Hydrolysis/hydrogenation

In general, the presence of fatty acid groups in the phosphoHpid molecule permits reactions such as saponification, hydrolysis, hydrogenation, halogenation, sulfonation, phosphorylation, elaidinization, and ozonization (6). 

Several processes often occur in lipids, including oxidation, hydration, dehydration, decarboxylation, esterification, aromatization, hydrolysis, hydrogenation and polymerization. In fact, the chemistry of these materials can be affected, for example, by heat (anthropogenic transformations), humidity, pH, and microbial attacks. 

COMBISULF A process for removing sulfur compounds from the gases from combined-cycle power plants with integrated coal gasification. Carbonyl sulfide is removed by catalytic hydrolysis hydrogen sulfide is removed by selective absorbtion in aqueous MEDA and the sulfur is recovered from both processes by a modified Claus unit. Developed by Krupp Koppers and first operated in Spain in 1996. See PRENFLO. 

In fluorine thermochemistry, two key heat values frequently occur. They are the dissociation energy of difluorine, required for evaluation of fluorine bond energies and the heat of formation of hydrogen fluoride, a product in hydrolysis, hydrogenation, fluorine combustion, or neutralization reactions. These values have been difficult to measure and have changed considerably over the years. A recommended set of values has been reported in recent CODATA bulletins (60) which are collected in Table I together with older values and corrections to update them. 

The domain of hydrides and complex hydrides is reduction of carbonyl functions (in aldehydes, ketones, acids and acid derivatives). With the exception of boranes, which add across carbon-carbon multiple bonds and afford, after hydrolysis, hydrogenated products, isolated carbon-carbon double bonds resist reduction with hydrides and complex hydrides. However, a conjugated double bond may be reduced by some hydrides, as well as a triple bond to the double bond (p. 44). Reductions of other functions vary with the hydride reagents. Examples of applications of hydrides are shown in Procedures 14-24 (pp. 207-210). 

Hydrogen is suggested to come from the spillover from copper.42 The last step is the rapid hydrolysis of the surface methoxy to form the product methanol and restore the surface OH species required for the adsorption of the next CO2. The water-gas shift reaction occurs predominantly on Cu and it is not affected by the presence of Zr02. The suppressed rate of methanol formation over Cu on Zr02 from CO as compared to C02 is ascribed to the absence of water formation, which prevents the more facile release of methoxy by hydrolysis. Hydrogenation of formates detected on Cu on Ti02 was also observed to occur.43... 

Chiral a-methyl-a-amino acids The reaction of phenylacetone with (S)-(-)-l in the presence of NaCN in HOAc affords one (R,S)-diastereomer (2), which is converted to the amide 3 on hydrolysis. Hydrogenation of 3 provides (R)-( + )-2-methy 1-3-phenylalanine (4) in >98% ee. 

The final example of electrolysis is that of water. When water undergoes hydrolysis, hydrogen gas and oxygen gas are the products 2H20 — 2H2 + 02. What is so special about this reaction is how the hydrogen and oxygen can be separated and captured. When the electricity from the external source... 

The chemistry of the hydrolysis/hydrogenation process from (+)-sucrose can be schematized as follows ... 

The hydrolysis, hydrogenation, and oxidation of triacylglycerols—reactions originally discussed in Chapters 12, 15, and 22—are summarized here for your reference. 

In indirect hydrolysis hydrogen chloride is formed which can be further utilized. Direct hydroly.sis is generally carried out discontinuously in mixing tanks. Indirect hydrolysis/alcoholysis can be carried out in a continuous process. The industrial plant used is similar to that for the production of alkoxysilanes (see Section 4.2.2.1). 

Various chemical processes of limonene, which lead to the obtainment of useful chemicals and some analytical methods, are based on these reactions. Many flavor chemicals are synthesized from limonene by reaction with water, sulfur and halogens, or hydrolysis, hydrogenation, boration, oxidation and epoxide formation (Thomas and Bessiere, 1989). Hydroperoxides have also been studied and isolated because of their effect on off-flavor development in products containing citrus oil flavoring agents (Clark et al., 1981 Schieberle et al., 1987). Hydration of d-limonene produces alpha-terpineol, a compound that gives off an undesirable aroma in citrus-flavored products. It is also possible to produce alpha-terpineol and other useful value-added compounds... 

Normal substitution products of potassium N-cyanoanilide and nitriles or esters yield hydantoins by acid hydrolysis. Hydrogen sulfide treatment of 70 gives 2-thiohydantoins in excellent yield.122... 

Caution. Air-free procedures are required for use of potassium hydride, which can explosively generate hydrogen gas upon uncontrolled hydrolysis. Hydrogen gas is generated in the procedure and should not be performed in a sealed flask. 

A mixture of high polyols has been prepared by the simultaneous action of a- or yff-amylase and nickel catalyst on starch (maize) under hydrogen pressure [14]. A syrup with DE 11 and 82% solubles was obtained. Higher DE-level syrups were not obtained by this combined hydrolysis-hydrogenation process because the enzyme was found to be inhibited by leached nickel from the catalyst. 

Hydrolysis, hydrogenation, and the shift reaction take place concurrently at moderate temperatures and atmospheric pressure over an extruded cobalt molybdate catalyst which is sulfided. Space velocities are about 2000 cu ft of tail gas plus reducing gas/hr/cu ft of catalyst. Because of the excessive heat released when sufficient air contacts these catalysts, extraneous air must be excluded from the catalyst at all times, especially during start-up and shutdown. 

Aerobic Palladium-Catalyzed Oxidation of Acrolein to Malonaldehyde Bls-(1,3-dloxan-2-yl]-acetal Followed by Hydrolysis/Hydrogenation to 1,3-Propanediol... 

The sequence consists of a protection step of the aldehyde functional group, an oxidation step of the olefin functional group, and a hydrolysis/hydrogenation step of the two acetal functional groups. 

Figure 11.4 also shows the products formed after hydrolysis/hydrogenation of the various (by-)products. The two main by-products (HDO and MAC) are about 99%. 

In the third step, the reaction mixture obtained from step 2 was subjected to a one-step hydrolysis/hydrogenation. The most promising result was obtained using 7% Rh/Al203, 2 MPa hydrogen and slightly excess water at 90 °C. This condition would give 1.48 kg 1,3-propanediol/g catalyst per hour. After a final distillation step, impurities could only be found at parts per million level. 

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