Use of sodium hydroxide activator

Fluoride ion activator can be replaced by hydroxide ion. To avoid hydrolysis of chlorosilanes, a heterogeneous system consisting of powdered sodium hydroxide in benzene was found to be particularly effective [Eq.(21)]. [20]. 

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The soda, kraft, and sulfite pulping processes are used to prepare full chemical pulps. The soda process, which uses sodium hydroxide as the cooking chemical for delignification purposes, has hugely been superseded by the kraft process, which is characterized by its use of sodium hydroxide and sodium sulfide as active delignification agenls in the chip-cooking phase of the process. 

As mentioned earlier, the magnitude of EOF on PT devices is 10 times lower than that in common microfabrication substrates such as glass, quartz, and PDMS. While the EOF in these popular materials can be raised by chemical or physical modification of the surface (activation by oxygen plasma or sodium hydroxide), similar treatment of PT chips does not yield the same enhancement. The use of sodium hydroxide is not recommended because it attacks the toner surface rapidly (in a few minutes), even at low concentration. However, the low EOF can certainly be an advantage for the analysis of analytes with similar electrophoretic mobilities. One strategy to obtain a simple microdevice but with greater EOF is the fabrication of glass-toner microchips. ... 

The use of sodium hydroxide and sodium carbonate, instead of ammonium hydroxide to obtain aluminnm-doped hematite, led to the production of solids made of hematite containing alnminum. They have different textural and catalytic properties, as well as different resistance against rednction Sodinm hydroxide is the most suitable precipitant to prepare the sohds, leading to the catalyst with the highest activity and selectivity to styrene among the samples stndied. This can be related to its highest intrinsic activity and to its highest specific surface area. 

Dimeihylamine, C2H7N, (CH3)2NH. Colourless, inflammable liquid with an ammoniacal odour, mp -96" C, b.p. 7°C. Occurs naturally in herring brine. Prepared in the laboratory by treating nitrosodimetbyl-aniline with a hot solution of sodium hydroxide. Dimethylamine is largely used in the manufacture of other chemicals. These include the solvents dimethylacetamide and dimethyl-formamide, the rocket propellant unsym-metrical dimethylhydrazine, surface-active agents, herbicides, fungicides and rubber accelerators. 

A more active product is obtained by the following slight modification of the above procedure. Dissolve the succinimide in a slight molar excess of sodium hydroxide solution and add the bromine dissolved in an equal volume of carbon tetrachloride rapidly and with vigorous stirring. A finely crystalline white product is obtained. Filter with suction and dry thoroughly the crude product can be used directly. It may be recrystallised from acetic acid. 

Many methods for the conversion of acid copolymers to ionomers have been described by Du Pont (27,28). The chemistry involved is simple when cations such as sodium or potassium are involved, but conditions must be controlled to obtain uniform products. Solutions of sodium hydroxide or methoxide can be fed to the acid copolymer melt, using a high shear device such as a two-roU mill to achieve uniformity. AH volatile by-products are easily removed during the conversion, which is mn at about 150°C. A continuous process has been described, using two extmders, the first designed to plasticate the feed polymer and mix it rapidly with the metal compound, eg, zinc oxide, at 160°C (28). Acetic acid is pumped into the melt to function as an activator. Volatiles are removed in an extraction-extmder which follows the reactor-extmder, and the anhydrous melt emerges through a die-plate as strands which are cut into pellets. 

In some cases it becomes necessary to use a chemical method of regeneration. Thus, phenolic substances, when adsorbed on activated carbons or polymeric adsorbents, are regenerated using aqueous solutions of sodium hydroxide of an appropriate concentration. 

Freeder, B. G. et al., J. Loss Prev. Process Ind., 1988, 1, 164-168 Accidental contamination of a 90 kg cylinder of ethylene oxide with a little sodium hydroxide solution led to explosive failure of the cylinder over 8 hours later [1], Based on later studies of the kinetics and heat release of the poly condensation reaction, it was estimated that after 8 hours and 1 min, some 12.7% of the oxide had condensed with an increase in temperature from 20 to 100°C. At this point the heat release rate was calculated to be 2.1 MJ/min, and 100 s later the temperature and heat release rate would be 160° and 1.67 MJ/s respectively, with 28% condensation. Complete reaction would have been attained some 16 s later at a temperature of 700°C [2], Precautions designed to prevent explosive polymerisation of ethylene oxide are discussed, including rigid exclusion of acids covalent halides, such as aluminium chloride, iron(III) chloride, tin(IV) chloride basic materials like alkali hydroxides, ammonia, amines, metallic potassium and catalytically active solids such as aluminium oxide, iron oxide, or rust [1] A comparative study of the runaway exothermic polymerisation of ethylene oxide and of propylene oxide by 10 wt% of solutions of sodium hydroxide of various concentrations has been done using ARC. Results below show onset temperatures/corrected adiabatic exotherm/maximum pressure attained and heat of polymerisation for the least (0.125 M) and most (1 M) concentrated alkali solutions used as catalysts. 

Data on the effect of sodium hydroxide were measured by means of an NH3 probe supplied by Orion Research Company which operates in a manner analogous to a pH probe except that a membrane is used through which only the NH3 permeates. Thus the response of the probe is proportional to the activity (or partial pressure) of ammonia. 

There are relatively few reports of phase-transfer catalysed syntheses of phenols from activated haloarenes using quaternary ammonium salts, presumably because of the instability of the ammonium salts under the reaction conditions. A patented procedure for the conversion of, for example, 2,6-dichloropyridine into 6-chloropyrid-2-one (98%) using aqueous sodium hydroxide in the presence of benzyl-triethylammonium chloride at 120-150°C has been filed [32], A possible route to the phenols, however, comes from the observed reaction of phenols with potassium carbonateipotassium hydrogen carbonate to yield the aryl carbonates (80-85%) using the procedure described for the preparation of dialkyl carbonates (3.3.13) [50]. 

Dimethyl-HeptylResorcinol German patent 2,2002,815 (1970). You may use this reference with 3-nonene-2-one (synthesis given above) to make olivetol. This would be easier than producing the 5,6-dimethyl-undec-3-ene-2-one required for dimethyl-heptyl analog, but the loss in activity would be great. Add an excess amount of acetone to 2,3-dimethyloctanol and condense in the presence of sodium hydroxide in benzene at 20-60°. Distill under reduced pressure and reflux in benzene to dehydrate. 

I. Sodium. Probably the best known active hydrogen remover is sodium. When used outside a vacuum system, for instance as sodium wire to dry solvents, the sodium is little more than a support for a skin of sodium hydroxide. Inside a vacuum system, however, one can prepare films of sodium metal and one can prepare really clean sodium which will give a colourless solution of sodium ethoxide (see Section 5.2.1.). The method of making sodium films for the removal of acidic compounds from liquid reagents will be described and also a very much less well-known method involving sodium vapour and colloidal sodium. 

Esters of arenesulfonic acids are prepared by reaction of the corresponding alcohol with the arenesulfonyl chloride in the presence of a basic reagent, which has the function of activating the alcohol and binding the hydrogen chloride. The reaction is often carried out with pyridine, which is used as solvent. In the procedure for tosylates of primary aliphatic alcohols, described in A.l. Vogel, A Textbook of Practical Organic Chemistry, an aqueous solution of sodium hydroxide is used. Esters of primary alcohols are formed more easily than secondary-alkyl esters, while tertiary alcohols cannot be esterified under the usual conditions. 

Electrical Conductance of Aqueous Solutions of Ammonia and Metal Hydroxides. Check the electrical conductance of 1 W solutions of sodium hydroxide, potassium hydroxide, and ammonia. Record the ammeter readings. Arrange the studied alkalies in a series according to their activity. Acquaint yourself with the degree of dissociation and the dissociation constants of acids and bases (see Appendix 1, Tables 9 and 10). Why is the term apparent degree of dissociation used to characterize the dissociation of strong electrolytes ... 

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