Reactive mixing power

In the second half of 1994 a central insert of 7 BN-800 type reactor fuel subassemblies with mixed power-grade plutonium fuel was assembled at the BN-800 reactor mock-up with the reactivity compensation rod system being withdrawn. 

CH2(0CH20N02)2, mw 198.11, N 14.14%, OB to C02 —8.08%, liq. Prepn from formaldehyde or trioxymethylene with mixed acid. Impact sensitivity FI is 6% of PA. Power by lead block test is 148% of PA, and the material is described as not very powerful . Chemically unstable and reactive with moisture Refs 1) Beil — not found 2) Blatt, OSRD 2014(1944)... 

Gas-expanded liquids (GXLs) are emerging solvents for environmentally benign reactive separation (Eckert et al., op. cit.). GXLs, obtained by mixing supercritical CO2 with normal liquids, show intermediate properties between normal liquids and SCFs both in solvation power and in transport properties and these properties are highly tunable by simple pressure variations. Applications include chemical reactions with improved transport, catalyst recycling, and product separation. 

There are a number of other reasons for carrying out size reduction. It may, for example, be necessary to break a material into very small particles in order to separate two constituents, especially where one is dispersed in small isolated pockets. In addition, the properties of a material may be considerably influenced by the particle size and, for example, the chemical reactivity of fine particles is greater than that of coarse particles, and the colour and covering power of a pigment is considerably affected by the size of the particles. In addition, far more intimate mixing of solids can be achieved if the particle size is small. 

Pentaerythritol tetranitrate (PETN) (3) is a powerful explosive which exhibits considerable brisance on detonation (VOD 8310 m/s at = 1.77 g/cm ). It is the most stable and least reactive of the common nitrate ester explosives. The relatively high sensitivity of PETN to friction and impact means that it is usually desensitized with phlegmatizers like wax and the product is used in detonation cord, boosters and as a base charge in detonators. Pentaerythritol tetranitrate can be mixed with synthetic polymers to form plastic bonded explosives (PBXs) like detasheet and Semtex-IA. A cast mixture of PETN and TNT in equal proportions is known as pentolite and has seen wide use as a military explosive and in booster charges. The physical, chemical and explosive properties of PETN commend its use as a high explosive. 

The reactivity of phenols to electrophilic nitration is illustrated further by the facile conversion of m-nitrophenol to 2,3,4,6-tetranitrophenol with anhydrous mixed acid. The latter is a powerful explosive, but chemically unstable, like all polynitroarylenes containing a nitro group positioned olp- to other nitro groups. 

The presence of two methyl groups in m-xylene makes it a more reactive substrate than toluene, but as a consequence, this substrate is more susceptible to oxidation. Therefore, the nitration of m-xylene requires lower temperatures and the use of less concentrated mixed acid. In fact, the nitration of either 2,4- or 2,6-dinitro-m-xylenes to 2,4,6-trinitroxylene (TNX) can be achieved with mixed acid containing up to 10 % water. TNX is a less powerful explosive than TNT and has a poor oxygen balance (—78.4 %). 

It is known that certain Friedel-Crafts acylations of reactive aromatics may proceed with a small amount of catalyst or even, to some extent, with no catalyst at all.41 Effective catalysts are Fe, FeCl3, ZnCl2, iodine, and hydroiodic acid. However, satisfactory yields are usually obtained with activated and polynuclear aromatics, and heterocycles. The mixed anhydrides acyl triflates are also powerful acylating agents without catalyst.34... 

Earlier studies of numerous research groups have considerably helped to establish a basic understanding of the mechanism of various types of micellar catalysis. Several excellent accounts of prior work have been published [4-8]. Pseudophase treatments of reactivity in association colloids provide a chemically satisfying approach with predictive power [9]. The present section of this article focuses on a few examples from recent literature that explore the catalytic effects observed from aqueous micellar or mixed-micellar aggregates. 

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