Maleic anhydride . See

Since anhydrides are much more reactive than carboxylic acids, reaction kinetics is controlled by the second step. The scope and apphcations of this reaction are the same as direct polyesterification but are practically limited to the synthesis of unsaturated polyesters and alkyd resins from phtliahc and maleic anhydrides (see Sections 2.4.2.1 and 2.4.23). 

For a review of Diels-Alder reactions with maleic anhydride see Kloetzel, M.C. Org. React., 1948, 4, 1. 

C4 Alkenes. Several industrial processes have been developed for olefin production through catalytic dehydrogenation138 166 167 of C4 alkenes. All four butenes are valuable industrial intermediates used mostly for octane enhancement. Isobutylene, the most important isomer, and its dimer are used to alkylate isobutane to produce polymer and alkylate gasoline (see Section 5.5.1). Other important utilizations include oxidation to manufacture maleic anhydride (see Section 9.5.4) and hydroformylation (see Section 7.1.3). 

Oxidation of butane and butenes to maleic anhydride is discussed in connection with the synthesis of maleic anhydride (see Section 9.5.4.). 

Dipolar cycloadditions lead to six-membered rings. Rearrangements may be encountered. Thiazole or 2-methylthiazole (129 R = H and Me) with DMAD forms an initial 1,4-dipolar species (130). Reaction of (130) with a second DMAD gives a 1 2 adduct, presumably (131). Ring opening to (132), followed by cyclization in the alternative mode, resulted in (133) (78AHC(23)263) (see also CHEC 4.19). For the similar reactions of pyridine with DMAD and pyridazine with maleic anhydride see Section 3.2.1.3.7. 

Two carboxylic acid groups can combine by condensing out a water molecule to form an acid anhydride. Draw the structures of (a) acetic anhydride, which involves two molecules, and (b) maleic anhydride (see Problem 15.21), in which only one molecule is involved. 

Analytical pyrolysis of certain polymers and copolymers do not provide too much relevant information because of the rapid decomposition of the groups specific to that polymer. For example, the copolymers with maleic anhydride (see e.g. Sections 5.1 and 5.9) generate mainly CO2 from the maleic anhydride units. For the identification and for other studies on these types of polymers or copolymers, a polymer derivatization prior to pyrolysis can be applied [71]. For example, poly(allylamine) can be derivatized with acetonylacetone in a water solution by adding a NaOH. The reaction leads to the formation of poly(N-allyl-2,5-dimethylpyrrole) as shown below ... 

The pyrogram of this copolymer is almost identical to that of isotactic polypropylene, and no trace of the graft units were seen in the pyrolysate. The same results were obtained for the pyrolysis of poly(ethylene-gra/f-maleic anhydride) 3% wt. maleic anhydride (see Figure 6.1.14). The graft units cannot be detected for this polymer, using Py-GC/MS. 

The comparison of the pyrogram of polyisoprene-gra/f-maleic anhydride with that of polyisoprene shows no significant difference. Neither 2,5-furandione nor dihydro-2,5-furandione were detected in the pyrogram of polyisoprene-graff-maleic anhydride. The same absence was noticed for other graft copolymers of maleic anhydride, such as for poly(ethylene-graff-maleic anhydride) (see Section 6.1). 

Captan (72), an example of the N-trichloromethanesulfenyl fungicides, is a useful protective foliar fungicide and seed dressing. It is prepared from butadiene and maleic anhydride (see Chapter 9, p. 151). The fungicidal activity arises from interaction with cellular thiols to give thiophosgene, which is probably the ultimate toxicant (Scheme 15). 

Maleic anhydride See furan-2,5-dione in Heterocyclic Compounds , Chapter 4. 

Cycloadditions. A cyclic movement of electrons can be drawn for any number of cycloadditions, but not all of them take place. Thus butadiene undergoes a Diels-Alder reaction with maleic anhydride (see p. 253), but ethylene and maleic anhydride do not give the cyclobutane 6.25 when they are heated together. 

Polymethyltetradecylsiloxane. See Polytetradecylmethylsiloxane Poly (methylvinyl ether). See Polyvinyl methyl ether Poly (methyl vinyl ether-alt-maleic anhydride) Poly(methyl vinyl ether/ maleic anhydride). See PVM/MA copolymer... 

Slyrene-ethylene/butylene-styrene block copolymer Poly (styrene-co-allyl alcohol). See Styrene/allyl alcohol copolymer Poly (styrene-co-butadiene). See Styrene/butadiene polymer Poly (styrene-co-maleic anhydride). See Styrene/MA copolymer Polystyrene latex Polystyrene resin. See Polystyrene Polystyrene, sulfonated. See Sodium polystyrene sulfonate... 

Polyvinyl methyl ether-maleic anhydride. See PVM/MA copolymer... 

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