Nanosized sulfated zirconia with Brønsted acidic sites has been prepared by a simple calcination in the absence of any solvent. XRD patterns reveal that the sulfated zirconia mainly consists of tetragonal crystalline zirconia with average size of about 7 nm, which is further confirmed by TEM images. N2 adsorption data show that the nanosized sulfated zirconia has high surface area (165-193 m2/g) and exhibits uniform pore distribution aggregated by zirconia nanoparticles. IR spectra of samples show that the sulfur species in the nanosized sulfated zirconia is a little different from that in conventional sulfated zirconia. Furthermore, IR spectra of adsorbed pyridine indicate that the nanosized sulfated zirconia contains relatively more Brønsted acidic sites than conventional sulfated zirconia. Catalytic tests show that the nanosized sulfated zirconia exhibits much higher activity than conventional sulfated zirconia in catalytic esterification of cyclohexanol with acetic acid.

Solanaceous medicinal plants produce tropane alkaloids (TAs). We discovered a novel gene from Atropa belladonna, AbPPAR, which encodes a phenylpyruvic acid reductase required for TA biosynthesis. AbPPAR was specifically expressed in root pericycles and endodermis. AbPPAR was shown to catalyze reduction of phenylpyruvic acid to phenyllactic acid, a precursor of TAs. Suppression of AbPPAR disrupted TA biosynthesis through reduction of phenyllactic acid levels. In summary, we identified a novel enzyme involved in TA biosynthesis.

Particularly relevant in the context of polymorphism is understanding how structural, thermodynamic, and kinetic factors dictate the stability domains of polymorphs, their tendency to interconvert through phase transitions, or their possibility to exist in metastable states. These three aspects were investigated here for two 4′-hydroxyacetophenone (HAP) polymorphs, differing in crystal system, space group, and number and conformation of molecules in the asymmetric unit. The results led to a Δf G m°-T phase diagram highlighting the enantiotropic nature of the system and the fact that the Z′ = 1 polymorph is not necessarily more stable than its Z′ = 2 counterpart. It was also shown that the form II → form I transition is entropy driven and is likely to occur through a nucleation and growth mechanism, which does not involve intermediate phases, and is characterized by a high activation energy. Finally, although it has been noted that conflicts between hydrogen bond formation and close packing are usually behind exceptions from the hypothesis of Z′ = 1 forms being more stable than their higher Z′ analogues, in this case, the HAP polymorph with stronger hydrogen bonds (Z′ = 2) is also the one with higher density.