NaOH-CsOH

A detailed study of the transmetaUation in the Suzuki-Miyaura reaction by the group of Amatore and Jutand shows that hydroxide [261] and fluoride anions [262] form the key trans-[ArPdX(L)2] complexes that react with the boronic acid in a rate-determining transmetaUation. In addition, the anions promote the reductive elimination. Conversely, the anions disfavor the reaction by formation of nonreactive anionic [Ar B(OH)3 X ] (7t=l-3). Countercations M" " (Na" ", K" ", and Cs+) of anionic bases in the palladium-catalyzed Suzuki-Miyaura reactions decelerate the transmetaUation step in the following decreasing reactivity order nBu4NOH > KOH > CsOH > NaOH this is due to the complexation of the hydroxy ligand in [ArPd(OH)(PPh3)2] by M+[263]. 

Polymerization of BPA and 1,6-dibromohexane at 88°C for 3 hours. The amounts of reactants and solvent were the same as described in "Experimental" section. Excess (20 mole %) LiOH, CsOH, NaOH and KOH were used. 

Anionic Polymerization of Cyclic Siloxanes. The anionic polymerization of cyclosiloxanes can be performed in the presence of a wide variety of strong bases such as hydroxides, alcoholates, or silanolates of alkaH metals (59,68). Commercially, the most important catalyst is potassium silanolate. The activity of the alkaH metal hydroxides increases in the foUowing sequence LiOH < NaOH < KOH < CsOH, which is also the order in which the degree of ionization of thein hydroxides increases (90). Another important class of catalysts is tetraalkyl ammonium, phosphonium hydroxides, and silanolates (91—93). These catalysts undergo thermal degradation when the polymer is heated above the temperature requited (typically >150°C) to decompose the catalyst, giving volatile products and the neutral, thermally stable polymer. 

Tables 1 and 2 clearly show that the use of such alkali metal hydroxides as KOH, CsOH, and mixtures of KOH/NaOH allowed the reaction to proceed to a high DMAPN conversion with a very high selectivity for the primary amine. These results suggest that the highest selectivity in the hydrogenation of DMAPN to DMAPA is obtained with KOH, and mixtures of KOH/NaOH.

Another important feature of this reaction is the low pressure at which the reaction proceeds. Unlike hexamethylenediamine or other amines produced with this process, the hydrogenation of DMAPN to DMAPA proceeds at veiy low pressures. High catalyst activity and high selectivity are obtained at 100 psig for NaOH, KOH, RbOH and blended NaOH/KOH. Testing with CsOH and LiOH was only conducted at 500 psig, and these tests were not repeated at 100 PSIG for CsOH and LiOH due to time constraints. 

Alkali metal (Group IA) hydroxides (LiOH, NaOH, KOH, RbOH and CsOH) Calcium, strontium, and barium hydroxides... 

V,Af-Dimethylaniline A A,A, AT-Tetramethyl-p-phenylenediamine Cyclic amines 4,4 -Bipyridyl Quinoline Pyridine A-oxide Pyridinium chloride Hydroxides CsOH LiOH NaOH Triton B6 Alkylamines Ammonia Methylamine Ethylamine Propylamine Butylamine Decylamine Dodecylamine Tridecylamine Tetradecylamine Pentadecylamine Hexadecylamine Heptadecylamine Octadecylamine Tributylamine Miscellaneous Ammonium acetate Hydrazine Potassium formate Guanidine... 

Schulman (51) on Li, Na, and K stearates. The NH4OH and LiOH curves are similar in shape to the HC1 curve. The CsOH, RbOH, KOH, and NaOH curves are highly expanded, with lower collapse pressures. The NaOH curve seems to exhibit unusually pronounced solubility effects at low surface areas. At areas greater than 50 sq. A. per molecule, the surface pressures for the soaps are still substantial (greater than 5 dynes per cm.), while they fall to near zero for the unionized fatty acid. 

Zeolite rho was prepared from aluminosilicate hydrogels containing sodium and cesium cations. The procedure is entirely comparable with the synthesis of faujasite except for substitution of CsOH for about 10% of the NaOH in the faujasite synthesis gel. Alumina trihydrate (Alcoa C-33 grade) was dissolved in 50% NaOH solution at 100°. After cooling to ambient temperature, the required amount of CsOH solution was added, and the resulting liquor was blended into 30% silica sol (duPont Ludox LS-30) with vigorous mixing. After 3-7 days incubation at 25°, the synthesis gel was held at constant temperature, 80, 90, or 100°, until crystals formed maximum crystallinity was usually achieved in 2-4 days. 

Due to economic considera-j V J tions NaOH and KOH are the only two common strong bases with group 1A metal ions. The others (LiOH, RbOH, CsOH) are equally strong bases. 

Table 1. Yields in the aldol condensations leading to macrocyclic dichalcones 4 with the bases NaOH and CsOH [24]...

The rate of compound 2 formation increased dramatically on going from LiOH to NaOH and further to KOH and LiOH-CsF. However, vinylation in the presence of LiOH did not occur at all, but the reaction proceeded quite fast with NaOH, KOH and CsOH. The effect of NaOH-CsF turned out to be unexpected the selectivity of pyrrole 2 formation increased and the vinylation was suppressed. 

All the hydroxides of the Group 1A elements (LiOH, NaOH, KOH, RbOH, and CsOH) are strong bases, but only NaOH and KOH are common laboratory reagents because the lithium, rubidium, and cesium compounds are expensive. The alkaline earth (Group 2A) hydroxides—Ca(OH)2, Ba(OH)2, and Sr(OH)2—are also strong bases. For these compounds 2 moles of hydroxide ion is produced for every 1 mole of metal hydroxide dissolved in aqueous solution. 

The compound LiOH is called lithium hydroxide. The othex aikali metals form hydroxides with similar formulas NaOH, KOH, RbOH, and CsOH. These hydroxides are all strongly basic substances. 

St. Pierre and Price [23] have also shown that anhydrous KOH is an interesting initiator of epoxide polymerization. Anhydrous RbOH and CsOH were also effective but, interestingly, NaOH and LiOH were not. 

The temperatures and enthalpies of the polymorphic transitions and melting of CsOH(cr) are from the work of Reshetnikov and Baranskaya (10). These data were determined thermographlcally with 1.575 kcal mol for NaOH(cr) as a standard. 

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