complicated carbohydrate substrates [55] or enzymatic systems involving glycol-type radicals [56, 57]. Because there are no double bonds to which OH could add, only H-abstraction reactions are possible. Because the C-H bond energy is significantly lower than the 0-H bond energy, it is the carbons from which H are abstracted and not the alcohol function. In this type of reaction, a,yS-dihydroxyalkyl radicals are formed. The same radicals could, in principle, be produced by addition of "OH to enols, see Scheme 2, lower part. This shows the complementarity of H-abstraction and OH-addition and thereby the relevance of the former to one-electron oxidation of olefinic bonds (Scheme 2). 

In 1952, a number of publications appeared which showed that, in the presence of alkaline borate, a wide variety of neutral carbohydrates migrate toward the anode in zone electrophoresis. It is of interest to note that Coleman and Miller, in 1942, had observed the migration of n-glu-cose and maltose toward the anode when a potential was applied across their solution in aqueous borax. The reaction of polyhydric alcohols with borate ions has long been knowrf and it has been suggested that the following equilibria occur. 

The diisocyanates are used mainly in the manufacture of polyurethanes (PUR). These are produced by polyaddition of diisocyanates and dihydric alcohols, in particular the polyether alcohols (i.e., polyethylene glycols, polypropylene glycols, and the reaction products of propylene oxide with polyhydric alcohols). In addition, oligomeric esters from dicarboxylic acids and diols (polyester alcohols) are also used [91] ... 

Alkyd resins have been defined as the reaction product of a polybasic acid and a polyhydric alcohol. This definition Includes polyester resins of which alkyds are a particular type. The specific definition that has gained wide acceptance is that alkyds are polyesters modified with monobasic fatty acids. In recent years, the term nonoil or oil-free alkyd has come into use to describe polyesters formed by the reaction of polybasic acids with polyhydric alcohols in non-stoichlometric amounts. These products are best described as functional saturated polyesters containing unreacted OH and/or COOH groups, and they are finding rapidly increasing uses in organic coatings. 

The reaction of halogenosilanes with polyhydric alcohols leads quite often to oligomers. Thus, the reaction of ethylene glycol (699) with dichlorodimethysilane (117) affords the ten-membered 2,2,7,7-tetramethyl-l,3,6,8-tetroxa-2,7-disilacyclodecane (700) (equation 356)392. 

Acetylene reacts with polyhydric alcohols, and -hydroxy acids and their derivatives.197 In these reactions 1,2-, 1,3-, and 1,4-diols give cyclic glycols preferentially.197,201,202... 

Polyhydric alcohol esters. Reactions of fatty acids with polyhydric alcohols derived from reduction of sugars such as sorbitol results in a mixtnre of esters of both the sorbitol and its dehydrated ethers sorbide and isosorbide. Ethoxylation of this complex mixtnre of esters involves insertion of ethoxylation and transesterification ethoxylation as described earlier, resulting in a highly complex composition with performance properties that are dependent on the precise conditions for both the esterification and the ethoxylation steps. This is described classically as a product-by-process, which is difficult to reproduce due to the affect of the commercial-scale manufacturing kit on the precise conditions of each step of the reaction. 

Chemically, all alkyds are polyesters and are derived from a polycondensation reaction of polyhydric alcohols and polybasic acids with a certain degree of modification by some kind of oil or fatty acid. Among the important chemical reactions involved in alkyd resin technology are direct esterification of carboxylic acids with alcoholic hydroxyl groups, transesterification reactions, and reaction of an alcoholic hydroxyl with an acid anhydride. These reactions are shown in Figure 2.7. 

Esterification with acid anhydrides is very widespread, especially for preparative use. Acetyl derivatives are prepared by reacting alcohols with acetic anhydride for identification purposes this method is mainly used with polyhydric alcohols (see p. 311) and with higher-molecular alcohols (sterols, etc.). The alcohol is heated in acetic anhydride, usually in the presence of anhydrous sodium acetate, or also in pyridine, chloroform, or benzene solutions. The isolation is carried out either by diluting the reaction... 

A major contribution of naval stores products to the coatings industry occurred in the 1920s and 1930s with the production of alkyd resins from the reaction of polyhydric alcohols, viz., glycerol and pentaerythritol with rosin-maleic and terpene-maleic Diels-Alder condensation products. The name alkyd was coined by Kienle (Simonsen et al, 1947-1952) in 1927. 

Polyhydric alcohol mercaptoalkanoate esters are prepared by reaction of the appropriate alcohols and thioester using -toluenesulfonic acid catalyst under nitrogen and subsequent heating (16,17). Organotin mercapto esters are similarly produced by reaction of the esters with dibutyltin oxide (18). Pentaerythritol can be oxidized to 2,2-bis(hydroxymethyl)hydracryhc acid [2831-90-5] C H qO, ... 

The reaction of formate salts with mineral acids such as sulfuric acid is the oldest iadustrial process for the production of formic acid, and it stiU has importance ia the 1990s. Sodium formate [141-53-7] and calcium formate [544-17-2] are available iadustriaHy from the production of pentaerythritol and other polyhydric alcohols and of disodium dithionite (23). The acidolysis is technically straightforward, but the unavoidable production of sodium sulfate is a clear disadvantage of this route. 

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). 

Alkyd resins are produced by reaction of a polybasic acid, such as phthaUc or maleic anhydride, with a polyhydric alcohol, such as glycerol, pentaerythritol, or glycol, in the presence of an oil or fatty acid. The resulting polymeric material can be further modified with other polymers and chemicals such as acryhcs, siUcones, and natural oils. On account of the broad selection of various polybasic acids, polyhydric alcohols, oils and fatty acids, and other modifying ingredients, many different types of alkyd resins can be produced that have a wide range of coating properties (see Alkyd resins). 

Poly(vinyl alcohol) participates in chemical reactions in a manner similar to other secondary polyhydric alcohols (82—84). Of greatest commercial importance are reactions with aldehydes to form acetals, such as poly(vinyl butyral) and poly(vinyl formal). 

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. 

Epoxide resins are essentially long-chain polyhydric alcohols with epoxide groups at either end. They make useful building blocks because both the hydroxyl and the epoxide groups are available for reaction with other compounds. 

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