INES – An Interface Between Experiments and Simulation to Support the Development of Robust Process Designs

The development of chemical processes is based on both experiments and process simulations. Data evaluation and reconciliation, model development and validation, and design of experiments are essential steps in this procedure. The different tools and approaches available are usually not supported in an integrated way in the process developer's workflow. Therefore, a framework for process design was created and integrated in a tool box which supports process design comprehensively. It contains methods for data selection and reconciliation, sensitivity analysis, model validation and model adjustment.     

Synthesis and flammability testing of epoxy functionalized phosphorous‐based flame retardants

Several potential new phosphorus‐containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3‐propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing via PCFC showed that the heat release reduction potential of each of the flame retardants was structure dependent, with phosphates tending to show more effectiveness than phosphonates in this study, and alkyl functionalized phosphorus groups (phosphate or phosphonate) being more effective at heat release reduction than cyclic functionalized groups. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42296.     

Introducing copper ions into zeolite Y by the thallous ion exchange method: single crystal structure of |Cu21.6Tl39.2|[Si121Al71O384]–FAU

The thallous ion exchange (TIE) method was used for the first time in an attempt to introduce copper ions into zeolite Y (FAU, Si/Al = 1.69). |Cu _10.9 ⁺ Cu _10.7 ²⁺ Tl _39.2 ⁺ |[Si₁₂₁Al₇₁O₃₈₄]–FAU was prepared by reacting fully dehydrated and fully Tl⁺-exchanged zeolite Y (Tl₇₁–Y) with CuCl₂(g) and its decomposition products CuCl(g) and Cl₂(g) at 673 K under anhydrous conditions. Its structure was determined using single-crystal crystallography with synchrotron X-radiation and was refined in the space group ${Fd}\bar{3}$ m (a = 24.769(1) Å) with all 903 unique data; the final error index, R ₁ = 0.075, was calculated using only the 858 reflections with F _o > 4σ(F _o). About 45 % of the Tl⁺ ions were replaced by 21.6 copper ions per unit cell at the following sites (distances to nearest framework oxygen atoms are given): 10.7 Cu²⁺ at site I′ in the sodalite cavity opposite double 6-rings (Cu²⁺–O = 2.093(9) Å), 3.5 Cu⁺ at site II opposite single 6-rings in the supercage (Cu⁺–O = 2.24(3) Å), and 7.4 Cu⁺ at site III near 12-rings in the supercage (Cu⁺–O = 2.45(7) Å). All Cu⁺ ions are in supercages where they are easily accessible to guest molecules. The remaining ca. 39 Tl⁺ ions per unit cell occupy three distinct positions: 12 are at a second site I′ (Tl⁺–O = 2.571(9) Å), 23 are at a second site II (Tl⁺–O = 2.732(10) Å), and 4 are at site III′ (Tl⁺–O = 2.871(16) Å) near triple 4-rings in the supercages.     

Hydrogenation of Cinnamaldehyde over Pd/Al2O3 Catalysts Modified with Thiol Monolayers

Modification of supported Pt catalysts with thiols has recently been shown to improve the hydrogenation selectivity of α,β-unsaturated aldehydes to unsaturated alcohols. Here, we apply a variety of organic thiol coatings to Pd/Al₂O₃ catalysts that typically have a much lower intrinsic selectivity for desired product formation. Thiol monolayers were found to increase hydrogenation selectivity to cinnamyl alcohol; however, unlike with Pt catalysts, the increase was independent of the identity of the organic tail.

     

Chlorine photolysis and subsequent OH radical production during UV treatment of chlorinated water

The photodegradation of chlorine-based disinfectants NH(2)Cl, HOCl, and OCl(-) under UV irradiation from low- (LP) and medium-pressure (MP) Hg lamps was studied. The quantum yields of aqueous chlorine and chloramine under 254nm (LP UV) irradiation were greater than 1.2molEs(-1) for free chlorine in the pH range of 4-10 and 0.4molEs(-1) for monochloramine at pH 9. Quantum yields for MP (200-350nm) ranged from 1.2 to 1.7molEs(-1) at neutral and basic pH to 3.7molEs(-1) at pH 4 for free chlorine, and 0.8molEs(-1) for monochloramine. Degradation of free chlorine was enhanced under acidic water conditions, but water quality negatively impacted the MP Hg lamp degradation of free chlorine, compared to the LP UV source. The production of hydroxyl radical via chlorine photolysis was assessed along with the rate of reaction between ()OH and HOCl using radical scavengers (parachlorobenzoic acid and nitrobenzene) in chlorinated solutions at pH 4. The quantum yield of OH radical production from HOCl at 254nm was found to be 1.4molEs(-1), while the reaction of HOCl with OH radical was measured as 8.5x10(4)M(-1)s(-1). NH(2)Cl was relatively stable in all irradiated solutions, with <0.3mgL(-1) increase in nitrate following a UV dose of 1000mJcm(-2). For water treatment plants, no significant changes in chlorine concentration would be expected under typical pH levels and UV doses; however, the formation of ()OH could have implications for chlorinated byproducts or decay of unwanted chemical contaminants.     

Synthesis and catalysis

Research projects of the Department of Chemistry, University of Basel are reviewed ranging from the synthesis of complex natural products to the development of metalorganic catalysts and organocatalysts.     

Rheological evaluation of the isothermal cure characteristics of medical grade silicone elastomers

Silicone elastomer systems have been shown to offer potential for the fabrication of medical devices and sustained release drug delivery devices comprising low molecular weight drugs and protein therapeutics. For drug delivery systems in particular, there is often no clear rationale for selection of the silicone elastomer grade, particularly in respect of optimizing the manufacturing conditions to ensure thermal stability of the active agent and short cycle times. In this study, the cure characteristics of a range of addition‐cure and condensation‐cure, low‐consistency, implant‐grade silicone elastomers, either as supplied or loaded with the model protein bovine serum albumin (BSA) and the model hydrophilic excipient glycine, were investigated using oscillatory rheology with a view to better understanding the isothermal cure characteristics. The results demonstrate the influence of elastomer type, cure temperature, protein loading, and glycine loading on isothermal cure properties. By measuring the cure time required to achieve tan delta values representative of early and late‐stage cure conditions, a ratio t₁/t₂ was defined that allowed the cure characteristics of the various systems to be compared. Sustained in vitro release of BSA from glycine‐loaded silicone elastomer covered rod devices was also demonstrated over 14 days. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010