Esters, artificial

Use Propionates, some of which are used as mold inhibitors in bread and fungicides in general herbicides preservative for grains and wood chips emulsifying agents solutions for electroplating nickel perfume esters artificial fruit flavors pharmaceuticals cellulose propionate plastics. 

Uses as a mold inhibitor in bread and cheese products in fongicides and herbicides preservative for grains and wood chips in emulsifying agents in solutions for electroplating nickel, perfume esters, artificial fruit flavors, pharmaceuticals, and cellulose propionate plastics A... 

Some peptides have special tastes. L-Aspartyl phenylalanine methyl ester is very sweet and is used as an artificial sweetener (see Sweeteners). In contrast, some oligopeptides (such as L-ornithinyltaurine HQ. and L-oriuthinyl-jB-alariine HQ), and glycine methyl or ethyl ester HQ have been found to have a very salty taste (27). 

Aspartame is the market leader among artificial sweeteners. It is a methyl ester of a dipeptide, unrelated to any carbohydrate. It was discovered in the course of research directed toward developing drugs to relieve indigestion. 

Much of what is known about the chymotrypsin mechanism is based on studies of the hydrolysis of artificial substrates—simple organic esters, such as /Miitrophenylacetate, and methyl esters of amino acid analogs, such as... 

Delpbin has found an artificial ester as an a>Iulteraut of lavender oil which he believes to be the eibyl ester o[ the fatty acids of cocoa-nut oil. Ue has also definitely identified ethyl pbtbalale R an selul-... 

A terpene yielding isofenchyl alcohol on hydration, which Wallach considers to be one of the fenchenes, was artificially prepared by converting nopinone into a hydroxy ester by means of bromoacetic ester and zinc-dust. The hydroxy ester is dehydrated by potassium bisulphate, and so yields an unsaturated ester, which on saponification yields an acid from which the terpene results by distillation. This fenchene has the following characters —... 

Bodies of an alcholic nature play a very important part in both natural and synthetic perfumery. They are found to a very large extent in essential oils, both in the free state and also in the form of esters. Some that have not so far been recognised as constituents of essential oils, have been found to be so highly odorous, and so useful as perfume materials, that they are prepared artificially, and enter largely into the composition of the synthetic perfumes which to-day are indispensable to the manufacturer of perfumes. It is obvious that those alcohols which are soluble in water, such as methyl and ethyl alcohols, although they may be original constituents of some essential oils, are removed by the ordinary distillation processes, so that they do not, in fact, appear in the essential oil as found in commerce. 

Methyl Anthranilate.—This ester is one of extreme importance, and to it is largely due the possibility of manufacturing artificial neroli oils. It was discovered as a constituent of neroli oil in 1895 by Walbaum, and has since been identified in numerous other flower oils, such as tuberose, ylang-ylang, jasmin, and gardenia. Its value in synthetic perfumery is therefore obvious. Its constitution is that of a methyl ester or orthp-amido-benzoic acid, of the formula here shown —... 

Methyl Malonate.—This ester is an artificially prepared body, having a fruity odour, somewhat similar to the above-described esters of the fatty acids. It has the formula CH2(C02CHg)2, and boils at 181°. It may be prepared by treating potassium cyan-acetate with methyl alcohol and hydrochloric acid. On saponification with alcoholic potash it yields malonic acid, which melts at 132°, and serves well for the identification of the ester. 

Methyl Salicylate.—This ester is practically identical with oil of winter-green or oil of sweet birch, both of which contain about 99 per cent, of the ester. It is also present in numerous other plants, and its artificial production is carried out on a very large scale. The artificial ester is quite suitable for replacing the natural oil, and is used to a very large extent for flavouring tooth powders, pastes, and washes, being exceedingly popular in America. The ester has the constitution... 

Amyl Salicylate.—All the perfumes of the orchid type, and many of the Trifle variety, have amyl salicylate as one of their most important bases. The ester is known under the names orchid e, trefle or trefoil, and artificial orchid essence. It is used to a considerable extent in artificial perfumery. It is a colourless liquid of the formula... 

The esters belonging to the geraniol series of alcohols are absolutely indispensable in the manufacture of artificial perfumes. When it is remembered that these esters are present in such oils as bergamot, rose, geranium, lavender, petit-grain, neroli, and numerous other sweetsmelling essential oils, it will readily be seen how useful they are in building up similar perfumes artificially. 

This ester is indispensable in the reproduction of numerous flower oils in addition, of course, to artificial bergamot oil. 

Benzyl Acetate.—This ester is a constituent of the oils of jasmin, ylang-ylang, and similar flower oils. It has not a very intense odour, but is essential to the successful production of such perfumes as artificial jasmin. It has the formula CgHg, CH2. O. OCCH3. It is a colourless oU, boiling at 206° at ordinary pressure, and has a specific gravity 1-0570 at 16° and a refractive index 1-5034 . The propionic ester has the formula C0H5CH2OOCCH2CH3, and closely resembles the acetate in odour. 

Bornyl Acetate.—The acetic acid ester is the most important of the series. It is a constituent of pine-needle and rosemary oils, and has a most fragrant and refreshing odour. It is prepared artificially by the action of acetic anhydride on borneol, in the presence of sodium acetate, or by the condensation of borneol with glacial acetic acid in the presence of a small amount of a mineral acid. It is absolutely necessary in the reproduction of any pine odour. It is a crystalline body, crystallising from peDroleum ether in rhombic hemihedric crystals melting at 29°. The optical activity depends on that of the borneol from which it has been prepared. It has the following characters —... 

Terpinyl Formate.—The formic acid ester of terpineol, CjeHj-OOCH, occurs naturally in Ceylon cardamom oil. It is prepared artificially by... 

It is the acid constituent of the ester forming almost the whole of wintergreen and birchbark oils, and is a crystalline solid melting at 159. Commercially pure samples, however, rarely melt at above 157°. It is prepared artificially on an enormous scale by heating sodium phenol, under pressure, with carbon dioxide. 

Anthranilic acid, or o-amidobenzoic acid, C H (NH2)(COOH),. is the-acid constituent of the ester found in neroli, petit-grain, jasmin, and mandarin oils. It is a solid crystalline substance melting at 145°. It is prepared artificially, and then converted into synthetic methyl anthranilate.. To prepare anthranilic acid, o-nitrobenzaldehyde is reduced by tin and hydrochloric acid to anthranil,... 

The Detection of Artificial Esters in Essential Oils.—The custom of valuing certain essential oils, such as lavender, bergamot, geranium, petit-grain, etc., by the determination of their ester-content, has led to the use of scientific adulterants in the form of artificial esters which have been deliberately employed for the purpose of misleading the analyst. Of course, the ester determination is not a true criterion of value, as most of this class of oUs owe their perfume value to various other bodies as well. The first compounds of this nature employed for adulteration were ethyl succinate and ethyl oxalate. For the detection of these in lavender oil the foUowing test was proposed by Guildemeister and Hoffman —... 

The following methods for the determination of a number of artificial esters are reproduced, for the sake of completing the subject here, from Volume I of this work —... 

The author has recommended the examination of the last 10 per cent, left on evaporation of the oil on a water-bath, since the heavy artificial esters accumulate in this fraction. The refractive index of this 10 per cent, should not be below 1 5090, and the saponification value should not exceed 190. The following figures (see p. 317) represent nine samples of adulterated oil, all sold as genuine bergamot oil. 

Glyceryl acetate, which is an artificial ester commonly used in the adulteration of bergamot oil, is detected fairly easily on account of its high solubility in dilute alcohol. The test is carried out as follows Ten c.c. of bergamot oil and 20 c.c. of 5 per cent, alcohol are well shaken in separating funnel, and after the solutions have separated and become clear the watery solution is run off and filtered. Ten c.c. of the filtrate are exactly neutralised with deci-normal alkali, and then 5 c.c. of seminormal alkali run in, and the whole saponified under a reflux condenser for one hour. In the case of pure bergamot oil 0 1 or at most 0 2 c.c. of semi-normal alkali will have been used up by the saponification, whilst each 1 per cent, of glyceryl triacetate present in the oil will be represented by practically 0 5 c.c. of semi-normal alkali. 

Esters are important substances. The esters of the low molecular weight acids and alcohols have fragrant, fruit-like odors and are used in perfumes and artificial flavorings. Esters are useful solvents this is the reason they are commonly found in model airplane dope and fingernail polish remover. 

In condensation polymers, the monomers are linked together by condensation reactions, like those used to form ester or amide links. Polymers formed by linking together monomers that have carboxylic acid groups with those that have alcohol groups are called polyesters. Polymers of this type are widely used to make artificial fibers. A typical polyester is Dacron, or Terylene, a polymer produced from the... 

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