IJFANS International Journal of Food and Nutritional Sciences

ISSN PRINT 2319 1775 Online 2320-7876


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A literature review of organic solid-state reactions and acyl transfer in molecular crystals of cyclitol derivatives. From its beginnings in the early 19th century, knowledge in the area of organic chemistry has mostly been accumulated through the study of reactions in solution. The earliest chemists were probably prejudiced by the Greek philosopher Aristotle's reflection 'No coopora nisi fluida' or 'No reaction occurs in the absence of solvent', in the times when philosophy and religion had a major influence on science. However, today there are many examples of reactions known to proceed in the absence of solvent or in the crystalline state, with many reviews and a few books" dealing with the subject. Solid-state reactions can be developed as green reactions on account of their solvent-free nature and simplicity in workup and purification. While spectroscopic methods have been used for understanding solution-state phenomena, techniques developed to study solid-state reactions include single crystal and powder X-ray diffraction, differential scanning calorimetry, electron microscopy, infrared and solid-state nuclear magnetic resonance spectroscopy. Because of the topochemical control imposed by the crystal lattice, reactions in crystals often occur with ease and great selectivity. Reactivity in the crystalline form is mainly determined by weak contacts and the closeness of reactive groups, while reactivity in solution is determined by the electrical characteristics of molecules. In contrast to the gaseous and solution states, where molecules are free to constantly reorient with respect to each other, the crystal lattice in the solid state serves to predispose the reactants in a favourable orientation for the reaction and thwart changes in their relative orientation with respect to the neighbouring molecules. The crystal lattice's pre-organization of the reactive groups is a factor that contributes to the increased rate and/or stereochemistry of the product produced in crystallisation processes. Crystal packing pressures may reduce the entropy of a reaction's activation by either limiting the molecule conformation, resulting in an intramolecular reaction, or by fixing the relative orientation of the sites in the crystal lattice, allowing for intermolecular processes. However, a variety of additional interactions in the crystal lattice (such as hydrogen bonding, halogen bonding, electrophile-nucleophile interactions, and so on) may prevent potentially reactive groups from forming reactive organisations

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