Reactive mixing scale

Perbenzoic acid was one of the first peracids used to epoxidize PBD [118, 131]. Internal double bonds are epoxidized quantitatively by perbenzoic acid in the presence of the double bonds of 1,2-inserted butadienes [132]. This one-phase reaction can be used analytically to determine the content of 1,4-inserted units in PBD [131]. The commercial availability of m-CPBA makes it the preferred peroxide for epoxidation [100, 133-139]. m-CPBA epoxidizes double bonds quantitatively, although the 1,4-inserted butadiene units react faster [100]. The final epoxide content of the PBD can, thus, be controlled by the amount of m-CPBA added [138]. Despite its chemical benefits, m-CPBA is not used in large-scale epoxidation because of its high cost and the cost of disposal of mefa-chlorobenzoic acid residue. Epoxidations of PBDs are described with monoperphthalic acid using reactive mixing techniques [140]. The preparation of perphthalic acid from phthalic acid anhydride and hydrogen peroxide in solution was found to be convenient for the preparation of epoxidized polyenes, without notable side reactions [107, 141-143]. 

A considerable amount of carbon is formed in the reactor in an arc process, but this can be gready reduced by using an auxiUary gas as a heat carrier. Hydrogen is a most suitable vehicle because of its abiUty to dissociate into very mobile reactive atoms. This type of processing is referred to as a plasma process and it has been developed to industrial scale, eg, the Hoechst WLP process. A very important feature of a plasma process is its abiUty to produce acetylene from heavy feedstocks (even from cmde oil), without the excessive carbon formation of a straight arc process. The speed of mixing plasma and feedstock is critical (6). 

Epichlorohydrin Elastomers without AGE. Polymerization on a commercial scale is done as either a solution or slurry process at 40—130°C in an aromatic, ahphatic, or ether solvent. Typical solvents are toluene, benzene, heptane, and diethyl ether. Trialkylaluniinum-water and triaLkylaluminum—water—acetylacetone catalysts are employed. A cationic, coordination mechanism is proposed for chain propagation. The product is isolated by steam coagulation. Polymerization is done as a continuous process in which the solvent, catalyst, and monomer are fed to a back-mixed reactor. Pinal product composition of ECH—EO is determined by careful control of the unreacted, or background, monomer in the reactor. In the manufacture of copolymers, the relative reactivity ratios must be considered. The reactivity ratio of EO to ECH has been estimated to be approximately 7 (35—37). 

The characteristic magnitudes of detonation cells for various fuel-air mixtures (Table 3.2) show that these restrictive boundary conditions for detonation play only a minor role in full-scale vapor cloud explosion incidents. Only pure methane-air may be an exception in this regard, because its characteristic cell size is so large (approximately 0.3 m) that the restrictive conditions, summarized above, may become significant. In practice, however, methane is often mixed with higher hydrocarbons which substantially augment the reactivity of the mixture and reduce its characteristic-cell size. 

Phenol ethers, like the parent phenols, are reactive substrates. Phenol ethers like anisole and phenetole are readily nitrated to their picryl ethers, 2,4,6-trinitroanisole and 2,4,6-trinitrophenetole respectively, on treatment with mixed acid composed of concentrated nitric and sulfuric acids at 0 °C. Such reactions are vigorous, prone to oxidative side-reactions, and pose a considerable safety risk. The direct nitration of 2,4-dinitrophenol ethers, obtained from the reaction of 2,4-dinitrochlorobenzene with alkoxides, provides a more practical route to picryl ethers on an industrial scale. ... 

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