More Recent Results

Some further investigation on the electropolymerization in situ of diacetone acrylamide has been performed by the author of this review. 

Current-potential curves obtained at a Zn electrode in acid buffer (pH = 2) for various diacetone acrylamide cones. 0.00 M 0.06 M 0.30 M 

When the coatings obtained this way were examined, not only was the resultii morphology far better but also the coulombic yield (mg/coulombs) (see Table 2) was tremendoudy higher for the samples obtained with small potential differences applM as an instance the yield, which was about 300 g/F(araday) at 3.5 V was reduced to 170 g/F at 5 V and to an order of magnitude below 10 g/F at 6 V. 

However, it must be noted that the presence of some low ccmcentration rtf a strong acid favors the polymerization in fact when a moncxner soluticm of a neutral salt electrolyte was electrolyzed, the results were less satisfactory as may be deduced from the current trends illustrated by Fig. 9. 

Monom cone. H2SO4 cone. Voltage in V Yield in ing/cm Yield in mg/Coulomb 

---

McClellan s and Hamsberger s survey, which embraced a considerable variety of solids including carbons, metal oxides and organic polymers such as polythene, arrived at a mean value of 20-2 A, with a standard deviation of 1-6 A. Other more recent results, likewise based on = 16-2 A, ... 

More recent results, however, throw some doubt on this interpretation. The isotherms in Fig. 5.22 were determined after successive oatgassings at (1) 25°C, (2) lOO C, (3) 150 C, (4) SOO C, and (5) 25 C, respectively. It will be noted (a) that only isotherms (4) and (5) exhibit a Point X and that they are nearly parallel at pjp° > 0-1 (b) that isotherms (2) and (3) are similarly parallel in the same range and (c) that isotherms (1) and (5), though both obtained after outgassing at 25 C, are quite different in shape. 

The more recent results of Scheme 18 can be summarized as follows the less hindered isomer is formed unless the substituent has a lone pair, the electrostatic field of which enhances the nucleophilicity of the adjacent nitrogen atom. This is true not only for pyridine and pyrazole, but probably also for CHO and C02Et. 

The methyl ether of A-aeetyliodocolehinol (III C. OH C. OMe) is oxidised by hot permanganate solution to 4-iodo-5-methoxyphthalie acid (IV). The latter is unchanged when the substituents are interchanged in position (as required by the more recent results of Barton, Cook and Loudon described below), so these observations imply the pi ence of a benzene ring in W-acetyliodoeolehinol, with iodine as a... 

The radiation chemistry has been mainly discussed in terms of degradation reactions (as above) involving the loss of gaseous products and the irreversible change of the stoichiometry [203]. However, more recent results showed that polymers irradiated with radiation deposit-... 

More recently, results of exposure tests for 10 years in a severe industrial environment at Stratford, London, have been reported by the Fulmer Research Institute". A range of pure and alloy specimens, anodised to a maximum film thickness of about 25 m, was exposed at an angle of 45°. 

In discussing more recent results it must be mentioned, that there are three kinds of water molecules around the DNA ... 

PETN is insoluble in water but is soluble in a variety of organic solvents and particularly in acetone. This is clearly shown in Table 1 which contains the data of Urbariski Kwiatkowski (Ref 3), and in Table 2 which shows the more recent results of Roberts and Dinegar (Ref 21)... 

The materials obtained by this idealized equation have also been termed polysulfuroxides in the older hterature. However, more recent results showed that they also contain hydrogen and therefore are probably polysulfane oxides of the types HS(S 0)xSH or HS(S 0)xOH [3, 88]. Due to the simultaneous thermal decomposition with formation of SO2 the sulfur content is higher than expected from Eq. (38) and from the general formula. All these compounds produce S2O on heating in a high vacuum which is a typical reaction for compounds containing oxidized sulfur chains or rings. 

Research into cluster catalysis has been driven by both intrinsic interest and utilitarian potential. Catalysis involving "very mixed -metal clusters is of particular interest as many established heterogeneously catalyzed processes couple mid and late transition metals (e.g., hydrodesulfurization and petroleum reforming). Attempts to model catalytic transformations arc summarized in Section II.F.I., while the use of "very mixed -metal clusters as homogeneous and heterogeneous catalysis precursors are discussed in Sections I1.F.2. and I1.F.3., respectively. The general area of mixed-metal cluster catalysis has been summarized in excellent reviews by Braunstein and Rose while the tabulated results are intended to be comprehensive in scope, the discussion below focuses on the more recent results. 

Evans . The more recent result is to be preferred in view of the wider range of Cr(VI) concentration employed. 

The F n.m.r. spectra of the P compounds (18) indicate that the PAra(OEt)2 group has very weak electron-withdrawing properties both inductively and mesomerically. This is to be contrasted with (19) where the PF4 group was found to be the most strongly withdrawing group in a range of P , P , and P compounds. This more recent result shows that... 

Porous packed systems represent in addition to the hydrodynamic effect, the possibility for separation due to size-related exclusion of particles from the pores, essentially LEG. In this section a brief overview of some of o ir more recent results pertaining to the question of pore size distribution effects will be given, fore detailed discussions are presented elsewhere (23>2U). 

Reviews of w/o-ME-based LLE of biomolecules are readily available [4,57,102-104]. However, new results have been generated in this field since the publication of the cited reviews. For instance, there has been a large amount of research involving new surfactant and surfactant systems, particularly those involving nonionic and natural surfactants such as phosphatidylcholine and bioaffinity surfactants (Table 1), in order to increase biocompatibility and selectivity and prevent denaturation that occurs using ionic surfactants. The more recent results along these lines will be presented here, along with an overview of the LLM process. 

Since these developments became known the importance of steric effects on the reactivity of free radical reactions has also been more clearly recognized and more thoroughly investigated1 11 Some more important and more recent results along these lines are the topic of this review. 

Other Monomer Systems. Very slight modifications are required to make the model applicable to emulsion homopolymerization of vinyl chloride (VCM). An initial study on PVC reactors has been reported in (69) and some more recent results following will finely illustrate the case. 

In order to explore the generality of this new domino reaction the conversion of various primary amines with 2-341 and the cyclohexane analogue was investigated (Scheme 2.81). For example, the reaction proceeds with high yields when benzyl- or (2-phenylethyl)amine are used (entries 1 and 2). In comparison, sterically more hindered amines such as 2-butylamine produced much lower yield (entry 4) Furthermore, the reaction tolerates other functional groups, such as an unprotected hydroxyl group (entry 5), and variation of the enone ring size is possible (entries 6 and 7). More recent results have revealed that the addition of Sn(OTf)2 or In(OTf)2 makes the transformation more reliable. 

Particularly the step of CC-bond formation is of interest, and has been investigated thoroughly by use of organometallic model compounds a survey of this subject has been given by IV. A. Herrmann [6], In the following, some more recent results are discussed briefly. 

Cramer and Kampe (1965), in fact, proposed a specific interaction between the included substrate and the cycloamylose hydroxyl groups to explain accelerated rates of decarboxylation. In view of the more recent results, particularly the insensitivity of the rate accelerations to the structure of the substrate and the pH independence, a nonspecific microsolvent effect now seems more likely. 

Before discussing recent studies on the ring expansion reactions of phenylcarbene and phenylnitrene, we will describe some of the earlier experimental and theoretical work on these molecules. Our purpose here is to give a brief overview, in order to provide a context for the discussion of more recent results. For detailed descriptions of the chemistry of arylcarbenes and arylnitrenes, we refer the reader to the many excellent reviews in this area.1,2... 

---