Dehydration/condensation reaction

The DBSA-system is also applicable for the dithioacetalization of aldehdyes and ketones with 1,2-ethanedithiol to give the corresponding dithioacetals (Scheme 5.4, d). Increasing the reaction temperature decreases the yield of the products. Interestingly, increases in the concentration of the surfactant also decrease the yield of products formed, while shortening the alkyl chain of the surfactant abolishes its catalytic activity. Optical microscopy shows the formation of micelles, which are proposed to form hydrophobic environments and decrease the effective concentration of water and facilitate the dehydrative condensation reactions. 

The main reaction of PCS oxidation by heating in a nitrogen atmosphere involves the formation of Si-O-Si by a dehydration condensation reaction of Si-OH bonds (equation 3). This reaction can be deduced from the fact that the number of Si-OH bonds decreases notably compared with those of other groups. The decrease in Si-H Awlw < 6.2%) and Si-CH3 bonds at >300 °C may be explained by equations 6 and 7. At >400 C, a decrease in Si-H and Si-CH3 bonds was noted for every PCS sample. This finding suggests that Si-CH2-Si bond formation from Si-H and Si-CH3 proceeds by equation 8. 

Strong heating of carboxylic acids forms an acid anhydride through a type of substitution called a dehydration-condensation reaction (Section 14.6), in which two molecules condense into one with loss of water ... 

Esters, like acid anhydrides, form through a dehydration-condensation reaction in this case, it is called an esterification ... 

The monomers of condensation polymers must have two functional groups we can designate such a monomer as A—R—B (where R is the rest of the molecule). Most commonly, the monomers link when an A group on one undergoes a dehydration-condensation reaction with a B group on another ... 

Polymers are extremely large molecules that are made of repeat units called monomers. Addition polymers are formed from unsaturated monomers that commonly link through free-radical reactions. Most condensation polymers are formed by linking two types of monomer through a dehydration-condensation reaction. 

The cellular precursors that form a nucleic acid are nucleoside triphosphates (Figure 15.23A). Dehydration-condensation reactions between them create a chain... 

Esters and acid anhydrides form through dehydration-condensation reactions, and water is the other product. 

Figure 3.1 Interparticle connection between TI02 by dehydration condensation reaction.

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