Batch hydrolysis conditions

Not many operating data of large-scale hquid/hquid reactions are published. One study was made of the hydrolysis of fats with water at 230 to 260°C (446 to 500°F) and 41 to 48 atm (600 to 705 psi) in a continuous commercial spray tower. A small amount of water dissolved in the fat and reacted to form an acid and glycerine. Then most of the glycerine migrated to the water phase. Tlie tower was operated at about 18 percent of flooding, at which condition the HETS was found to be about 9 m (30 ft) compared with an expec ted 6 m (20 ft) for purely physical extrac tion (Jeffreys, Jenson, and Miles, Trans. In.st. Chem. Eng., 39, 389-396 [1961]). A similar mathematical treatment of a batch hydrolysis is made by Jenson and Jeffreys (In.st. Chem. Engrs. Symp. Ser, No. 23 [1967]). 

BATCH HYDROLYSIS OF ACETIC ANHYDRIDE EXAMPLE OF REACTION WITH HEAT EFFECTS UNDER ADIABATIC CONDITIONS... 

As ultimate proof of the kinetic model, a fit of time-courses of batch reactor experiments was performed (Fig. 7-21). Initial concentrations of the components over a significant range were chosen to yield hydrolysis conditions (1) and synthesis conditions (2) respectively. Additionally, the equilibrium positions of corresponding experiments A, B and C were chosen to be identical. Figure 7-21 shows a good correlation of calculated and measured data over the whole range of the conversion, for hydrolysis as well as for synthesis. 

The ratio of cycHc to linear oligomers, as well as the chain length of the linear sdoxanes, is controlled by the conditions of hydrolysis, such as the ratio of chlorosilane to water, temperature, contact time, and solvents (60,61). Commercially, hydrolysis of dim ethyl dichi oro sil a n e is performed by either batch or a continuous process (62). In the typical industrial operation, the dimethyl dichi orosilane is mixed with 22% a2eotropic aqueous hydrochloric acid in a continuous reactor. The mixture of hydrolysate and 32% concentrated acid is separated in a decanter. After separation, the anhydrous hydrogen chloride is converted to methyl chloride, which is then reused in the direct process. The hydrolysate is washed for removal of residual acid, neutralized, dried, and filtered (63). The typical yield of cycHc oligomers is between 35 and 50%. The mixture of cycHc oligomers consists mainly of tetramer and pentamer. Only a small amount of cycHc trimer is formed. 

The advance of sulfur trioxide as sulfating agent largely depended on advances in sulfonation/sulfation reactor development and changes in raw material quality. Undiluted sulfur trioxide cannot be used as a sulfating agent except in special cases where suitable equipment is used because of its violent nature. Sulfur trioxide diluted in an inert gas, usually air, when used in batch processes can cause excessive dehydration and dark-colored products. However, batch processes were used years ago and inert liquid solvents were often suggested or used to moderate the reaction. Inadequate reaction conditions lead to a finished product that can contain dialkyl sulfate, dialkyl ether, isomeric alcohols, and olefins whereas inadequate neutralization conditions can increase the content of the parent alcohol due to hydrolysis of the unstable acid sulfate accompanied by an increase of mineral sulfate. 

The glycolysis of PETP was studied in a batch reactor at 265C. The reaction extent in the initial period was determined as a function of reaction time using a thermogravimetric technique. The rate data were shown to fit a second order kinetic model at small reaction times. An initial glycolysis rate was calculated from the model and was found to be over four times greater than the initial rate of hydrolysis under the same reaction conditions. 4 refs. 

Different effects of formaldehyde on the hydrolysis of urea are reported. On the one hand, Garrido and colleagues,3 applying anoxic conditions, observed that an inhibitory effect started at 50 mg/L formaldehyde and the levels of inhibition were 50% and 90% for concentrations of formaldehyde of 100 mg/L and 300 mg/L, respectively. Similar effects were found by Campos and colleagues,33 working with an anoxic USB, who observed that formaldehyde concentrations in the reactor of 250 to 300 mg/L caused an inhibition of around 53%. This inhibition on the ureolytic activity was also reported by Walker.36 On the other hand, Eiroa and colleagues37 carried out batch assays at different initial urea concentrations from 90 to 370mg/L N-urea in the presence of 430 mg/L formaldehyde. They observed that a complete hydrolysis was achieved and initial urea hydrolysis rates remained constant. 

The C-5 sugar alcohols produced from the hydrolysis of hemicellulose are both xylitol and arabitol [6], Equivalence testing was performed with Ni/Re catalyst in the batch reactor to verily similar performance between xylitol and arabitol feedstocks. The operating conditions were 200°C and 8300kPa H2 using the procedure outlined in section Catalyst Screening section. 

Similarly, hydrolysis of tertiary amides of carboxylic acids is usually slow under conventional conditions. Hydrolysis of a morpholide occurred in only 48% yield with 2M HC1 at reflux after 4h, yet proceeded in 70% yield after only 10 min at 200 °C in the MBR (Scheme 2.2) [26]. The convenience of operation and the rapid throughput enabled preparation of multiple batches of the corresponding acid in a few hours. 

Monoglyceride (MG) is one of the most important emulsifiers in food and pharmaceutical industries [280], MG is industrially produced by trans-esterification of fats and oils at high temperature with alkaline catalyst. The synthesis of MG by hydrolysis or glycerolysis of triglyceride (TG) with immobilized lipase attracted attention recently, because it has mild reaction conditions and avoids formation of side products. Silica and celite are often used as immobilization carriers [281], But the immobilized lipase particles are difficult to reuse due to adsorption of glycerol on this carriers [282], PVA/chitosan composite membrane reactor can be used for enzymatic processing of fats and oils. The immobilized activity of lipase was 2.64 IU/cm2 with a recovery of 24%. The membrane reactor was used in a two-phase system reaction to synthesize monoglyceride (MG) by hydrolysis of palm oil, which was reused for at least nine batches with yield of 32-50%. 

The compounds in a suitable solvent were subcutaneously injected into mice. Methyl fluoroacetate was always injected, under the same conditions, into a batch of mice as a control. The /9-carbon atom in /9-2-fluoroethoxypropionic acid and in /9-3-fluoropropoxypropionic acid is linked to the ether oxygen atom, and if/9-oxidation of these compounds takes place in vivo, the hydrogen carbonate of the fluoro alcohol is formed. One would expect this to have approximately the same toxicity as the alcohol itself, since the latter would be produced either by hydrolysis or by elimination of carbon dioxide ... 

Since protein adsorption to an anion exchange resin is reversible and does not constitute a classical immobilization, the ability of the resins to retain activity under various conditions must be determined. Macrosorb KAX DEAE bound -D-glucosidase was tested with solutions of primary interest for their final application. Several batch washes of a 1% w/v slurry were required to ensure complete equilibrium elution for a given concentration, as determined from the absence of pNPG units in subsequent washes. Several salt solutions of typical fermentation media components were tested. These included 3 mM to 50 mM solutions of MgSO, KHgPO, NaQ, and sodium acetate. Also, incubations with cellulase solutions were tested to determine if the proteins present in a cellulose hydrolysis would displace the -D-glucosidase. Both of these displacement studies were carried out at 22°C and 40 C. 

The catalyst components are generally dissolved in methyl acetate which acts as both reactant and solvent. Other solvents may be used and in fact, upon several batch recycles where lower boiling products are distilled off, the solvent is an ethylidene diacetate-acetic acid mixture. Any water introduced in the reaction mixture will be consumed via ester and anhydride hydrolysis, therefore anhydrous conditions are warranted. Typical batch reaction examples are presented in Table 1. There is generally sufficient reactivity when carbon monoxide and hydrogen are present at 200-500 psi. Similar results were obtained from the pilot plant using a continuous stirred tank reactor (CSTR). The reaction can also be run continuously over a supported catalyst with a feed of methyl acetate, methyl iodide, CO, and hydrogen. 

Vibratory milling also yields substantial increases in the rates of dilute acid hydrolysis of all four substrates nearly nine-fold for cotton linters and roughly five-fold for the three lignocelluloses. Increases in maximum sugar yields under simple batch conditions ranged from 60% to 140% over the yields for the unmilled materials. 

Enzymes are biocatalysts constructed of a folded chain of amino acids. They may be used under mild conditions for specific and selective reactions. While many enzymes have been found to be catalytically active in both aqueous and organic solutions, it was not until quite recently that enzymes were used to catalyze reactions in carbon dioxide when Randolph et al. (1985) performed the enzyme-catalyzed hydrolysis of disodium p-nitrophenol using alkaline phosphatase and Hammond et al. (1985) used polyphenol oxidase to catalyze the oxidation of p-cresol and p-chlorophenol. Since that time, more than 80 papers have been published concerning reactions in this medium. Enzymes can be 10-15 times more active in carbon dioxide than in organic solvents (Mori and Okahata, 1998). Reactions include hydrolysis, esterification, transesterification, and oxidation. Reactor configurations for these reactions were batch, semibatch, and continuous. 

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