CHEM 332 Lecture Notes - Lecture 5: Louis Pasteur, X-Ray, Crystallization
3 Oct 2016
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Document Summary
Louis pasteur and chiral crystals: potassium hydrogen (2r,3r) tartrate, a compound in wine, term racemic acid" comes from wine, discovery of isomers from this compound, pasteur separated crystals of sodium ammonium tartrate to obtain pure enantiomers. Polymorphism: sulphanilamide has three different forms o each have a different melting point aka different stability, melted chocolate that is refrozen will become a different polymorph. Gibbs free energy and polymorphism: difference between the surface energy and the internal energy o spherical droplets (water) minimize the surface area while maximizing area. Stabilizes the unfulfilled h bonds by turning inwards: the size of the crystal can determine the shape o smaller crystals have more surface area, larger have more area, which can change the energy. Nanoscale crystallization reactors: cpg commercially available, synthesize diblock copolymers with hexagonally ordered cylinders o two different polymers within the structure that want to associate with themselves. Polymorphism of roy: 10 different polymorphisms reported, stabilities are ranked.
