Future Reactions

The search for other reversible reactions that would be suitable for use in DCLs is ongoing. Using computational methods, Houk et al. have investigated substitu- 

41 Kudo, H., Shigematsu, K Mitani, K Nishikubo, T., Kasuga, N.C., Uekusa, 

44 Alajarin, M., Berni,)., Lopez-Leonardo, C., and Steed, J.W. (2008) Chem. Commun., 2337-2339. 

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Initiation with only one portion of ceric amnoniiM nitrate (rather than with two portions added one hour apart) reduces both the conversion of monomer to polymer and the water absorbency of the fined product. Based on these results, starch in future reactions was gelatinized by heating for 60 min at 95 C, to more closely simulate conditions of continuous steam jet cooldng 02) r %diich would be used commercially. Also, polymerizations were initiated with two portions of ceric ammonium nitrate dissolved in IH HNQs, seponification mixtures were stirred continuously rather than intermitt Ttly (as a matter of convenience), and absorbent polymers were dried at 40 C. 

Some patients who have had an anaphylactic reaction wear a medical alert bracelet or necklace with an inscription endorsed by a doctor that alerts other doctors to the possible cause of any future reaction. 

It is generally assumed that electrons are transferred one by one (cases reported to be direct two-electron transfers 109 110 may actually be two very closely spaced one-electron transfers 11 ). This postulate immediately tells us that the first intermediate formed from a neutral substrate must be a cation radical in anodic oxidation and an anion radical in cathodic reduction and a neutral radical from oxidation of an organic anion and reduction of an organic cation. This has been amply verified both by electrochemical techniques and by ESR studies in inert SSE s 29,65) unfortunately, such results do not allow us to draw conclusions regarding the future reactions of these types of intermediates, as will be outlined in the following section. 

The mercury may be easily recovered for future reactions of a similar type. This is conveniently done by washing the recovered mercury first with 95% ethanol to remove the sodium and then with water until the water washings are clear and colorless. The mercury is then suitable for additional sodium amalgam experiments without redistillation. 

Patients with previous severe reactions should have emergency treatments, such as epinephrine and histamine blockers, ready upon re-exposure in case a future reaction occurs. 

Dicy do hexyl carbodiimide (DCC) should not be used as the insoluble dicyclohexyl urea (DCU) by-product is very difficult to remove, leaving residual DCU that can contaminate future reactions. Also, no dimerization of the HOBT ester of 3-carboxypropane sulfonamide 6 occurs as the sulfonamide is nonreactive toward HOBT esters. This was also observed by Ellman (38). 

As a reminder (see Section 2-3), the use of the symbol for the free proton, in the above equation is for convenience, and we will encounter it in future reaction schemes and mechanisms. Nonetheless, bear in mind that It in solution is always associated with a Lewis... 

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