Chemical Reactors. Problem 1: A simple ODE (chaos in the atmosphere) (2011-2012 Course)

Wording of problem 1: A simple ODE (chaos in the atmosphere).

Chemical Reactors. Problem 2: Constant pressure adiabatic stirred batch reactor with variable heat capacities (2011-2012 Course)

Wording of problem 2 (week 3, 17/10/11).

Chemical Reactors. Problem 2: Constant pressure adiabatic stirred batch reactor with variable heat capacities. Solution (2011-2012 Course)

Chemical Reaction Engineering. Course 2011-12. Solution of problem 2: constant pressure adiabatic stirred batch reactor with variable heat capacities.

Chemical Reactors. Problem 3: Isothermal plug flow reactor with multiple reactions (2011-2012 Course)

Wording of problem 3: Isothermal plug flow reactor with multiple reactions.

Binap-gold (I) versus Binap-silver trifluoroacetate complexes as catalysts in 1,3-dipolar cycloadditions of axomethine ylides

The 1,3-dipolar cycloaddition between azomethine ylides and alkenes is efficiently catalysed by [{(Sa)-Binap-Au(tfa)}2] (Binap=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl; tfa=trifluoroacetyl). Maleimides, 1,2-bis(phenylsulfonyl)ethylene, chalcone and nitrostyrene were suitable dipolarophiles even when using sterically hindered 1,3-dipole precursors. The results obtained in these transformations improve the analogous ones obtained in the same reactions catalysed by [Binap–Ag(tfa)]. In addition, computational studies have also been carried out to demonstrate both the high enantioselectivity exhibited by the chiral gold(I) complex, and the non-linear effect observed in this transformation.

Enantioselective 1,3-dipolar cycloadditions of azlactones and electrophilic alkenes catalyzed by dimeric BinapAuTFA complexes

Glycine-derived azlactones react with maleimides using (S)- or (R)-dimeric BinapAuTFA complexes affording the corresponding cycloadducts in good yields and high enantioselections (up to 99% ee). The intermediate carboxylic acids are treated with trimethylsilyldiazomethane and isolated as Δ¹-pyrroline methyl esters. These cycloadducts are transformed into exo-proline derivatives by reduction with NaBH3CN in acidic media. On the other hand, N-benzoylalanine-derived oxazolone reacts with tert-butyl acrylate providing the cycloadduct with the ester group at the 3-position with a trans-relative configuration with respect to the methyl ester group.