Reduction, accelerating substitution

Han et al. [64, 66] reported the synthesis of highly conductive and thermally stable self-doped mercaptopropanesulfonic-acid-substituted polyanilines by the concurrent reduction and substitution reaction between polyaniline and a nucleophile. These reactions were carried out on both electrochemically generated and free standing polyaniline films prepared from emeraldine base dissolved in N-methylpyrrolidinone. The electrochemically prepared films were dedoped with 5 % aqueous NaiCOs to convert them the into the emeraldine base form. The sulfonated polyaniline was prepared by reaction of a polyaniline emeraldine base film with 0.1 M 3-mercapto-l-propanesulfonic acid sodium salt in methanol under nitrogen at room temperature for approximately 14h [66]. A catalytic amount (0.01 M) of acetic acid was reported to accelerate the reaction. The resulting sulfonated polyaniline film was thoroughly rinsed with methanol, followed by 5 % aqueous NaiCOs to remove reactants. 

In the reduction of substituted nitrobenzenes (HCOONa, which accelerated the reaction, was also added) electron-withdrawing groups favoured the reaction, but... 

The classifier described above works very well with coarse particles where exact splits are not needed. Typical applications are in connection with ball or rod mills for reduction to particle sizes between 8- and 20-mesh. These classifiers have high capacities they lift coarse solids for return to the mill, so that auxiliary conveyors and elevators are not required. There are other types of classifier that must be usual for close separations with fine particles. One such device is the centrifugal classifier its action bears a strong resemblance to that of the crossflow classifier, but the settling is greatly accelerated by the substitution of centrifugal force for gravitational force. 

Nielson125 reports the synthesis of 7-((V-aIkylamino)- and T-(N,N-di-alkylamino)-l,3,5-triazaadamantanes by reductive alkylation of 94, which is obtained from 91 by an improved hydrogenation procedure (rhodium-charcoal catalyst, 25.5 psi). Paper chromatography54 and the Kovats indices and relative elution volumes of 1,3,5-triazaadamantane derivatives are measured.55 7-Amino-l,3,5-triazaadamantane is used as a vulcanization accelerator.127 7-(N,N-Dialkylamino)-l,3,5-triazaadamantanes are utilized as a new class of high-density fuel (DIADAM).128 Some 7-substituted 1,3,5-triazaadamantanes have bacteriostatic and fungistatic activity.129 7-Bromo-,... 

Ion-pairing effects may be crucial in determining the competition between radical and nonradical reactions. Recent investigations have shown that ion pairing accelerates the reduction of nitroarenes in alcoholic media.60 Therefore, the higher yields of substitution products often obtained in the absence of ion pairing are due, at least in some cases, not only to the promotion of substitution, but also to the depression of radical pathways. 

Usanov and Yamamoto recently found that catalytic amounts of Co(TPP) 367 led to a dramatic rate acceleration of Nozaki-Kishi-Hiyama reactions catalyzed by chromium complex 368 (Fig. 101) [460]. The authors attributed the rate enhancement to initial reduction of 367 to a Co(I) complex. The latter is able to undergo an Sn2 substitution at propargyl bromide 366 giving an allenylCo(ffl) species. It was proposed that its homolysis leads to allenyl radical 366A, which couples to Cr(II) complex 368. The resulting allenyl Cr(III) complex adds in an SN2 process... 

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