DNBP process

Virtually all nitration reactions involve electrophillic attack by nitronium ions, NO2. Consequently, reactions can be regulated by controlling the concentration of nitronium ions in solution. The conditions required for the nitration reaction vary greatly with the reactivity of the aromatic substrate. The nitration mixture required for introduction of the second nitro group into benzene to prepare dinitrobenzene and concentrated nitric and sulfuric acids at 95°C is unsuitable for dinitration of alkylated phenol because it provides the conditions for an uncontrollable exothermic reaction. The DNBP process described above was based on controlling the nitration conditions and has the advantage of having very few side reactions because it is a two-phase system with nitration reactivity based on mass transfer between phases. 

The process of direct nitration of alkylated phenols was developed and implemented in the manufacturing plant. Later, the process was extended to nitration of phenol and several other alkylated phenols, substituted aniline compounds, and so on, by McDaniel and Gross. The process was implemented successfully to meet customer demand because of considerable reduction of in-process pollution streams, which could be treated in the plant treatment facihty with minimal plant modifications and ease of operation. The problems of treating and disposing of process wastes off-site were eliminated, making the process feasible compared to the DNBP process. 

Our laboratory investigations indicated that the purity of the dinitro compounds prepared by homogeneous or direct nitration would not exceed 90 2%. On the other hand, achieving product purity between 95 and 98% using the traditional sulfonation process followed by nitration was no problem. Since the pesticide DNBP was required to be at least 95% pure, the direct nitration process could not be adopted for that product. In this particular case, the client needed approximately a 22% solution of DNOC in styrene. Product testing by the user indicated that the DNOC purity requirement for the styrene monomer stabilizer solution was not critical as long as it exceeded 90%. The final formulation contained 22 to 24% DNOC in styrene. The product met the specifications, was tested by the user, and performed well in field tests. The product also had no chlorinated compounds present even in trace amounts as specified by the user. 

Another intriguing photochemical reaction known for over 70 years is the photo-induced and thermally activated proton transfer between the colorless CH and blue NH forms of 2-(2, 4 -dinitrobenzyl)pyridine (DNBP). The reaction process was... 

The fundamental idea of ATRP is the halogen exchange in the polymerizing system between the halogen terminated growing polymer chain/Cu(l) dNbP complex and macroradical/Cu(II) dNbP complex. Chain propagation is a first order process while termination is a second order reaction. For conventional bulk or solution ATRP the equilibrium is strongly shifted to the left. The free... 

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