Mechanistic Insight Into the Application of Alumina-Supported Pd Catalysts for the Hydrogenation of Nitrobenzene to Aniline.

Two Pd/γ-AlO catalysts are examined for the vapor phase hydrogenation of nitrobenzene over the temperature range of 60-200 °C. A 1 wt % catalyst is selected as a reference material that is diluted with γ-alumina to produce a 0.3 wt % sample, which is representative of a metal loading linked to a candidate industrial specification aniline synthesis catalyst.

Toward High Selectivity Aniline Synthesis Catalysis at Elevated Temperatures.

In connection with an initiative to enhance heat recovery from the large-scale operation of a heterogeneously catalyzed nitrobenzene hydrogenation process to produce aniline, it is necessary to operate the process at elevated temperatures (>100 °C), a condition that can compromise aniline selectivity. Alumina-supported palladium catalysts are selected as candidate materials that can provide sustained aniline yields at elevated temperatures. Two Pd/AlO catalysts are examined that possess comparable mean Pd particle sizes (∼5 nm) for different Pd loading: 5 wt % Pd/AlO and 0.

Phosgene Synthesis Catalysis: The Influence of Small Quantities of Bromine in the Chlorine Feedstream.

The effect of relatively low concentrations of Br in the Cl feedstock for phosgene synthesis catalysis via the reaction of CO and Cl over activated carbon (Donau Supersorbon K40) is explored. Under the stated reaction conditions and in the absence of a catalyst, BrCl forms from the reaction of Cl and Br. Phosgene synthesis over the catalyst at 323 K is investigated for Br:Cl molar flow ratios in the range 0-1.

A structural and spectroscopic investigation of the hydrochlorination of 4,4'-methylenedianiline.

The hydrochlorination of 4,4'-methylenedianiline, NH(2)C(6)H(4)CH(2)C(6)H(4)NH(2) (MDA), in chlorobenzene to produce 4,4'-methylenedianiline dihydrochloride, [H(3)NC(6)H(4)CH(2)C(6)H(4)NH(3)]Cl(2) (MDA x 2 HCl) is an important reaction for the production of isocyanates, which are used to manufacture polyurethanes. This reaction is examined here. MDA is moderately soluble in chlorobenzene, whereas MDA x 2 HCl is effectively insoluble.

A structural and spectroscopic investigation of the hydrochlorination of 4-benzylaniline: the interaction of anhydrous hydrogen chloride with chlorobenzene.

The hydrochlorination of 4-benzylaniline in chlorobenzene to produce 4-benzylaniline hydrochloride has been examined. This has required spectroscopic and computational analysis of the solvation of gaseous HCl in the process solvent. The characterisation of the reagent and product of the hydrochlorination reaction by various techniques, including FTIR and (1)H NMR spectroscopy and X-ray diffraction, is described.