Phthalic anhydride, esterification

ASTM E 326-96, Standard Test Method for Hydroxyl Groups by Phthalic Anhydride Esterification, ASTM, Philadelphia, PA, 1996. 

American Society for Testing and Materials, Hydroxyl groups by phthalic anhydride esterification, E326-96. West Conshohocken, PA 19428. 

Chlorendic Acid. Chlorendic acid [115-28-6] and its anhydride [115-27-5] are widely used flame retardants. Chlorendic acid is synthesized by a Diels-Alder reaction of maleic anhydride and hexachlorocyclopentadiene (see CyclopentadlENE and dicyclopentadiente) in toluene followed by hydrolysis of the anhydride using aqueous base (60). The anhydride can be isolated directly from the reaction mixture or can be prepared in a very pure form by dehydration of the acid. The principal use of chlorendic anhydride and chlorendic acid has been in the manufacture of unsaturated polyester resins. Because the esterification rate of chlorendic anhydride is similar to that of phthalic anhydride, it can be used in place of phthalic anhydride in commercial polyester... 

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

Certain monobutyltin compounds have recently been introduced 561) as esterification catalysts, e.g., in the reaction of phthalic anhydride with octanol to produce dioctyl phthalate. 

Figure 27 shows that the release rate of CBP from the polymer decreased with increasing injection-molding temperatures. Samples with decreased levels of phthalic anhydride and increased levels of the phthalate half ester erode at slower rates presumably because the phthalic acid (pKai = 2.9 and pKa2 = 5.5) is a stronger acid than its alkyl half ester (estimated pKa = 3.6) and because the concentration of acidic groups is reduced by the esterification reaction. 

Di- -octylphthalate is produced commercially as a component of mixed phthalate esters, including straight-chain C6, C8, and CIO phthalates (EPA 1993a). Di- -octylphthalate is produced at atmospheric pressure or in a vacuum by heating an excess of w-octanol with phthalic anhydride in the presence of an esterification catalyst such as sulfuric acid or / -tolucncsul Tonic acid. The process may be either continuous or discontinuous (EPA 1993a HSDB 1995). Di- -octylphthalate can also be produced by the reaction of -octylbromide with phthalic anhydride. 

The pressure effect on the bimolecular rate constants for the esterification of phthalic anhydride with methanol in supercritical carbon dioxide (Ellington et al., 1994). 

Esterification Using Pyromellitic Dianbydri.de is described on pp 458—59. This method combines the advantages of esterification by acetic anhydride and by phthalic anhydride... 

Part A(1963)> VanNostrand, Princeton, NJ, pp 455—57 "General Methods Using Esterification with Acetic Anhydride 458 "Esterification Using Phthalic Anhydride 458—59 "Esterification Using Pyromellitic Dianhydride 459—61 "Determination of Compounds with Adjacent Hydroxyl Groups (Glycols) (See Ref 2)... 

During the appropriate tests phthalic anhydride was smoothly esterified with 2-ethylhexanol in the mole ratio 1 4. The reaction temperature rose to 200°C. after about 15 minutes, then rose slowly up to 210°C. till the end of the esterification. Table I shows the esterification time in hours after 99.9% conversion, while continuously removing the reaction water, according to the acid number relative to monooctyl phthalic acid. Furthermore, it indicates the ester colors according to the iodine scale in milligrams iodine/100 ml., whereby 1 mg. iodine/100 ml. can be more or less compared with a dye number of 120 APHA. Since, the values are obtained with the same starting materials, it is possible to compare the color numbers. They show that with the same times, the amphoteric catalysis achieves better colors than in the reaction course containing catalytically effective acids. 

Trimellitate Esters. These materials are produced by the esterification of a range of alcohols with trimellitic anhydride (TMA), which is similar in structure to phthalic anhydride with the exception of the third functionality (COOH) on the aromatic ring. Consequently, esters are produced in the ratio of three moles of alcohol to one mole of anhydride. Common esters in this family are tris-2-ethyhexyl trimellitate (trioctyl trimellitate, TOTM) L79TM, an ester of mixed semilinear C7 and C9 alcohols and L810TM, an ester of mixed linear Cg and C1Q alcohols. 

Emissions During Plasticizer Production and Distribution. Phthalate plasticizers are produced by esterification of phthalic anhydride in closed systems hence losses to atmosphere are minimal. Inquiries of all the principal plasticizer producers indicate a maximum total emission in Western Europe of 220 t/yr, 90% of which is to the water compartment. This level is expected to decrease in the future due to increasing plant water treatment. 

The properties of polymers formed by the step growth esterification (1) of glycols and dibasic acids can be manipulated widely by the choice of coreactant raw materials (Table 1) (2). The reactivity fundamental to the majority of commercial resins is derived from maleic anhydride [108-31-6] (MAN) as the unsaturated component in the polymer, and styrene as the coreactant monomer. Propylene glycol [57-55-6] (PG) is the principal glycol used in most compositions, and (o o)-phthalic anhydride (PA) is the principal dibasic acid incorporated to moderate the reactivity and performance of the final resins. 

Other large-volume eslers are vinyl acetate t VAM). inethyl methacrylate iMMA). and dioclyl phthalate (DOP). VAM is produced for the most part hy the vapor-phase oxidative acetoxylation of ethylene. MMA and DOP are produced by direct esterification techniques involving mcthacrylic acid and phthalic anhydride, respectively... 

The catalytic activity of H3PW12O40 for esterification of phthalic anhydride with 2-ethylhexanol is higher than those of conventional soluble acids such as / -toluenesulfonic acid (202). 

Esters of allyl alcohol, e.g., diallyl phthalate, are used as bifunctional polymerization monomers and can be prepared by simple esterification of phthalic anhydride with allyl alcohol. Several acrylic esters, such as ethyl or methyl acrylates, are also widely used and can be made from acrylic acid and the appropriate alcohol. The esters are more volatile than the corresponding acids. 

For the esterification of terephthalic acid with ethylene glycol at 473 K, SO /TiCh calcined at 773 K is much more active than SiC -A Ch as shown in Fig. 6 [60]. The SO /TiCh showed a maximum activity when calcined at 573 K for the esterification of oleic acid with glycerol and of propionic acid with butanol at 403 K [61], where the active sites were attributed to Bronsted acid sites from a correlation between the activity and the Bronsted acidity. The esterification of phthalic anhydride with 2-ethylhexanol to form dioctyl phthalate is also efficiently catalyzed by solid super-acids, the selectivity being more than 90% [62]. The... 

Degussa AG Di 2 ethyl hexyl phthalate (DOP) 2-Ethylhexanol, phthalic anhydride Catalytic esterification, low alpha number NA NA... 

P.J. Elwing B. Warskowsky, AnalChem 19, 1006(1947) (Detn of hydroxyl groups by esterification using phthalic anhydride)... 

Matsuda and Ueda [27] also extensively investigated the esterification of wood in order to make a totally thermoplastic material. They esterified wood with a solvent by simply heating wood meal with succinic anhydride for 3 h at temperatures greater than 60°C. The wood meal was readily molded at 180°C under a pressure of 570 kg/cm for 10 min. The moldability of various esterified woods decreased in the following anhydride order succinic anhydride > maleic anhydride > phthalic anhydride. 

Cobalt catalysts completely dominated industrial hydroformylation rmtil the early 1970s, when rhodium catalysts were commercialized. Most aldehydes produced are hydrogenated to alcohols or oxidized to carboxylic acids. Esterification of the alcohols with phthalic anhydride produces dialkyl phtha-late plasticizers that are primarily used for polyvinyl chloride plastics - the largest single end-use. Detergents and surfactants make up the next largest category, followed by solvents, lubricants, and chemical intermediates. 

Dialkyltin dicarboxylates, e g. Bu2Sn(02CCu 1123)2, are useful catalysts for polyurethane foam formation and as cross-linking agents for room-temperature vulcanization. Monobutyltins have been used as catalysts in transesterification and esterification reactions, e.g. in the reaction between phthalic anhydride and 2-ethylhexanol. 

Fatty alcohol can be fractionated to separate the C8-C10 fraction, known as plasticizer range alcohol, and the C12-C18, known as the detergent range alcohol. The plasticizer range alcohol is a liquid with good dissolving power. It can be used in a limited way as a solvent for printing inks and lacquers. Esterification with a polycarboxylic acid, such as phthalic anhydride, yields an excellent plasticizer especially for PVC. 

---