The extreme physical properties of the CoRoT-7b super-Earth

The search for rocky exoplanets plays an important role in our quest for extra-terrestrial life. Here, we discuss the extreme physical properties possible for the first characterised rocky super-Earth, CoRoT-7b (R(pl) = 1.58 +/- 0.10 R(Earth), M(pl) = 6.9 +/- 1.2 M(Earth)). It is extremely close to its star (a = 0.0171 AU = 4.48 R(st)), with its spin and orbital rotation likely synchronised. The comparison of its location in the (M(pl), R(pl)) plane with the predictions of planetary models for different compositions points to an Earth-like composition, even if the error bars of the measured quantities and the partial degeneracy of the models prevent a definitive conclusion. The proximity to its star provides an additional constraint on the model. It implies a high extreme-UV flux and particle wind, and the corresponding efficient erosion of the planetary atmosphere especially for volatile species including water. Consequently, we make the working hypothesis that the planet is rocky with no volatiles in its atmosphere, and derive the physical properties that result. As a consequence, the atmosphere is made of rocky vapours with a very low pressure (P <= 1.5 Pa), no cloud can be sustained, and no thermalisation of the planet is expected. The dayside is very hot (2474 +/- 71 K at the sub-stellar point) while the nightside is very cold (50-75 K). The sub-stellar point is as hot as the tungsten filament of an incandescent bulb, resulting in the melting and distillation of silicate rocks and the formation of a lava ocean. These possible features of CoRoT-7b could be common to many small and hot planets, including the recently discovered Kepler-10b. They define a new class of objects that we propose to name ""Lava-ocean planets"". (C) 2011 Elsevier Inc. All rights reserved.

Isosorbide Polyesters from Enzymatic Catalysis

The synthesis of isosorbide aliphatic polyesters is demonstrated by the use of Novozym 435, a catalyst consisting of Candida antarctica lipase B immobilized on a macroporous support Several experimental procedures were tested and azeotropic distillation was most effective in removing low mass byproduct Furthermore, the use of diethyl ester derivatives of diacid comonomers gave isosorbide copolyesters with highest Isolated yield and molecular weights The length of the diacid aliphatic chain was less restrictive, but with a clear preference for longer aliphatic chains The molecular mass values of the obtained products were equivalent or higher than those obtained by nonenzymatic polymerizations, a clear illustration of the potential of enzymatic over conventional catalysis The ability of Novozym 435 to catalyze the synthesis of isosorbide polyester with weight-average molecular weights in excess of 40000 Da was unexpected given that isosorbide has two chemically distinct secondary hydroxyl groups This is the first example in which isosorbide polyesters were synthesized by enzyme catalysis, opening a large array of possibilities for this important class of biomass-derived building blocks Because these polymers are potential biomaterials the total absence of conventional Lewis acid catalyst residues represents a major Improvement in the toxicity of the material

Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS)

An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) mu g L-1, whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected, ethyl acetate is the major ester in whiskey and rum, followed by ethyl lactate for samples of rum. Nevertheless, whiskey samples exhibit ethyl lactate at contents lower or at the same order of magnitude of the fatty esters.