Alkali commercially available types

Commercially available P.O.46 types are usually quite transparent. They are employed primarily in packaging printing inks, also in offset and metal deco printing. Publication gravure inks, plastics, especially PVC, LDPE, and elastomers, as well as general industrial paints are suitable media for pigment application. P.O.46 is less solvent resistant than P.R.53 1, but it is faster to alkali and acid. In terms of lightfastness, P.O.46 performs poorly 1/3 and 1/25 SD prints equal only step 1 on the Blue Scale. 

If di(/butylainino)silane, a colorless liquid (bp 50 °C/3 mbar) easily prepared in tetrahydrofuran from commercially available dichlorosilane and rbutylamine in a molar ratio of 1 4, is freated at 0 °C with an equimolar amount of nbutyl lithium in npentane, lithiation of one N-H group as well as cyclization combined with elimination of hydrogen occurs (Eq. 2). Reactions of this type are known from the literature [4, 5] to proceed at higher temperature or in the presence of small amounts of an alkali metal or its hydride. We therefore assume that traces of lithium hydride formed in a side reaction might have catalyzed the formation of compound 4a. 

Once a flame ionization detector has been converted to an alkali flame detector by the addition either of a coated spiral or a pellet, the residue chemist should bear in mind that each detector is a little different from the other and some tinkering with the flow rate and the electrode height (where possible) may be of great benefit. Some alkali flame detectors need an initial conditioning. Some types of pellets, including a commercially available one, are quite susceptible to contamination and the alkali surface has to be cleaned from time to time. The alkali salt itself, of course, should be a high-purity compound. 

Ion-selective membranes attain their permselectivity from ion-exchange, dissolution, or complexation phenomena. Different types of membranes are available for the construction of ion-selective electrodes glass and other solid state rods (crystals), liquid or polymer ion ecchangers, or dissolved ionophores. Many electrodes are commercially available with selec-tivities for different ions, mainly H, alkali metal cations, heavy metal ions, and halides or pseudohalides. Also gas-sensing electrodes may be constructed from an ion-selective electrode and a gas-permeable membrane [182]. Ion selective electrodes and gas-selective electrodes... 

Although in pxinciple associative thickenos could be prepared from any water-soluble polymer to which hydrophobic blocks can be attached, only three types are commercially available at present hydrophobe-modified polyfetl lene oxide), hydrophobe-modified alkali-soluble acrylic polymers, and hydrophobe-modified hydroxyethyl cellulose. However, the literature contains reports on other types, including hydrophobe-modified polyacrylamide [103], hydrophobe-modified hydroxypropyl guar [104], and a hydrophobe-modified cationic cellulose... 

Starting from the corresponding hydroxymethyl-benzocrown, it has been possible to generate the immobilized system (186) by reacting the above precursor with chloromethylated polystyrene (which is available commercially as Merrifield s resin). Typically, systems of this type contain a polystyrene matrix which has been cross-linked with approximately 1-4% p-divinylbenzene. In one study involving (186), a clean resolution of the alkali metal halides was achieved by HPLC using (186) as the solid phase and methanol as eluent (Blasius etal., 1980). In other studies, the divalent alkaline earths were also separated. 

P.R.66, a barium salt, is sold only in the USA. The pigment is also available as an aluminum oxide hydrate precipitate. Its shade is considered a brilliant medium red, which is somewhat yellower than that of the chemically related P.R.67. Commercial types of P.R.66 are very transparent. The pigment is highly sensitive to acid, alkali, and soap. Its fastness to organic solvents is poor, its fastness to overcoating as well. P.R.66 exhibits limited lightfastness. Its main application is in metal deco printing. 

P.R.67, a barium salt, is also available in the form of an aluminum oxide hydrate precipitate. Its shade is bluer compared to the chemically related P.R.66, it is referred to as a bright bluish red. Commercial types are transparent and tinctorially strong. P.R.67 is used especially in metal deco printing. The prints do not tolerate acid, alkali, or soap. They show only limited fastness to organic solvents and to... 

Acyloin-type reactions of esters provide the simplest route to 1-siloxy-l-alkoxycyclopropane [21,22] Eq. (6). The reaction of commercial 3-halopropionate with sodium (or lithium) in refluxing ether in the presence of Me3SiCl can easily be carried out on a one mole scale [21]. Cyclization of optically pure methyl 3-bromo-2-methylpropionate [23], available in both R and S form, gives a cyclopropane, which is enantiomerically pure at C-2, yet is a 1 1 diastereo-meric mixture with respect to its relative configuration at C-l Eq. (7). Reductive silylation of allyl 3-iodopropionate with zinc/copper couple provides a milder alternative to the alkali metal reduction [24] Eq. (8). 

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