Acid anhydrides with phenols

These copolymers are synthesized in the same way as poly(imide-co-amides), except in this case the precursor is a dianhydride with aromatic ester bonds, which is obtained by conversion of trimellitic acid anhydride with phenol esters ... 

The acid-base indicator phenolphthalein is a derivative of benzaurine (Scheme 6.34) Condensation of phthalic anhydride with phenol generates the colourless lactone form... 

On the other hand, epoxies cured with acid anhydrides and phenolic resins exhibit little or no reactivity when stored in direct contact with explosives and propellants. 

Reaction XXXV. (b) Condensation of Phthalic Anhydride with Phenols in the presence of Anhydrous Aluminium Chloride, s-tetrachloroethane being used as a Solvent. (B., 52, 2098 53, 826.)—This is an extension of the previous reaction to phenols employment of tetrachloroethane as solvent has enabled satisfactory yields to be obtained. Condensation takes place in the or Ao-position to the hydroxyl group. Thus phenol and phthalic anhydride yield 2-(o-hydroxybenzoyl)-benzoic acid. 

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]. 

U.S. methanol production in 1993 amounted to 4 8 Mt, but demand possibly exceeded 8 Mt, the difference being met by imports. The increased production of MTBE (methyl /-butyl ether, see section 12.9.3) appears to have consumed some 4Mt of methanol, compared with l 45Mt for formaldehyde (1-3 Mt, 100% bases) and possibly 0 7-0 8Mt for the carbonylation routes to acetic acid anhydride. (Amino-, phenolic- and polyacetal-resins accounted for 27%, 22% and 12% of formaldehyde use respectively, and C4 diols about 12%.)... 

Curing reactions of alicyclic polyamines with epoxy resins occur easily enough to allow carrying out at room temperatures. However, aromatic polyamines, acid anhydrides and phenol compounds usually need hardening accelerators, since their curing reactions require long times, even at elevated temperatures. Table 3 summarizes the general characteristics of these hardeners. 

Phenolphthalein is currently prepared by the reaction of phthalic anhydride with phenol in the presence of a strong acid. An ion exchange process, i.e. very similar to the present method for the manufacture of BPA from acetone and phenol, but at higher temperatures, has been reported. ... 

Phthalein reaction. Place in a dry test-tube about 0 2 g. of the phenol and an equal quantity of phthalic anhydride (or acid), moisten with 2 drops (not more) of cone. H2SO4 and gently fuse together for about 1 minute. Allow to cool somewhat, and then add 10% NaOH solution in excess. 

Other substituents which belong with this group have already been discussed. These include phenol, anisole and compounds related to it ( 5.3.4 the only kinetic data for anisole are for nitration at the encounter rate in sulphuric acid, and with acetyl nitrate in acetic anhydride see 2.5 and 5.3.3, respectively), and acetanilide ( 5.3.4). The cations PhSMe2+, PhSeMe2+, and PhaO+ have also been discussed ( 9.1.2). Amino groups are prevented from showing their character ( — 7 +717) in nitration because conditions enforce reaction through the protonated forms ( 9.1.2). 

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)... 

As shown in the sixth entry of Table 24 4 C acylation of phenols is observed under the customary conditions of the Friedel-Crafts reaction (treatment with an acyl chloride or acid anhydride m the presence of aluminum chloride) In the absence of aluminum chloride however O acylation occurs instead... 

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... 

On reaction with acyl chlorides and acid anhydrides phenols may undergo either acylation of the hydroxyl group (O acylation) or acylation of the ring (C acylation) The product of C acylation is more stable and predominates under conditions of thermodynamic control when alu mmum chloride is present (see entry 6 m Table 24 4 Section 24 8) O acylation is faster than C acylation and aryl esters are formed under conditions of kinetic control... 

Bisa.codyl, 4,4 -(2-PyridyLmethylene)bisphenol diacetate [603-50-9] (Dulcolax) (9) is a white to off-white crystalline powder ia which particles of 50 p.m dia predominate. It is very soluble ia water, freely soluble ia chloroform and alcohol, soluble ia methanol and ben2ene, and slightly soluble ia diethyl ether. Bisacodyl may be prepared from 2-pyridine-carboxaldehyde by condensation with phenol and the aid of a dehydrant such as sulfuric acid. The resulting 4,4 -(pyridyLmethylene)diphenol is esterified by treatment with acetic anhydride and anhydrous sodium acetate. Crystallisation is from ethanol. 

Uses ndReactions. The Prins reaction of 3-carene with formaldehyde in acetic acid gives mainly 2-carene-4-methanol acetate, which when saponified produces the 2-carene-4-methanol, both of which are commercial products of modest usage (60). 3-Carene (28) also reacts with acetic anhydride with a catalyst (ZnCl2) to give 4-acetyl-2-carene (29) (61), which is also a commercial product. Although 3-carene does not polymerize to produce terpene resins, copolymerization with phenol has been successfully commercialized by DRT in France (62). 

These can be prepared as for the benzoates using either acetic anhydride with 3N NaOH or acetyl chloride in pyridine. They are hydrolysed as described for the benzoates. This hydrolysis can also be carried out with aqueous 10% NaOH solution, completion of hydrolysis being indicated by the complete dissolution of the acetate in the aqueous alkaline solution. On steam distillation, acetic acid also distils off but in these cases the phenols (see above) are invariably solids which can be filtered off and recrystallised. 

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

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... 

The 1,3,4-oxadiazole 113 is formed from the azo compound 112 by the action of triphenylphosphine <96SL652>. A general synthesis of 1,3.4-oxadiazolines consists in boiling an acylhydrazone with an acid anhydride (e.g., Scheme 18) <95JHC1647>. 2-Alkoxy-2-amino-l,3,4-oxadiazolines are sources of alkoxy(amino)carbenes the spiro compound 114, for instance, decomposes in boiling benzene to nitrogen, acetone and the carbene 115, which was trapped as the phenyl ether 116 in the presence of phenol <96JA4214>. 

---