Hydrolysis above

Hydrated chlorides that are susceptible to hydrolysis above room temperature can often be dehydrated by treating them with SOCI2 under reflux ... 

Measurement of the stability constants of plutonium complexes is hampered by difficulties of maintaining a particular oxidation state. Formation of complexes of Pu+3, except in very acid solutions, is accompanied and often obscured by complexation catalyzed oxidation to Pu+lt. Study of complexation of Pu+lt is often confused by competition with hydrolysis above pH 1-2. 

When not complexed, lanthanide ions have a high affinity for bone in vivo because they act as calcium ion mimics. Because the lanthanides undergo hydrolysis above a pH of 4, they readily form radiocolloids when not complexed, and are then taken up by the liver. This bone and liver uptake results in non-specific radiation doses to non-target (normal) tissues and organs and is undesirable.91 The polyaminocarboxylate class of ligands are considered to be the optimal choice for the basis of BFCAs for the+3 metal cations, including the lanthanides. It is essential that the... 

Another type of reaction was seen for dalvastatin (8.151), a prodrug that bears an unsaturated side chain. The hydrolysis of dalvastatin to the active acid competes with epimerization at C(6), the rate of the reaction being independent of pH above pH 2 [192], The mechanism is believed to be one of heterolytic cleavage of the C(6)-0 bond to generate a C-centered carbonium ion stabilized by the extended conjugated system characteristic of this compound. In the pH range 2 - 7, the rate of epimerization was found to be ca. 100 times faster than hydrolysis. Above pH 7, base catalysis accelerates hydrolysis, the rate of which increases ca. 100-fold between pH 7 and 9. These facts serve only to complicate the design of HMG-CoA reductase inhibitors and the interpretation of their pharmacokinetic behavior. 

The aqueous filtrate obtained from the acylase-mediated hydrolysis above was acidified with 1M HC1 to pH 2.4. A solid formed, which was filtered and washed with H20 and dried in vacuo affording (R)-82 as yellow crystals yield 1.38 g (46%) mp 203-204 °C [a]D25 —53.2 (c 0.74, AcOH). 

Brines containing 33-34% MgCl2 may be derived as a by-product from the potassium industry or produced by dissolving magnesium-bearing minerals in hydrochloric acid. Naturally occurring dilute brines are concentrated by solar evaporation or conventional dehydration processes. To avoid hydrolysis above 200°C, the final dehydration is performed in an atmosphere of hydrogen chloride. 

Between pH 2 and 7, the rate of hydrolysis of this thiol ester is independent of pH. At pH 5 the rate is proportional to the concentration of acetate ion [AcCT] in the solution and the reaction goes twice as fast in D2O as in H2O. Suggest a mechanism for the pH-independent hydrolysis. Above pH 7, the rate increases with pH. What kind of change is this ... 

Homocitrulline elutes from most analyzer columns just prior to valine. Alternatively, the unreacted lysines can be converted under denaturing conditions to other acid-stable derivatives (homoarginine, methyl-lysines, carboxymethyllysines) which can be quantitated after acid hydrolysis (above and 2.12). The homocitrulline content can then be assumed to be the difference between the total lysine content and the content of the acid-stable derivative. Alkaline hydrolysis of carbamylated proteins gives quantitative conversion of homocitrulline to lysine (Stark and Smyth 1963), and this can be used to check the homocitrulline content of the protein in which the other lysines have been converted to another derivative that does not give lysine by alkaline hydrolysis (see also 3.I.2.I.). 

Comapred to the numerous options for silica, there are relatively few precursors available for the deposition of high quality alumina. The most common precursor is aluminum trichloride (AICI3), which undergoes hydrolysis above 1050 C by the reac-tion ... 

Succinylation of amino groups results in the formation of N-succi-nyl (Fig. 1(1)) bonds, which are very stable in neutral as well as weakly acidic and alkaline conditions. In contrast to this, 0-succi-nyltyrosine residues, which are readily formed under the conditions of amino group succinylation, are not stable, owing to a rapid intramolecular hydrolysis above pH 5 (Fig. 1(2)). Serine and threonine hydroxyl groups are not easily acylated in aqueous solutions, because they are weak nucleophiles. However, their succinyl derivatives are rather stable and do not hydrolyze as spontaneously as Osuccinyltyr-osine, but they can be cleaved by treatment with hydroxylamine [24], Acylation of histidine and cysteine residues yields products that are highly unstable and are readily hydrolyzed in aqueous solution [23]. 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hazardous polymerization will not occur may form small amounts of phosgene due to unusual exposure to light in the presence of air degrades slowly when exposed to air reacts with chemically active metals, strong caustics, and fuming sulfuric acid attacks most plastics and rubber reaction with water can cause appreciable hydrolysis above 110°C (230°F), hydrolysis and oxidation become rapid not an inert solvent FP (NA) LFL/UFL (NA) AT (NA) HC (NA) HF (-195.0 kJ/mol liquid at 25°C). 

In practise the hydrolysis is carried out at 170-180 C (5 bar pressure) for 30 minutes in a plug flow type of continuous reactor. Hydrolysis above 180 C results in poor colours and introduces corrosion problems. It is recommended that neutralisation and hydrolysis are carried out at different temperatures. By keeping neutralisation temperatures below 100 C, paste viscosities are depressed and this permits a higher solids charge to the hydrolyser. 

PVAl with the degrees of hydrolysis above 87% are not soluble at all... 

To build the necessary compounds such as proteins and DNAs, you have to combine smaller units by condensation reactions. Condensation reactions are typically accompanied by positive free energy changes, though of relatively small magnitudes. Condensation is opposite of the hydrolysis above and is accompanied by the formation of a more rigid entity and hence by the decrease in randomness (entropy). That means that such a reaction would not proceed without an added (negative) energy. 

Cupric azide Cu(N3)2 forms several basic salts that are described in Table 4.8 [15]. Basic cupric azides are insoluble in water and undergo hydrolysis above 80 °C. They are soluble in acids and bases [5, 15],... 

Hydrolytic stability and pH have to be considered when selecting a cationic monomer. Cationic acrylate esters are susceptible to base hydrolysis above pH 6, resulting in the loss of cationic charge on the polymer. The rate of hydrolysis is concentration and temperature dependent. In contrasL cationic acrylamide copolymers containing amide monomers such as APTAC and MAPTAC are reasonably stable up to a pH of 9-10. Acrylamide/MAPTAC copolymers and... 

The introduction of methylene groups between the sulfonic functions and the benzene ring prevents the hydrolysis above 150°C. ... 

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