Potassium alkylation

Many organometallic compounds are best prepared by this reaction, which involves replacement of a metal in an organometallic compound by another metal. The compound RM can be successfully prepared only when M is above M in the electromotive series, unless some other way is found to shift the equilibrium. That is, RM is usually an unreactive compound and M is a metal more active than M. Most often, RM is R2Hg, since mercury alkyls are easy to prepare and mercury is far down in the electromotive series." Alkyls of Li, Na, K, Be, Mg, Al, Ga, Zn, Cd, Te, Sn, and so on have been prepared this way. An important advantage of this method over 12-36 is that it ensures that the organometallic compound will be prepared free of any possible halide. This method can be used for the isolation of solid sodium and potassium alkyls." If the metals lie too close together in the series, it may not be... 

K Shirahama, M Hayashi, R Matuura. The effects of organic additives on the solubilities and CMC s of potassium alkyl sulfates in water. I. The effects of several hydroxy compounds. Chem Bull Jpn 42 1206-1212, 1969. 

Persson et al. (1991) used diffuse reflection infrared Fourier transform (DRIFT) spectroscopy to study the interactions between galena, pyrite sphalerite and ethyl xanthate. They provided the evidence that the DRIFT spectrum of oxidized galena treated with an aqueous solution of potassium ethyl xanthate is practically identical with that of solid lead (II) ethyl xanthate, which can be formed as the only detectable siuface species on oxidized galena. Dialkyl dixanthogen is formed as the only siuface species in the reaction between oxidized pyrite and aqueous solution of potassium alkyl xanthate. 

Shinoda examined the variation of the CMC of various potassium alkyl malonates, RCH(COOK)2, with the addition of univalent salts. For R = C8, C,2, CM, and C16, the log-log plots of CMC verus counterion concentration produce parallel straight lines of slope -1.12. Criticize or defend the following proposition According to the analysis presented in Example 8.1, the slope of this type of plot equals —(1 — a), meaning that a = —0.12 this negative function apparently means that the micelle binds an excess of counterions and has the opposite charge from that expected. 

The evidence supplied by the method of formation and the occurrence of isomerism as to analogous structures for the thiosulphates and selenosulphates, is amplified by the chemical behaviour of the potassium alkyl selenosulphates, obtained by treatment of potassium selenosulphates with alkyl halides.1 These, on electrolytic reduction and also on oxidation with hydrogen peroxide, yield the corresponding di-selenides (compare the thiosulphates, p. 203). The structure of the selenosulphates therefore involves a selenium atom directly attached to... 

Microstructure with potassium alkyl. With potassium metal 0, 52, 40, 7. 

Because of the ease of removal of its single 4s electron (4.339 eV) and the difficulty of removing a second electron (31.66 eV) potassium is exclusively monovalent in its compounds, which are electrovalent (Some experimental work indicates that the potassium alkyls may be covalent, but even they form conducting solutions in other metal alkyls.)... 

Phosphorus pentaselenide is heated with a mixture of concentrated potassium or sodium hydroxide and potassium alkyl sulphate, the resulting product being fractionated ... 

The Leuckart Thiophenol Reaction allows the preparation of thiophenols and corresponding thioethers from anilines or their corresponding diazonium salts. The first step is the reaction of an aryl diazonium salt with a potassium alkyl xanthate to give an aryl xanthate, which affords an aryl mercaptan upon basic hydrolysis or an aryl thioether upon warming. 

In aqueous solution acidified with acetic aied, disodium tellurapentathionate and potassium alkyl trithiocarbonates combined to form tellurium bis[ulkyl trithiocarbonates]2. 

Sodium and potassium alkyls also polymerize methyl methacrylate to isotactic polymer at low temperatures and in hydrocarbon solvents (233, 211, 212,217). Just as with styrene, stereospecificity increases with decreasing ionic character in the metal-carbon bond and with increasing ability of the metal cation to complex monomer (K < Na< Li). 

Apart from lubricants, spin finishes contain antistatic and spreading and emulsifying agents. These are generally alkyl sulfates, alkylbenzene sulfonates, sulfonated fats and oils and poly(ethylene glycol)-modified fatty acids, fatty acid amides, fatty alcohols, and fatty amines. Potassium alkyl phosphates are extensively used in the production of polyester staple fibers. 

Styrene only forms an isotactic polymer under heterogeneous reaction conditions. This is the case with sodium or potassium alkyls [185,186]. It has been reported that the lithium alkyls produce isotactic polystyrene under homogeneous reaction conditions, but later investigation showed that the presence of lithium hydroxide or oxide is necessary [187]. 

Mechanism of Stereospecific Polymerization of Styrene with Sodium and Potassium Alkyls... 

Carboxylic acids can be characterized by conversion into the p-bromophenacyl derivatives. Alcohols are characterized by conversion into the potassium alkyl xanthates and reaction of these with p-bromophenacyl bromide in acetone to form... 

Molander has published a series of papers demonstrating the utility of potassium alkyl, alkenyl-, alkynyl-, and aryltrifluoroborates in palladium coupling reactions. The crystallinity and air-stability of these trifluoroborate salts make the use of these an interesting alternative to the use of boronic acids or esters. Good yields have been obtained in several related palladium coupling processes, which are most easily classified as Suzuki couplings. The broad applicability of this process is demonstrated by the production of 58 [40], 59 [41], and 60 [42]. 

Reaction 1 appears to result solely in termination. In hydrogenolysis experiments with various chelates we have observed precipitation of lithium hydride in all cases at room temperature. Attempts to generate chelated LiH in situ by adding hydrogen during ethylene polymerization also caused a rapid, irreversible loss of activity. Since there is no evidence that lithium hydride can add to ethylene under moderate polymerization conditions, it is unlikely that any significant chain transfer occurs via this mechanism. Potassium alkyls readily eliminate olefin with the formation of metal hydride, and sodium alkyls do so at elevated temperatures (56). It was noted earlier that chelation of lithium alkyls makes them more like sodium or potassium compounds, so it is quite probable that some termination occurs by eliminating LiH. It is conceivable that this could be a chain transfer mechanism with more reactive monomers than ethylene because addition to lithium hydride would be more favorable. 

Dithiodi(thioformates [bi(ethyl xanthates) [) 800 The potassium alkyl xanthate is dissolved in water and cooled in ice while a rapid stream of air containing 5-10 % of chlorine is led through until treating a sample of the liquid with copper sulfate no longer gives a precipitate of copper xanthate. The precipitate or oil produced is separated, taken up in ether, dried, recovered, and distilled. 

Zoharphos A-3. [Zohar Detergent Factory] Potassium alkyl ether pho hate andstat for syn. fibers. 

Table 4.8 Particle size averages of polystyrene latex particles prqtated widi equal micellar concentrations of potassium alkyl carboxylates [57] ...

Glucopyranosyl xanthates of general formula (27) have been prepared by reaction of 2,3,4,6-tetra-0-acetyl-o -D-glucopyranosyl chloride with potassium alkyl xanthates o.r.d., c.d., u.v., and n.m.r. spectra of the products were examined and the effect of solvents on the Cotton effect curve was studied. The thermal decomposition of the dixanthates (28) and (29), prepared... 

The reaction of sodium or triethylamlne salts of disubstituted di-thio or thiolcarbamic acid or the potassium alkyl dithiocarbonates with substltuted-thiophthallmides in isopropyl alcohol at 25-30 afforded a novel synthesis for the titled compounds (63). 

The same pathway was proposed for the reaction of N-(cyclohexylthio)-phthallmlde with potassium alkyl dithiocarbonate. The titled com- pounds exhibited moderate activity as herbicides. 

---