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Low-temperature oxidation of bitumen with air in the temperature range of 130–160 °C was investigated. Of particular interest were the addition reactions taking place during oxidation, which contributed to the observed increase in viscosity of oxidized bitumen. During the autoxidation of bitumen, the relative aliphatic to aromatic loss-ratio of hydrogen increased from 18:1 to 30:1 when the temperature was increased from 140 °C to 150 °C and then remained almost the same at 160 °C. It coincided with a bitumen oxidation selectivity change reported in the literature. The hydrocarbon class responsible for most addition reactions during bitumen oxidation is the naphthenic-aromatic class. A model compound oxidation study at 130 °C found no addition products during paraffin oxidation, low addition product selectivity for naphthenic and alkylaromatic compounds, and no measurable oxidation of aromatics without alkyl groups. It was proposed that the dominant pathway for addition reactions of hydrocarbons is hydroge...

This paper examines the most important factors that affect the functionalization of light alkanes by means of selective oxidation. The state-of-the-art in paraffin oxidation and the main features that affect the choice of the reactor and the process configuration are discussed.

The sections in this article are Introduction Analyzing the Challenge of Heterogeneously Catalyzed Alkane Oxidation Analysis on a Microscopic Basis of the Critical Steps of Paraffin Oxidation Utilizing Solid Catalysts Utilizing Solid Catalysts Activation of Oxygen and Paraffin Models for the Active Site The Role of Co-Feeds in the Educt Stream The Role of the Crystalline Nature and the Admixture of Different Crystalline Phases for the Catalyst The Role of the Acid–Base Interaction of Reactant and Catalyst Analysis of the Technical Challenges of Paraffin Oxidation Utilizing Solid Catalysts Conversion of Butane to Maleic Anhydride: An Overview of a Mature Technology Manufacturing Technologies for MA from n-Butane The VPO-Catalyst: Structural Basis and Synthetic Pathways The VPO-Catalyst: Reaction Pathways and Potential Active Sites of the Catalyst Propane Oxidation to Acrylic Acid and Acrylonitrile: Getting Closer to a Technical Solution Rutile-Based Structures for Selective Propane Oxidation Complex Bronze Structures Based on Molybdenum for Selective Propane Oxidation Ethane to Acetic Acid: The Search for a Viable Pathway Outlook Acknowledgments Keywords: oxyfunctionalization; solid catalyst; maleic anhydride

1. A method has been worked out for preparing return raw material for the oxidation process, consisting of treating the unsaponifiables with a water solution of the low-molecular organic acids which is obtained in the form of an aqueous condensate in the manufacture of synthetic fatty acids, with separation of the salt solution in an electrical field. 2. The use of a dc electrical field reduces the settling time for unsaponifiables 10- to 12-fold and improves the completeness of separation of sodium salts from unsaponifiables. 3. The use of return raw material which has been treated with acid water makes it possible to stabilize the oxidation process, reduce the oxidation time by a minimum of 30%, and reduce the air consumption by at least a factor of 1.4.

The induction of paraffin oxidation in intact cells of Pseudomonas aeruginosa was investigated. Oxidation of 14 C-heptane by cell-free extracts of adapted cells showed that the activity of whole cells is a reliable reflection of the synthesis of the first enzyme in the degradation of n -alkanes. Induction was significantly affected by glucose and could be completely repressed by malate. The amino acids l -proline, l -alanine, l -arginine, and l -tyrosine exhibited a rather low repressor action. Malonate, a nonrepressive carbon source, allowed gratuitous enzyme synthesis. A number of compounds which did not sustain growth were found to be suitable substitutes for paraffins as an inducer. Among these were cyclopropane and diethoxymethane. The induction studied under conditions of gratuity with the latter compound as an inducer showed immediate linear kinetics only at saturating inducer concentrations. With n -hexane as the inducer, a lag time was always observed, even when high concentrations were used.