Alcohols with acid anhydrides

Polymer plasticization can be achieved either through internal or external incorporation of the plasticizer into the polymer. Internal plasticization involves copolymerization of the monomers of the desired polymer and that of the plasticizer so that the plasticizer is an integral part of the polymer chain. In this case, the plasticizer is usually a polymer with a low Tg. The most widely used internal plasticizer monomers are vinyl acetate and vinylidene chloride. External plasticizers are those incorporated into the resin as an external additive. Typical low-molecular-weight external plasticizers for PVC are esters formed from the reaction of acids or acid anhydrides with alcohols. The acids include ortho- and iso-or terephthalic, benzoic, and trimellitic acids, which are cyclic or adipic, azeleic, sebacic, and phosphoric acids, which are linear. The alcohol may be monohydric such as 2-ethylhexanol, butanol, or isononyl alcohol or polyhydric such as ethylene or propylene glycol. The structures of some plasticizers of PVC are shown in Table 9.1. 

Esterification (Section 17.7A) The synthesis of an ester, usually involving reactions of carboxylic acids, acid chlorides or acid anhydrides with alcohols. 

Another generally applicable method, particularly in the case of electronegative elements, is the esterifieation of their oxyacids or oxides (acid anhydrides) with alcohols (Section 2.6), and removing the water produced in the reaction continuously. 

Reaction of Acid Anhydrides with Alcohols (Method C)... 

Esters made from the reaction of acids (or anhydrides) with alcohols. 1-Alkanols produce linear chains, hence the L designation in plasticizer names. 

A few of the important reactions carboxylic acids undergo are shown above. Soap is made by reacting sodium or potassium hydroxide with long-chain acids such as C17H35COOH (stearic acid). Acid chlorides and acid anhydrides are more reactive than their corresponding carboxylic acids and are used in the chemical industry to make various acid derivatives. A very important industrial reaction is the reaction of carboxylic acids (or the chlorides or anhydrides) with alcohols to form esters. 

Carboxylic acids such as acetic acid react with alcohols such as methanol or with methoxytrimethylsilane 13 a in the presence of trimethylchlorosilane (TCS) 14 in THF or 2-methyl-THF to give esters such as methyl acetate in 97% yield and hex-amethyldisiloxane 7. Even methyl pivalate can be readily prepared in 91% yield [111]. Reaction of a variety of carboxylic acids, for example N-benzoylglycine 329, with two equivalents of yS-trimethylsilylethanol 330 and with 14 has been shown to afford esters such as 331 in 98% yield [112, 112 a]. Likewise, silylated carboxylic acids react with silylated alcohols or thiophenols in the presence of 4-trifluoro-methylbenzoic anhydride and TiCl4/AgCl04 to furnish esters or thioesters in high yields [113, 114] (Scheme 4.43). 

The inclusion of DMAP to the extent of 5-20 mol % in acylations by acid anhydrides and acyl chlorides increases acylation rates by up to four orders of magnitude and permits successful acylation of tertiary and other hindered alcohols. The reagent combination of an acid anhydride with MgBr2 and a hindered tertiary amine, e.g., ( -Pr)2NC2H5 or 1,2,2,6,6,-pentamethylpiperidine, gives an even more reactive acylation system, which is useful for hindered and sensitive alcohols.105... 

Catalysed reaction of acid chlorides and anhydrides with alcohols and phenols (Table 3.11)... 

The method described is adapted from the procedures of Kym 3 and Engelhardt, Latschinoff, and Malyscheff.4 Thio-benzoic acid has been prepared by the reaction of benzoyl chloride with potassium sulfide,4 hydrogen sulfide in pyridine,6 6 and magnesium bromide hydrosulfide.7 It is formed from dibenzoyl disulfide with potassium hydrosulfide,4 potassium hydroxide,4 8 and ammonia.9 It is also formed from dibenzoyl sulfide, from phenyl benzoate, and from benzoic anhydride with alcoholic potassium hydrosulfide.4 It has been obtained from dibenzoyl sulfide and hydrogen sulfide,10 carbon oxysulfide and phenyl-magnesium bromide,11 12 dibenzyl disulfide and sodium ethoxide,13 benzyl chloride and sulfur in the presence of potassium hydroxide,14 and benzylthiosulfuric acid and alkali.18 16... 

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 ... 

Reaction of an acid chloride (or acid anhydride) with an alcohol ... 

You need to know the structure of phosphoric acids for the MCAT. When heated, phosphoric acid forms phosphoric anhydrides. Phosphoric acids react with alcohols to form esters. 

Of practical interest are the last two techniques for producing trialkylbo-rates. It should be noted however, that the industrial reaction of boric anhydride with alcohols is fraught with difficulties. E.g., when powderlike boric anhydride is introduced into alcohol, clumps should be broken lest they kill the reaction. If boric anhydride is used in the form of pieces, the reaction should be conducted under an increased pressure and alcohol should be dehydrated beforehand. Thus, the most technological method is to obtain trialkyl(aryl)borates by the interaction of boric acid with alcohols. 

The usual reagents for acylation of steroid alcohols are acyl chlorides or acid anhydrides, in pyridine as catalyst and solvent, or acid anhydrides with mineral acids as catalyst. All secondary hydroxyl groups (except [12]) can be esterified in pyridine,... 

Acid chlorides react with sodium salts of carboxylic acids to form anhydrides, with alcohols to form esters, with water to form acids, and with amines to form amides. 

Acyl halides react with carboxylate ions to form anhydrides, with alcohols to form esters, with water to form carboxylic acids, and with amines to form amides because in each case the incoming nucleophile is a stronger base than the departing halide ion (Table 17.1). Notice that both alcohols and phenols can be used to prepare esters. 

The reaction of a cyclic acid anhydride with an alcohol produces a molecule with both an ester and carboxylic acid functionality. The mechanism for the reaction of phthalic anhydride with methanol is ... 

By treating glycine anhydride with alcoholic hydrochloric acid, glycyl-glycine ester resulted —... 

Reaction of an Acid Anhydride with an Alcohol (Section 14.4B)... 

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