Catalyst sulfuric acid

There are environmental concerns over the use of HE catalyst. The refining industry has taken steps to reduce the likelihood of an accidental release and to minimizp the environmental impact in the event of a release. As a result of these environmental concerns, most new units use sulfuric acid catalysts. 

Koch Ro- ction. C-6-neoacids are readily available from amyl alcohols by the Koch reaction. Greater than 95% 2,2-dimethylbutyric acid [595-37-9] was obtained from 2-methyl-1-butene at 304 kPa (3 atm) CO and 35°C for 1 h with cupric oxide and sulfuric acid catalyst (31). Likewise,... 

Catalysts. Commercial sulfuric acid catalysts typically consist of vanadium and potassium salts supported on sUica, usually diatomaceous earth (see Diatomite). Catalyst peUets are available in various formulations, shapes, and sizes depending on the manufacturer and the particular converter pass in which they are to be used. A detailed discussion of oxidation catalysts for sulfuric acid production is available (107). 

Cellulose valerates have been synthesized by conventional methods using valeric anhydride and sulfuric acid catalyst (25,26). Alternatively, the cellulose is activated by soaking in water, which is then displaced by methylene chloride or valeric acid the temperature is maintained at <38° C to minimize degradation. 

Solution Process. With the exception of fibrous triacetate, practically all cellulose acetate is manufactured by a solution process using sulfuric acid catalyst with acetic anhydride in an acetic acid solvent. An excellent description of this process is given (85). In the process (Fig. 8), cellulose (ca 400 kg) is treated with ca 1200 kg acetic anhydride in 1600 kg acetic acid solvent and 28—40 kg sulfuric acid (7—10% based on cellulose) as catalyst. During the exothermic reaction, the temperature is controlled at 40—45°C to minimize cellulose degradation. After the reaction solution becomes clear and fiber-free and the desired viscosity has been achieved, sufficient aqueous acetic acid (60—70% acid) is added to destroy the excess anhydride and provide 10—15% free water for hydrolysis. At this point, the sulfuric acid catalyst may be partially neutralized with calcium, magnesium, or sodium salts for better control of product molecular weight. 

Direct reaction of formaldehyde cyanohydrin and ethylenediamine in the presence of a sulfuric acid catalyst gives ethylenediarninetetraacetonitrile [5766-67-6], hydrolysis of which leads to ethylenediarninetetraacetic acid [60-00-4] (EDTA), a widely used sequestering agent (26). 

With these kinetic data and a knowledge of the reactor configuration, the development of a computer simulation model of the esterification reaction is iavaluable for optimising esterification reaction operation (25—28). However, all esterification reactions do not necessarily permit straightforward mathematical treatment. In a study of the esterification of 2,3-butanediol and acetic acid usiag sulfuric acid catalyst, it was found that the reaction occurs through two pairs of consecutive reversible reactions of approximately equal speeds. These reactions do not conform to any simple first-, second-, or third-order equation, even ia the early stages (29). 

Similar studies have been performed on the formation of mono -butyl phthalate at 80—150°C with sulfuric acid catalyst (31). The reaction of phthahc anhydride with mono -butyl phthalate to afford di -butyl phthalate is complete ia 10 min at 100°C with 1 wt % catalyst. 

Continuous esterification of acetic acid in an excess of -butyl alcohol with sulfuric acid catalyst using a four-plate single bubblecap column with reboiler has been studied (55). The rate constant and the theoretical extent of reaction were calculated for each plate, based on plate composition and on the total incoming material to the plate. Good agreement with the analytical data was obtained. 

Esterification reactions can be catalyzed by the ionic liquid 1-butylpyridinium chloride-aluminium chloride ([BP]C1/A1C13 (X(A1C13) = 0.33) [34, 35]. Deng and coworkers found that higher yields were obtained than in similar reactions with a sulfuric acid catalyst. 

The atom economy for this process is 86.5% (100 X 116/134), which is reasonable. To calculate the E-factor and EMY further information is needed. From published literature (Vogel s Practical Organic Chemistry ), a standard procedure is to mix butanol (37 g) with glacial acetic acid (60 g), and a small amount of sulfuric acid catalyst (ignored in all calculations). Following completion of the reaction the mixture is added to water (250 g). The crude ester is washed further with water (100 g), then saturated sodium bicarbonate solution (25 g) and finally water (25 g). After drying over 5 g of anhydrous sodium sulfate the crude ester is distilled to give product (40 g) in a yield of 69%. 

The production of biodiesel from low quality oils such as animal fats, greases, and tropical oils is challenging due to the presence of undesirable components especially FFA and water. A pre-treatment step is required when using such high fatty-acid feedstock. Generally, this esterification pre-treatment employs liquid sulfuric acid catalyst which must subsequently be neutralized and either disposed of or recycled. However, requirement of high temperature, high molar ratio of alcohol to FFA, separation of the catalyst, enviromnental and corrosion related problems make its use costly for biodiesel production. 

The hydration of propylene with sulfuric acid catalyst in high-temperature water was investigated using a flow reaction system.31 The major product is isopropanol. A biopolymer-metal complex, wool-supported palladium-iron complex (wool-Pd-Fe), has been found to be a highly active catalyst for the hydration of some alkenes to the corresponding alcohols. The yield is greatly affected by the Pd/Fe molar ratio in the wool-Pd-Fe complex catalyst and the catalyst can be reused several times without remarkable change in the catalytic activity.32... 

In order to freeze the equilibrium during distillation, it is imperative that the sulfuric acid catalyst be previously neutralized by sodium acetate hence it is important that the small quantities of sulfuric acid and sodium acetate be measured carefully. 

Data for the formation of glycol (C) from ethylene oxide (A) and water (B) with sulfuric acid catalyst at 55°C are cited by Fogler (110, 1992). 

Figure 4.11. Alkylation unit (sulfuric acid catalyst).

TATP is very sensitive to impurities. The primary destabilizing impurity present in the TATP synthesis is the residual sulfuric acid catalyst. TATP purity can be related to the extent of which the acid is removed or washed out of the final product. The TATP produced by the author is made in an exceedingly meticulous fashion and is as free of impurities as it can physically be. The common criminal or terrorist cannot be counted on to be as careful in his or her TATP preparations. 

This process allows the purification of glycols without the difficulties of salt separation because the manufacturing procedure is done in two discrete steps with ethylene oxide distillation prior to hydrolysis. The hydration step is either uncatalyzed at high temperatures and pressures or utilizes an acid catalyst. A U.S. Industrial Chemicals, Inc. process uses a sulfuric acid catalyst at moderate temperatures producing an aqueous solution of glycol-containing acid (9). This process requires an additional step in the purification to remove the catalyst. 

Such reactions can take place predominantly in either the continuous or disperse phase or in both phases or mainly at the interface. Mutual solubilities, distribution coefficients, and the amount of interfadal surface are factors that determine the overall rate of conversion. Stirred tanks with power inputs of 5-10 HP/1000 gal or extraction-type equipment of various kinds are used to enhance mass transfer. Horizontal TFRs usually are impractical unless sufficiently stable emulsions can be formed, but mixing baffles at intervals are helpful if there are strong reasons for using such equipment. Multistage stirred chambers in a single shell are used for example in butene-isobutane alkylation with sulfuric acid catalyst. Other liquid-liquid processes listed in Table 17.1 are numbers 8, 27, 45, 78, and 90. 

Most commercial preparations of cellulose esters still follow, basically, the methods described by Franchimom and Miles—esterification with sulfuric acid catalyst followed by hydrolysis. The principal steps in this process are shown in Fig. I. 

The shredded pulp is treated with glacial acetic acid which may contain part or all of the sulfuric acid catalyst. This prctreatmenl" swells the cellulose libers and increases the accessibility of the acetylatine agent. Ratios of acetic acid to cellulose may be I I to 3 1 and the treatment time may vary from one-half to several hours, depending upon temperature. 

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