Abstract

oxidation processes: The paper reviews the following vapor-phase

  1. Production of phthalic anhydride from naphtha-

  2. Production of maleic anhydride and fumaric acid

  3. Production of pyromellitic dianhydride from

  4. Production of naphthalic anhydride from acena- Modern industrial processes are briefly described.

The economic aspects, raw materials to be used and the future development of raw materials to be used for the above mentioned processes are critically reviewed.

The by-products, their economic utilization and their removal in post-installed purification units are discussed.

Finally, a forecast of future development is made. lene and orthoxylene; from benzene; durene and 1, 2,4, 5-alkyl benzenes; phthene.

Résumé

phase gazeuse: L'auteur étudie les procédés suivants d'oxydation en

  1. Fabrication d'anhydride phtalique à partir de naphtaline et d'orthoxylène;

  2. Fabrication d'anhydride maléique et d'acide fumarique à partir de benzène;

  3. Fabrication d'anhydride pyromellitique à partir de durène et de benzènes d'alcoyles 1,2,4, 5;

  4. Fabrication d'anhydride naphthalique à partir acénaphtène.

Après une description succincte des procédés de fabrication industrielle, l'auteur donne un aperçu critique sur leur rentabilité, les matières premières utilisées et l'évolution future de ces dernières.

En outre, il traite des sous-produits obtenus, de leur élimination dans des unités d'épuration ultérieures.

En conclusion, l'auteur donne un pronostic pour l'avenir.

INTRODUCTION

In the last twenty years or so carboxylic acids with two and more carboxylic groups, particularly their anhydrides, have become extremely important for the production of plasticizers, synthetic resins, polyesters, synthetic lubricants, insecticides and many other products. In 1966, for example, the production of phthalic anhydride will reach I million tons a year or even exceed this figure. In addition to acetic acid and its anhydride (approx. 1.6 MM tons per year) and terephthalic acid and its methyl ester (approx. 750 M tons per year) phthalic anhydride is, thus, the most important synthetic organic acid for the chemical industry and the yearly rate of increase is estimated at 7 per cent at least.

Another important dicarboxylic acid which is likewise obtained as anhydride on an industrial scale is maleic acid with a world production estimated at 150,000 tons in 1966. These two dicarboxylic acids are manufactured in almost all industrial countries. There by G. W. IBING, RUHROL. Bottrop, West Germany. are probably 100 phthalic anhydride plants and 45 maleic anhydride plants in operation.

The subject matter of this paper is polycarboxylic acids and their anhydrides which can be manufactured by economic processes t

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