Organic chemistr

Reactions such as catalytic hydrogenation that take place at the less hindered side of a reactant are common in organic chemistr-y and are examples of steric effects on reactivity. Previously we saw steric effects on structure and stability in the case of cis and trans stereoisomers and in the preference for equatorial substituents on cyclohexane rings. 

NEW ORGANIC CHEMISTR Y, by H.L. Keys PRACTICAL ORGANIC CHEMISTRY, by Vogel... 

BASIC PRINCIPLES OF ORGANIC CHEMISTR Y, by Roberts Caseno... 

As the science of organic chemistr> slowly grew in the nineteenth century, so too did the number of known compounds and the need fbr a sy-stematic method of naming them. The si stem of nomenclature we H use in this book is that devised by the International Union of Bure and Applied Chemistry (lUPAC, usually spoken as eyc-you pac). 

Dtalkylamine anions like 1J)A are extremely powerftil bases that are much used in organic chemistr> v particularly for the generation od enolate ions from carbonyl compounds (Section 22.tt). 

Chapter 30, Orbitals and Organic Chemistr > Pericyclic Reactions—All the art in this chapter has been redone. 

See, for example, J. March, in Advanced Organic Chemistrs . 4th edn., McGraw-Hill, New York, 1992. 

Levy, G.C. Nelson, G.C. "Carbon-13 Nuclear Magnetic Resonance for Organic Chemistr" Wiley-Interscience, New York, N.Y. 1972. 

Sammes P. G, Comprehensive Organic Chemistr)/ Heterocyclic compounds. Part 20-1, Ed., Pegammon Press, Oxford Vol. 4,1979. p. 976... 

Hudlicky, N4 Chemistr of Organic Fluorine Compounds 2nd ed, Ellis Horwood Ltd Chichester, United Kingdom, John Wiley New York, 1976, pp 36 1... 

Division of Organic Chemistry. V. American Chemical Society. Division of Carbohydrate Chemistre. 

Welch J T, Ed Selective Fluorination in Organic and Bioorganic Chemistr American Chemical Society Washington DC 216... 

WH.WII and Gismid s Texllmnk of Organic Medicinal and Phurmuceiuicai Chemistre... 

Several transition metal phosphate systems are found to catalyze mild oxidations of organic molecules. Catalytic activity is due to transition metal redox couples see Oxidation Catalysis by Transition Metal Complexes and Oxide Catalysts in Solid-state Chemistr, but the phosphate groups are important in determining the underlying and surface structures. 

Inorganic colloids in surface waters may be the oxy/hydroxides of Mn, Fe, Al and Si, as well as carbonates and clays, with a size range from a few nanometres up to millimetres (Thurman (1985), Morel and Hering (1993)). Such colloids have been extensively characterised and modelled (Ledin et al (1995), Wilkinson et al (1995), Filella et al (1993), Leppard et al (1990), Filella and Buffle (1993), Ferret et al (1994), Newman et al (1994)). Colloids in a natural environment often have a negative surface charge and occur in large organic matrices. Solution chemistr) and surface properties control the colloidal stability of these natural particles. 

In summary, there are two scenarios which cause the most severe flux decline. Firstly, poorly soluble organics at low pH (4,5) or in the presence of salt, which is often the case with surface waters, and secondly small colloids, that partially aggregate. Particles prepared with organics in the OPS order exhibit a low flux decline for the small colloids, due to a low rejection and an incomplete adsorption within the pores. The solution chemistr) is important, as pH influences the adsorption of organics and, thus, particle stabilisation. Additionally, calcium can destabilise the previously stable colloids. 

In UF, rejection and fractionation experiments showed that a molecular weight cut-off (MWCO) of smaller than 10 kDa is required to remove a substantial amount of natural organics. Rejection depends on organic type and solution chemistr). The importance of charge effects between organics and membranes was demonstrated. 

---