B.K. Hodnett

Vanadium-phosphorus Oxide Catalysts for the Selective Oxidation of C-4 Hydrocarbons To Maleic-anhydride

Maleic anhydride (MA) is an important intermediate in a large number of chemtcal processes. World capacity is of the order of 700,000 tonnes/yr, and its major use is in the manufacture of unstaurated polyester resins, which accounts for 60–70% of production [1,2]. Other uses are summarized in Table 1

THE ROLE OF REACTANT AND PRODUCT BOND ENERGIES IN DETERMINING LIMITATIONS TO SELECTIVE CATALYTIC OXIDATIONS

Abstract A wide range of selective oxidation reactions occurring in the gas phase over oxide catalysts have been surveyed. The reactions include oxidative dehydrogenation of alkanes, oxidation of alkenes and alcohols to aldehydes and the oxidation of alkanes to acids. The literature data was gathered into a series of selectivity-conversion plots and each plot was constructed with data from a variety of catalysts and a range of operating conditions. There was a clear upper limit in terms of selectivity-conversion beyond which experimental studies have not advanced for each reaction studied. The object of this study is to elucidate the reasons for the observed limitations. A correlation was observed between the limiting selectivities at fixed conversions and the function: D 0 H C H (reactant) - D 0 H C H or C C (product) where D 0 H C H (reactant) is the bond dissociation enthalpy of the weakest C H bond in the reactant and D 0 H C H or C C (product) is the bond dissociation enthalpy of the weakest bond in the selective oxidation product. The results show that if this difference is less than 30kJ/mol a very high selectivity is achievable at all conversions, whereas for differences greater than 70 kJ/mol poor selectivity is always recorded. This finding characterizes the degree to which active sites in oxide catalysts are capable of selectively activating target bonds.

The catalytic oxidation of ammonia : influence of water and sulfur on selectivity to nitrogen over promoted copper oxide/alumina catalysts

Abstract The CuO/Al2O3 system is active for ammonia oxidation to nitrogen and water. The principal by-products are nitrous oxide and nitric oxide. Nitrous oxide levels increase with the addition of various metal oxides to the basic copper oxide/alumina system. Addition of sulfur dioxide to the reaction stream sharply reduces the level of ammonia conversion, but has a beneficial effect on selectivity to nitrogen. Added water vapour has a lesser effect on activity but is equally beneficial in terms of selectivity to nitrogen. The CuO/Al2O3 is also active for the selective catalytic reduction of nitric oxide by ammonia, but this reaction is not effected by sulfur dioxide addition. A mechanism for ammonia oxidation to nitrogen is proposed wherein part of the ammonia fed to the catalyst is converted into nitric oxide. A pool of monoatomic surface nitrogen species of varying oxidation states is established. N2 or N2O are formed depending upon the average oxidation state of this pool. An abundance of labile lattice oxygen species on the catalyst surface leads to overoxidation and to N2O formation. On the other hand, reduced lability of surface lattice oxygen species favours a lower average oxidation state for the monoatomic surface nitrogen pool and leads to N2 formation.

Adsorption and Activity of Proteins onto Mesoporous Silica

The adsorption and activity of cytochrome c onto two different MCM-41 materials, MCM-41/28 and MCM-41/45 with average pore diameters of 28 and 45 Å respectively, is presented. Nitrogen gas adsorption/desorption isotherms before and after protein adsorption, and peroxidative activity profiles of the adsorbed protein demonstrate that the protein is adsorbed into the mesoporosity and remains active. The adsorption of a range of different proteins onto both MCM-41/28 and 45 shows how protein properties affect adsorption.

Influence of boria loading on the acidity of B2O3/Al2O3 catalysts for the conversion of cyclohexanone oxime to caprolactam

Abstract Boron oxide catalysts supported on alumina have been prepared with boria loadings in the range 0–20 wt.-%. These materials were characterized by B.E.T. surface area measurements, X-ray diffraction and temperature-programmed desorption of ammonia and were used as catalysts for the Beckmann rearrangement of cyclohexanone oxime to caprolactam by passing the oxime vapour through a reactor containing the catalysts at 300°C. The surface areas of the samples decreased as the boria loading was increased, and all catalysts tested for the rearrangement reaction diminished in activity with time-onstream. There was a direct relationship between the amount of coke which formed on the surface and the loss in catalytic activity. This loss was least for the highest boron oxide loading tested, and this catalyst also featured the least amount of coke formation. Selectivity to caprolactam was associated with the presence of surface acidic sites of intermediate strength. A correlation was observed between the concentration of these surface sites and the selectivity to caprolactam.

Achieving Continuous Manufacturing: Technologies and Approaches for Synthesis, Workup, and Isolation of Drug Substance. May 20–21, 2014 Continuous Manufacturing Symposium

This whitepaper highlights current challenges and opportunities associated with continuous synthesis, workup, and crystallization of active pharmaceutical ingredients (drug substances). We describe the technologies and requirements at each stage and emphasize the different considerations for developing continuous processes compared with batch. In addition to the specific sequence of operations required to deliver the necessary chemical and physical transformations for continuous drug substance manufacture, consideration is also given to how adoption of continuous technologies may impact different manufacturing stages in development from discovery, process development, through scale-up and into full scale production. The impact of continuous manufacture on drug substance quality and the associated challenges for control and for process safety are also emphasized. In addition to the technology and operational considerations necessary for the adoption of continuous manufacturing (CM), this whitepaper also addresses the cultural, as well as skills and training, challenges that will need to be met by support from organizations in order to accommodate the new work flows. Specific action items for industry leaders are.This whitepaper highlights current challenges and opportunities associated with continuous synthesis, workup, and crystallization of active pharmaceutical ingredients (drug substances). We describe the technologies and requirements at each stage and emphasize the different considerations for developing continuous processes compared with batch. In addition to the specific sequence of operations required to deliver the necessary chemical and physical transformations for continuous drug substance manufacture, consideration is also given to how adoption of continuous technologies may impact different manufacturing stages in development from discovery, process development, through scale-up and into full scale production. The impact of continuous manufacture on drug substance quality and the associated challenges for control and for process safety are also emphasized. In addition to the technology and operational considerations necessary for the adoption of continuous manufacturing (CM), this whitepaper also addresses the cultural, as well as skills and training, challenges that will need to be met by support from organizations in order to accommodate the new work flows. Specific action items for industry leaders are: Develop flow chemistry toolboxes, exploiting the advantages of flow processing and including highly selective chemistries that allow use of simple and effective continuous workup technologies. Availability of modular or plug and play type equipment especially for workup to assist in straightforward deployment in the laboratory. As with learning from other industries, standardization is highly desirable and will require cooperation across industry and academia to develop and implement. Implement and exploit process analytical technologies (PAT) for real-time dynamic control of continuous processes. Develop modeling and simulation techniques to support continuous process development and control. Progress is required in multiphase systems such as crystallization. Involve all parts of the organization from discovery, research and development, and manufacturing in the implementation of CM. Engage with academia to develop the training provision to support the skills base for CM, particularly in flow chemistry, physical chemistry, and chemical engineering skills at the chemistry-process interface. Promote and encourage publication and dissemination of examples of CM across the sector to demonstrate capability, engage with regulatory comment, and establish benchmarks for performance and highlight challenges. Develop the economic case for CM of drug substance. This will involve various stakeholders at project and business level, however establishing the critical economic drivers is critical to driving the transformation in manufacturing.

Factors affecting selectivity in the rearrangement of cyclohexanone oxime to caprolactam over modified aluminas

Abstract The Beckmann rearrangement of cyclohexanone oxime to caprolactam has been studied over a range of aluminas modified by the addition of chloride, phosphate, sulphate, sodium or boron oxide. The catalysts were characterized by temperature-programmed desorption of ammonia and carbon dioxide and by pyridine adsorption monitored by infrared spectroscopy. Conversion of the oxime declined with time-on-stream for all catalysts studied, but selectivity to caprolactam remained constant during the first five hours of operation. In this period a relationship was observed between the selectivity to cap- rolactam and the surface concentration of intermediate strength acid sites, wherein the selectivity increased as the surface concentration of these sites increased. The boron oxide modified alumina presented the largest concentration of intermediate strength acid sites, and the low level of coke formation on this material was associated with the total absence of surface basicity. A mechanism for the rear- rangement reaction on the modified aluminas is presented.

Adsorption and activity of cytochrome c on mesoporous silicates

Cytochrome c (horse heart) has been adsorbed onto a range of mesoporous silicate materials with the extent of adsorption dependent on the silicate pore size; adsorption and activity profiles of the adsorbed protein are reported.

A comparative study of the use of powder X-ray diffraction, Raman and near infrared spectroscopy for quantification of binary polymorphic mixtures of piracetam

Diffraction and spectroscopic methods were evaluated for quantitative analysis of binary powder mixtures of FII(6.403) and FIII(6.525) piracetam. The two polymorphs of piracetam could be distinguished using powder X-ray diffraction (PXRD), Raman and near-infrared (NIR) spectroscopy. The results demonstrated that Raman and NIR spectroscopy are most suitable for quantitative analysis of this polymorphic mixture. When the spectra are treated with the combination of multiplicative scatter correction (MSC) and second derivative data pretreatments, the partial least squared (PLS) regression model gave a root mean square error of calibration (RMSEC) of 0.94 and 0.99%, respectively. FIII(6.525) demonstrated some preferred orientation in PXRD analysis, making PXRD the least preferred method of quantification.

Simultaneous removal of SO2/NOx from flue gases. Sorbent/catalyst design and performances

Abstract The kinetic and mechanistic aspects of the interaction of SO 2 with supported copper-based sorbent/catalysts, of the regeneration of the sorbent/catalyst by reductive treatment and of the interaction of the sulfated sorbent/catalyst with ammonia and NO x to form N 2 are discussed with reference to sorbent/catalyst and reactor design for efficient simultaneous removal of SO 2 /NO x from flue gases in a single stage reactor.