By-product removal

RCM. See Ring-closing metathesis (RCM) Reaction by-products, removing, 83 Reaction extrusion, 204 Reaction index, 237 Reaction injection molding (RIM), 205 Reaction-in-mold (RIM) nylon, 149 Reaction kinetics, 76, 77 Reaction mechanisms, polyesterification, 66-69... 

By-product removal (latent heat) Heat-up incoming feed X X... 

Figure 4.13 Enzymatic by-product removal synthesis of dinitrodibenzyl from nitrotoluene applying a cascade of continuous stirred-tank reactors while degassing with nitrogen...

Figure 4.14 Chemical adducts for by-product removal synthesis of isopropyl-cis-Ag-hexadecanoate from isopropylpalmitate applying a repetitive batch process using a sequence of stirred-tank reactor, extraction module, filtration step and chromatographic downstream processing...

Fig. 7.19 Flow schemes of in-line electrolysis (a) single pass of total water stream, (b) by-pass arrangement, (c) divided cell with by-pass as catholyte, (d) divided cell with catalytic bed for product and by-product removal...

Zeolite-Membrane Reactors for Conversion Enhancement by Product Removal.298... 

FIGURE 10.21 (See color insert following page 588.) Traditional applications of inorganic membrane reactors for (a) conversion enhancement by product removal, (b) permeation of products and reaction coupling, and (c) selectivity enhancement by reactant distribution. 

Effect of Acyl Donors. TTie synthesis of glucose fatty acid esters was investigated with continuous by-product removal in a stirred-tank membrane reactor by azeotropic distillation using EMK containing 20% hexane as reaction solvent and different fatty acids as acyl donors. From previous studies on the lipase-catalyzed synthesis of glucose esters in a solid-phase system (17,19,22,23), it was already known that the fatty acid chainlength had a considerable influence on product formation. This was due... 

SYNTHESIS A well-stirred solution of 0.45 g free base DOB in 2 ml CH2CI2 was treated with 0.37 g triethylamine, cooled to 0 °C, and there was then added a solution of 0.39 g 1,1,4,4-tetramethyl-1,4-dichlorodisilylethylene in 2 mL CH2CI2. The reaction mixture was allowed to return to room temperature, with stirring continued for 2 h. The solvent was removed under vacuum, the residue suspended in hexane, and the insoluble by-products removed by filtration through celite. Removal of the solvent under vacuum gave 0.60 g 1-(4-bromo-2,5-dimethoxyphenyl)-2-(1-aza-2,5-disila-2,2,5,5-tetramethylcyclopentyl)propane as a gold-colored impure semi-solid mass which was used without further purification. 

Ground and surface water applications include water softening [115], water disinfection by-product removal [116], natural organic matter removal [116-117], pesticide removal [118], and removal of a wide range of other pollutants [119]. Nanofiltration also can be used to remove microorganisms and viruses [120-121]. Such applications do not require the low molecular weight selectivity of reverse osmosis and are well suited for low-pressure nanofiltration. 

The process, first disclosed in 1968, was commercialized in 1973. Yields in this process were very high (99%) and ease of operation was excellent. The major difficulty encountered was with catalyst precipitation during product removal. To minimize the problematic catalyst precipitation and to stabilize the catalyst, 10-15% water was included in the reaction mixture and the catalyst -product separation was conducted as an adiabatic flash. The inclusion of large amounts of water and the restriction to an adiabatic flash meant that the conversion was limited by product removal, not the reaction rate, and that there were large recycle streams of acetic acid and water. Additional minor difficulties were the cogeneration of traces of acetaldehyde which ultimately lead to propionic acid and iodine containing impurities. While the propionic acid was removable by distillation (with a dedicated unit of operation), the iodine has proven more problematic. It was important to remove essentially all the iodine (to < 40 ppb) during purification since iodine is a poison for the Pd/Au catalyst used in vinyl acetate production. 

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