Nature and constitution of Shellac: IV. A study of the saponification number

Whitmore, Willet F.; Weinberger, Harold; Gardner, Wm. Howlett

doi:10.1021/ac50077a022

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…The submicroscopic spaces between the enmeshed fibers would account for the porous structure and the ability of solvents to more or less completely leave a drying film. The complex (probably both ring and chain) structure of shellac molecules of relative small molecular weight (21) may account for the unusual protective properties of films of this resin.…”

Section: Bloomingmentioning

confidence: 97%

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Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2

Gardner¹

1931

Ind. Eng. Chem.

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INDUSTRIAL AND ENGINEERING CHEMISTRYYol. 23, No. 12 experiments will be necessary to determine under what conditions the use of ultra-violet glass in winter in New York or Chicago will be of value in protecting against rickets.Summary 1-This study shows that when albino rats are exposed to Chicago sunshine at the street level during the month of February and behind commercial ultra-violet glass or ordinary glass, they are not protected against rickets; whereas similar rats under similar conditions during a March-April period are fully protected against rickets when behind the ultra-violet glass, but not protected when behind ordinary glass.2-Spectrophotographs comparing the transmitting efficiency of the ultra-violet glasses used in the previously mentioned rat experiments, with a variety of other samples of commercial ultra-violet glass show that in the region 3000 to 3100 Á. the transmission is between about 30 per cent for the poorest to about 52 per cent for the best of the glasses which were used; and that, therefore, there are among these glasses some which are average and representative of commercial ultra-violet glass.3-These results indicate that there is a critical difference between the rickets-preventing efficiency of February sunshine and March-April sunshine behind commercial ultraviolet glass in Chicago at street level.t Literature Cited(1) Blunt and Cowan, "Ultra-Violet Light and Vitamin D in Nutrition,"

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Section: Bloomingmentioning

confidence: 97%

“…Effect of Water on Shellac Shellac has been shown to be an ester condensation product (21), and it was first thought that the whitening of shellac films by soaking them in water might, in some manner, result from a partial hydrolysis of these ester linkages. When esters are hydrolyzed by water, constituent acids are formed.…”

Section: Bloomingmentioning

confidence: 99%

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2

Gardner¹

1931

Ind. Eng. Chem.

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“…Noteworthy, the key step in aforementioned synthesis involved acid-catalyzed formation of oxocarbenium ion. was further purified using silica gel column chromatography, to yield sesamolin (1 %w/w) as a white solid and its identities ( 1 H and 13 C NMR) were found to be identical with those reported in the literature [11]. This isolation methodology is summarized in…”

mentioning

confidence: 55%

Synthesis of new furofuran lignans through nucleophilic substitution of samin

Surachaitanawat

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The semi-synthesis of fifty furofuran lignans having a bicyclo[3.3.0]octane skeleton starting from the naturally available sesamolin is described. Our methodology involved protonation of samin to generate oxocarbenium ion followed by the attack of three different nucleophiles, namely, phenolics (ArOH), thiols (RSH) and alcohols (ROH). This synthesis strategy provided diastereomeric products except for those synthesized from samin and alcohols. The mechanism of stereoselective formation was investigated by 1H NMR monitoring technique and computational calculation. The results revealed that the products were presumably formed through SN1-like mechanism by protonation of the hemiacetal center of samin to generate the corresponding oxocarbenium ion as the intermediate. Subsequent reaction of this oxocarbenium ion with the alcohols then led to the observed exo,exo-alkoxysamin either directly, or alternatively, by protonation of the endo,exo-alkoxysamin through the SN2-like transition state.

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Studies on bleaching of lac I. Action of sodium hypochlorite on the resin

Khanna

1970

J. Appl. Chem.

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A study was made of physical and chemical changes that take place during bleaching of Rangeeni and Kusmi, the two main varieties of lac, by the improved hypochlorite bleaching process. The physical changes studied include life, flow and keeping quality. The chemical changes observed were oxidation, addition, substitution and partial hydrolysis. Fractionation and intrinsic viscosity, however, showed little overall molecular change.

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Nature and constitution of Shellac: IV. A study of the saponification number

Cited by 7 publications

References 4 publications

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2

Synthesis of new furofuran lignans through nucleophilic substitution of samin

Studies on bleaching of lac I. Action of sodium hypochlorite on the resin

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Nature and constitution of Shellac: IV. A study of the saponification number

Cited by 7 publications

References 4 publications

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films1,2

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films1,2

Synthesis of new furofuran lignans through nucleophilic substitution of samin

Studies on bleaching of lac I. Action of sodium hypochlorite on the resin

Contact Info

Product

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Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2

Nature and Constitution of Shellac III—Some Observations on Development of Opacity in Clear Varnish Films^1,2