Sodium esters

Of the K ISEs, the best properties are those of the electrode based on the ionophore valinomycin XXII [51,196], marked by high selectivity for potassium with respect to sodium. Esters of phthalic acid (9,10) are used as membrane solvents and it is preferable for the reasons given in section 3.3 if the membrane contains the potassium salt of hydrophobic anion XV or XVI [119, 166]. The ISE containing cyclic polyether XXV is useful for only some applications [183] because its selectivity for potassium with respect to sodium is much smaller than with the valinomycin ISE. 

Tablets, film-coated 382 mg carbenicillin (118 mg indanyl sodium ester) Rx)...

In the commercial utilization of the reduction of esters by sodium, a secondary alcohol such as methyl-isobutylcarbinol is employed. This particular alcohol reacts rather slowly with sodium but rapidly enough with the sodium ester ketal (XXVI) to keep acyloin formation from dominating the reaction. 

When halogen derivatives of benzene and its homologues are treated with ethyl chloroformate and sodium, esters are produced which on hydrolysis yield acids ... 

Aerosol is also a trade name for certain wetting agents, most of which are esters of sodium sulphosuccinic acid. 

Claisen condensation Condensation of an ester with another ester, a ketone or a nitrile in the presence of sodium ethoxide, sodium or sodamidc, with the elimination of an alcohol. The result is the formation of a / -ketonic ester, ketone, or nitrile respectively, e.g. 

The sodium salts of sulphuric acid esters of dextran are used as anticoagulants for the same purposes as heparin. 

C12H12N2O3. White crystals, m.p. 174°C. Prepared by condensing the ethyl ester of phenylethylmalonic acid with urea. It is a more active hypnotic than barbitone. It and its sodium salt - soluble phenobarbitone - are used as sedatives and in treating epilepsy. 

C HgNjOjS. Colourless needles, with iH20. Prepared by reducing diazotized sulphanilic acid with an excess of sodium sulphite. It is a typical hydrazine in its reactions with ketones, and with acetoacetic ester. The latter reaction gives rise to the tartrazine dyestuffs, and is much used commercially. 

SNG Substitute natural gas. soaps Sodium and potassium salts of fatty acids, particularly stearic, palmitic and oleic acids. Animal and vegetable oils and fats, from which soaps are prepared, consist essentially of the glyceryl esters of these acids. In soap manufacture the oil or fat is heated with dilute NaOH (less frequently KOH) solution in large vats. When hydrolysis is complete the soap is salted out , or precipitated from solution by addition of NaCl. The soap is then treated, as required, with perfumes, etc. and made into tablets. 

CgHjClaOj. M.p. 155°C. Used as a selective herbicide. It is made from 2,4,5-trichloro-pheno) and sodium chloroacetate. Ester sprays and combined ester sprays with 2,4-D are available. 2,4,5-T products are of particular value in that they control many woody species, and eradicate perennial weeds such as nettles in pastures. 

The Claisen condensation is initiated by deprotonation of an ester molecule by sodium ethanolate to give a carbanion that is stabilized, mostly by resonance, as an enolate. This carbanion makes a nucleophilic attack at the partially positively charged carbon atom of the e.ster group, leading to the formation of a C-C bond and the elimination ofan ethanolate ion, This Claisen condensation only proceeds in strongly basic conditions with a pH of about 14. 

Reflux Distillation Unit. The apparatus shown in Fig. 38 is a specially designed distillation-unit that can be used for boiling liquids under reflux, followed by distillation. The unit consists of a vertical water-condenser A, the top of which is fused to the side-arm condenser B. The flask C is attached by a cork to A. This apparatus is particularly suitable for the hydrolysis of esters (p. 99) and anilides (p. 109), on a small scale. For example an ester is heated under reflux with sodium hydroxide solution while water is passed through the vertical condenser water is then run out of the vertical condenser and passed through the inclined condenser. The rate of heating is increased and any volatile product will then distil over. 

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