Carboxylic acid anhydrides with phenols

Photocationic initiators. Epoxy resins can be cross-linked by compounds containing active hydrogen, e.g., carboxylic acids, anhydrides, amines, phenols etc., or by the ionic polymerization process. Lewis acids such as BF3 and usually a crystalline complex of BF3 with amines, e.g., BF3 NH2C2H5, can be used for curing reaction at 80-100° C [124]. 

Acylatmg agents such as acyl chlorides and carboxylic acid anhydrides can react with phenols either at the aromatic ring (C acylation) or at the hydroxyl oxygen (O acylation)... 

The O acylation of phenols with carboxylic acid anhydrides can be conveniently catalyzed m either of two ways One method involves converting the acid anhydride to a more powerful acylatmg agent by protonation of one of its carbonyl oxygens Addi tion of a few drops of sulfuric acid is usually sufficient... 

Carboxylic acids react with trifluoroacetic anhydride to give mixed anhydrides that are especially useful for the acylation of hindered alcohols and phenols ... 

Hill, C.A.S. and Papadopoulos, A.N. (2002). The pyridine-catalysed acylation of pine sapwood and phenolic model compounds with carboxylic acid anhydrides. Determination of activation energies and entropy of activation. Holzforschung, 56(2), 150-156. 

It is possible to prepare esters of phenols with carboxylic acid anhydrides or acid halides, and phenyl ethers by reaction of benzenolate anion with halides, sulfate esters, sulfonates, or other alkyl derivatives that react well by the SN2 mechanism ... 

BenzeylatUnn. Reaction of 1 with carboxylic acids, amines, and phenols produces mixed anhydrides, benzamides, and benzoate esters, respectively, in good yield. These reactions can also be carried out using C6H5COCI and 0.3 equiv. of 2 in place of preformed 1. ... 

Phosgene is reported to combine with a wide range of oxygenated materials, including alcohols, ethers, ketones, carboxylic acids, anhydrides, lactones, esters, carbonic acid derivatives, etc. Only the reactions of COCIF with alcohols, phenols and cyclic ethers have been reported, resulting usually in the generation of fluoroformates. Such materials can often be usefully converted into the corresponding fluoro compound by means of decarboxylation in the presence of BF3, EtjO, pyridine, or other materials. 

The Fries rearrangement is the acid-catalyzed transformation of aryl esters into hydroxy ary Iketones [1] and often plays an important role in the production of hydro-xyarylketones by acylation of phenols with carboxylic acids, anhydrides, or acyl chlorides. 

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. 

Phenols react with carboxylic acid anhydrides and acid chlorides to form esters. These reactions are quite similar to those of alcohols (Section 17.7). 

The various methods of carbon oxidation discussed in Section 13.1 result in a variety of functional surface groups. These include carboxylic acids, anhydrides, lactones, carbonyls, aldehydes, esters, and phenols. The quantity and type of functionalities formed vary depending on the oxidation procedure and the prevailing reaction conditions. Eor example, wet chanical oxidation with nitric acid tends to yield more carboxylic acids, whereas gas-phase oxidation yields more anhydrides, lactones, phenols, and carbonyls [129]. 

Group of plastics composed of resins produced by reactions of epoxides or oxiranes with compounds such as amines, phenols, alcohols, carboxylic acids, acid anhydrides and unsaturated compounds. 

Thionyl chloride is another activating agent employed for reactions between aromatic carboxylic acids and phenols in pyridine solution. The mechanism suggested does not involve the formation of an acid chloride but assumes the existence of an intermediary mixed sulfinic anhydride which undergoes reaction with phenolic endgroups (Scheme 2.32).311... 

Finally, a new water-soluble polyphosphazene was recently synthesized that has the structure shown in 36 (46). This polymer has two attributes as a biomedical macromolecule. First, the pendent carboxylic acid groups are potential sites for condensation reactions with amines, alcohols, phenols, or other carboxylic acid units to generate amide, ester, or anhydride links to polypeptides or bioactive small molecules. Second, polymer forms ionic crosslinks when brought into contact with di- or trivalent cations such as Ca or Ai3+. The crosslinking process converts the water-soluble polymer to a hydrogel, a process that can be reversed when the system... 

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