Hydration products sequence formed

In [27-29], hydrothermal, mechanochemical and solid-phase syntheses of calcium silicate from anhydrous and hydrated oxides were compared. Initial components were taken at Ca/Si ratio equal to 0.8 1.0 1.2. According to X-ray analysis, the interaction in the mixtures of anhydrous oxides under mechanical activation is not completed. The product being formed is X-ray amorphous. When heated at 600-800 C, it is crystallized in the form of a -Ca2Si04 (Fig. 3.6a). At higher temperatures, Ca3Si207 is formed P-CaSiOj is crystallized at 860 C. The observed sequence of stages is similar to those observed in solid-phase synthesis of wollastonite. The amount of p-CaSiOj at 900°C does not exhibit any substantial dependence on the initial fractions of the reagents. 

Ferrite forms the same sequence of hydration products as C3A in the presence of gypsum, but the reactions are slower and produce less heat. With an increasing... 

This arrangement of subgroups is due to the hypothetical biosynthetic sequence. It assumes that precursors for these alkaloids are the Af-methylphth-alideisoquinolinium salts, whose presence in plants is well documented. Enol lactones may be the initial degradation products formed in a Hofmann-type jft-elimination process. They could be hydrated to the keto acids and in the next step oxidated in air to the diketo acids. Diketo adds may undergo further oxidative cleavage to yield simple alkaloids of the fumariflorine (87) type 85,86), which seem to be the final products of the metabolism of phthalideiso-quinoline alkaloids. 

The commercially available form of Aspartame is hemihydrate Form II, which transforms into hemihydrate Form I when milled, and a 2.5-hydrate species is also known [57,58]. XRPD has been used to study the desolvation and ultimate decomposition of the various hydrates. When heated to 150°C, both hemihydrate forms dehydrate into the same anhydrous phase, which then cyclizes into 3-(carboxymethyl)-6-benzyl-2, 5-dioxopiperazine if heated to 200°C. The 2.5-hydrate was shown to dehydrate into hemihydrate Form II when heated to 70°C, and this product was then shown to undergo the same decomposition sequence as directly crystallized hemihydrate Form II. 

The discrepancies between calculated and experimental curves at 225 nm (Fig. 33) reflect a breakdown in the assumptions made in the computational methods.138 Not only are the reactivities of sites increased by the presence of a product at the adjoining site, but there are major amounts of products other than dimers or hydrates formed. There is evidence138 that the hydrate is rapidly converted to another photoproduct at 225 nm. The dimer reversal cross sections may not be the same in poly U as in UpU, and dimer-rich sequences are also produced. 

The reaction is of the first order with respect to [W(CN)g] , formaldehyde, and OH" concentrations, and product [W(CN)g] ions have no retarding effect upon the reaction rate (107). Since the formaldehyde is in the hydrated form, the OH" concentration dependence should involve a prior neutralization step in the mechanistic sequence of... 

Triacylglycerols can be mobilized by the hydrolytic action of lipases that are under hormonal control. Fatty acids are activated to acyl CoAs, transported across the inner mitochondrial membrane by carnitine, and degraded in the mitochondrial matrix by a recurring sequence of four reactions oxidation by FAD, hydration, oxidation by NAD+, and thiolysis by CoA. The FADH2 and NADH formed in the oxidation steps transfer their electrons to O2 by means of the respiratory chain, whereas the acetyl CoA formed in the thiolysis step normally enters the citric acid cycle by condensing with oxaloacetate. Mammals are unable to convert fatty acids into glucose, because they lack a pathway for the net production of oxaloacetate, pyruvate, or other gluconeogenic intermediates from acetyl CoA. 

Alkenes can be hydrated to form alcohols by (1) hydroboration followed by oxidation with alkaline hydrogen peroxide and (2) acid-catalyzed hydration. Compare the product formed from each alkene by sequence (1) with those formed from (2). 

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