SUBJECTS maleic acid

Continuous process. An aq. soln. of maleic acid subjected to countercurrent contact with xylene vapors on a column filled with Raschig rings at a bottom temp, of 136-142° and a top temp, of 92° maleic anhydride. Y 92-9 J. Kubica et al., Przemysl Ghem. 41, 458 (1962). 

The diacids are characterized by two carboxyHc acid groups attached to a linear or branched hydrocarbon chain. AUphatic, linear dicarboxyhc acids of the general formula HOOC(CH2) COOH, and branched dicarboxyhc acids are the subject of this article. The more common aUphatic diacids (oxaUc, malonic, succinic, and adipic) as weU as the common unsaturated diacids (maleic acid, fumaric acid), the dimer acids (qv), and the aromatic diacids (phthaUc acids) are not discussed here (see Adipic acid Maleic anhydride, maleic acid, and fumaric acid Malonic acid and derivatives Oxalic acid Phthalic acid and OTHERBENZENE-POLYCARBOXYLIC ACIDS SucciNic ACID AND SUCCINIC ANHYDRIDE). The bihinctionahty of the diacids makes them versatile materials, ideally suited for a variety of condensation polymerization reactions. Several diacids are commercially important chemicals that are produced in multimillion kg quantities and find appHcation in a myriad of uses. 

Ozonization of phenol in water resulted in the formation of many oxidation products. The identified products in the order of degradation are catechol, hydroquinone, o-quinone, cis,ds-muconic acid, maleic (or fumaric) and oxalic acids (Eisenhauer, 1968). In addition, glyoxylic, formic, and acetic acids also were reported as ozonization products prior to oxidation to carbon dioxide (Kuo et al, 1977). Ozonation of an aqueous solution of phenol subjected to UV light (120-W low pressure mercury lamp) gave glyoxal, glyoxylic, oxalic, and formic acids as major products. Minor products included catechol, hydroquinone, muconic, fumaric, and maleic acids (Takahashi, 1990). Wet oxidation of phenol at 320 °C yielded formic and acetic acids (Randall and Knopp, 1980). 

SMANCS (Styrere-co-maleic acid/anhydride polymer bound to neocarzinostatin Neocarzinostatin (an antitumor protein) Amide bond between polymer carboxyl and protein amino None N/A SMANCS showed anticancer activity against many tumor cell lines, and had lower IC50 values than five other anticancer agents tested Liver tumors reduced more than 50% after 6 months in human subjects 15, 56, 57... 

Other studies on the influence of tablet excipients on dmg decomposition have identified problems with stearate salts and it has been suggested that these salts should be avoided as tablet lubricants if the active component is subject to hydroxide-ion-catalysed degradation. The degradative effect of the alkali stearates is inhibited in the presence of malic, hexamic or maleic acids owing, it is thought, to competition for the lubricant cation between the dmg and the additive acid. 

Separation into two phases may occur not only in solids but also in solution. This has been observed in copolymers of maleic acid with alkyl vinyl ethers by U. P. Strauss and P. Lane. The microstructure of two-phase poly (methyl methacrylate) is the subject of D. T. Turner and R. P. Kusy. 

The subject of surfactant-modified, water-soluble polymers, briefly discussed in Water-Soluble Polymers, is addressed in the last three sections (Chapters 16-28) of this book. These associative thickeners are covered in detail, ranging from the maleic acid copolymers of variable compositions introduced in various commercial markets in the early 1960s to the most recent entries (that is, in the open literature), hydrophobe-modified poly (acrylamide). Chapter 23 is complementary to the spectroscopic studies in Chapters 13-15 it explores new approaches to understanding associations in aqueous media. The three hydrophobe-modified polymers that have gained commercial acceptance in the 1980s, (hydroxyethyl)cellulose, eth-oxylate urethanes, and alkali-swellable emulsions, are discussed in detail. In particular, hydrophobe-modified (hydroxyethyl)cellulose, which is... 

Other methods that have been reported include inducing the cyclization reaction by incorporating thioamide groups [491], copolymerized AF-vinylpyrrolidone [492], or vinyl halogen monomers in copolymerized or grafted form [493]. Stabilizers based on maleic acid are also effective [494,495]. Reviews on the subject have been published by Brown [496] and Krcma [497]. 

Alternately, when a mixture of fumaric acid, water, and chlorine are subjected to sunlight for 4 days, a quantitative yield of the meso dichlorosuc-cinic acid 57 is obtained/ Maleic acid on the other hand gives racemic (dl) acid 58. Thus, under these reaction conditions, trans addition is said to occur. However, if chlorine is added to soluble neutral salts of the acids in water in the presence of excess chloride ion, cis addition occurs. 

Addition of bromine has been the subject of a number of studies. When a neutral salt of maleic or fumaric acid (A = COO ) is brominated in water, the meso derivative is the predominant product. Bell and Pring also report that the meso product is obtained on bromination of the diethyl esters of fumaric and maleic acids. Terry and Eicheberger observed 78% meso product from disodium maleate, a cis addition product which is unexpected. The prevalent bromonium ion mechanism proposed by Roberts and Kim-ball could easily explain the trans addition as follows ... 

Corrosion inhibiting compositions for metals subjected to highly acidic environments may be produced by reacting in a condensation reaction a styrene/ maleic anhydride copolymer with a polyamine to produce a polyimidoamine inhibitor [1568]. These inhibitors exhibit film-forming and film-persistency characteristics. Some relevant polyamines are listed in Table 6-2. 

Noteworthy among the few reports in the literature on this subject is the work of Andersen, Bills, Mishuck, Moe and Schultz [3] on the mechanism of combustion of a mixture of 75% NH4C104 and 25% polyester with styrene. The work of Gro-dzinski [18] who investigated the thermal decomposition of the mixtures of various combustible substances with potassium perchlorate in a ratio of 20/80 by weight, is also of great interest. The combustible ingredients include asphalt and polyester resin from unsaturated (maleic) or saturated acids. 

A new stereoselective synthesis of 1,2,3-trisubstituted cyclopentanes based on the Wag-ner-Meerwein rearrangement of a 7-oxabicyclo[2.2.1]heptyl 2-cation starts with the Diels-Alder product of maleic anhydride and a furan (78TL2165, 79TL1691). The cycloadduct was hydrogenated and subjected to methanolysis. The half acid ester (47) was then electrolyzed at 0 °C to generate a cationic intermediate via the abnormal Kolbe reaction (Hofer-Moest reaction). Work-up under the usual conditions provided the 2-oxabicyclo[2.2.1]heptane (48) in 83% yield. Treatment of this compound in turn with perchloric acid effected hydrolysis of the ketal with formation of the trisubstituted cyclopentane (49) in nearly quantitative yield (Scheme 11). Cyclopentanes available from this route constitute useful... 

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