Sodium chloride esters

The above simple experiments illustrate the more important properties of aliphatic acid chlorides. For characterisation, the general procedure is to hydrolyse the acid chloride by warming with dilute alkali solution, neutralise the resulting solution with dilute hydrochloric acid (phenol-phthalein), and evaporate to dryness on a water bath. The mixture of the sodium salt of the acid and sodium chloride thus obtained may be employed for the preparation of solid esters as detailed under Aliphatic Acids, Section 111,85. The anilide or p-toluidide may be prepared directly from the acid chloride (see (iii) above and Section III,85,i). 

This product is sufficiently pure for the preparation of phenylacetic acid and its ethyl ester, but it contains some benzyl tso-cyanide and usually develops an appreciable colour on standing. The following procedure removes the iso-cyanide and gives a stable water-white compound. Shake the once-distilled benzyl cyanide vigorously for 5 minutes with an equal volume of warm (60°) 60 per cent, sulphuric acid (prepared by adding 55 ml. of concentrated sulphuric acid to 100 ml. of water). Separate the benzyl cyanide, wash it with an equal volume of sa+urated sodium bicarbonate solution and then with an equal volume of half-saturated sodium chloride solution- Dry with anhydrous magnesium sulphate and distil under reduced pressure. The loss in washing is very small (compare n-Butyl Cyanide, Section 111,113, in which concentrated hydrochloric acid is employed). 

When It IS necessary to prepare secondary alkyl halides with assurance that no trace of rearrangement accompanies their formation the corresponding alcohol is first converted to its p toluenesulfonate ester and this ester is then allowed to react with sodium chloride bromide or iodide as described m Section 8 14... 

The second process to finish phthalocyanine, which is more important for P-copper phthalocyanine, involves grinding the dry or aqueous form in a ball mill or a kneader (64). Agents such as sodium chloride, which have to be removed by boiling with water after the grinding, are used. Solvents like aromatic hydrocarbons, xylene, nitrobenzene or chlorobenzene, alcohols, ketones, or esters can be used (1). In the absence of a solvent, the cmde P-phthalocyanine is converted to the a-form (57,65) and has to be treated with a solvent to regain the P-modification. The aggregate stmcture also has an impact on the dispersion behavior of a- and P-copper phthalocyanine pigments (66). 

Acid chloride, which is of similar character to the foregoing process, but gives rise in some cases to the simultaneous formation of two isomeric compounds, a fact which at one time threw considerable doubt on the ketonic chaiacter of acetn-acetic ester. Thus chlorofoimic ester and sodium acctoacetir ester produce the following two derivatives, of which the secrjnd predominates ... 

Anschutz 1 treated aceto-salicylic chloride with sodium-malonic ester, with the formation of ethyl acetate and y3-hydroxy-coumarin-alpha-car-hoxylic ethyl ester—... 

The reaction mixture Is stirred overnight at room temperature and filtered to remove the sodium chloride. The filtrate is stripped in vacuo and the crude ester (literature reports MP 48°C) is dissolved in 150 ml of ethanol 2B grams (0.70 mol of sodium hydroxide in 90 ml of water Is added and the solution is refluxed for 2 hours. After removal of the ethanol in vacuo the residue Is dissolved in water and extracted twice with ether. Dissolved ether Is removed from the aqueous solution in vacuo and it Is acidified to pH 2 with concentrated hydrochloric acid. 

Impurities consist of unreacted material, including alkanes and internal or branched alkenes, and other material which can be detected in the neutral oil fraction of AOS. Examination of this fraction also indicates the amount of unhydrolyzed material (sulfonate esters and sultones) and byproducts (secondary alcohols, unsaturated and 2-chloro-y-sultones) in the sample. Salt calculations are made to determine inorganic sulfates and sodium chloride. Determinations for alkalinity, color, and water are required to meet product... 

Reistma et al. [2] establish the positive influence of NaCl on the deesterification of ester groups of amidated pectins with ammonium hydroxide, without discussing the mechanism of the catalytic action of the sodium chloride. 

The substrate commonly employed is 0.5-1.0% of pectin in 50-200 mM sodium chloride (20-60 ml) at a suitable pH and 30°. The pectinesterase activity is mostly expressed in micro-equivalents of ester hydrolyzed per minute at the given pH and temperature. The use of a variety of units of activity, which was complicated and prevented ready comparison of the results of various authors, has now been discontinued. 

Lineweaver and Ballou49 have proposed a pectinesterase unit ( PE. u. ) for expressing PM activity. One such unit is equivalent to 1/930 PMU under the same experimental conditions or the quantity of enzyme that, at 30° and optimum pH, will catalyze the hydrolysis of pectin at an initial rate of one milliequivalent ester bonds per minute in a standard substrate (0.5% citrus pectin containing 8-11% methoxyl) and 0.15 M sodium chloride. The use of the latter unit is unfortunate since the values obtained for the activity in ordinary plant materials are obtained in the third decimal place and because the experimental conditions are so... 

In washing the layer of ethyl phenylacetate with sodium carbonate it is sometimes advisable to add a certain amount of sodium chloride so that the ester will separate more readily. 

This procedure has been used successfully for many years in the preparation of ethyl laurate, caprylate, and myristate by the alcoholysis of cocoanut oil (1 kg.) in ethanol (1900 g.) with hydrogen chloride (50 g.) as a catalyst.3 The method differs slightly from the one described above. The alcoholysis is complete after fifteen or twenty hours, and the solution is then neutralized to methyl orange with barium carbonate. The mixture is added to an equal volume of a saturated sodium chloride solution, whereupon 1100-1300 g. of the mixture of crude ethyl esters separates. This mixture of esters is washed with water and fractionated as described above. The yields are approximately 50 g. of ethyl caprylate, 350 g. of ethyl laurate, and 60 g. of ethyl myristate from 1000 g. of cocoanut oil. 

Perlmutter used an oxymercuration/demercuration of a y-hydroxy alkene as the key transformation in an enantioselective synthesis of the C(8 ) epimeric smaller fragment of lb (and many more pamamycin homologs cf. Fig. 1) [36]. Preparation of substrate 164 for the crucial cyclization event commenced with silylation and reduction of hydroxy ester 158 (85-89% ee) [37] to give aldehyde 159, which was converted to alkenal 162 by (Z)-selective olefination with ylide 160 (dr=89 l 1) and another diisobutylaluminum hydride reduction (Scheme 22). An Oppolzer aldol reaction with boron enolate 163 then provided 164 as the major product. Upon successive treatment of 164 with mercury(II) acetate and sodium chloride, organomercurial compound 165 and a second minor diastereomer (dr=6 l) were formed, which could be easily separated. Reductive demercuration, hydrolytic cleavage of the chiral auxiliary, methyl ester formation, and desilylation eventually led to 166, the C(8 ) epimer of the... 

If the oxidation is slower than the decomposition, oxygen may affect the nature of reaction products. Thus, treating p-nitrocumyl chloride with sodium malonate ester in a flow of pure dry nitrogen yields a product of C-alkylation (route a in Scheme 5.12) the yield is 90%. Oxygen completely inhibits the C-alkylation, and the reaction gives p-nitrocumyl alcohol in the same yield (route b in Scheme 5.12) (Kornblum et al. 1968). 

In this reaction, esters of fatty acids are hydrolysed and the soap obtained remains In coUoldal form. It Is precipitated from the solution by adding sodium chloride. The solution left after removing the soap contains glycerol, which can be recovered by fractional distillation. Only sodium and potassium soaps are soluble in water and are used for cleaning purposes. Generally potassium soaps are soft to the skin than sodium soaps. These can be prepared by using potassium hydroxide solution m place of sodium hydroxide. 

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