Resemblance

Anlhraquinone is a very stable compound which more closely resembles a diketone than a quinone it yields a monoxide with difficulty. 

CH3 CH0H CH20H, a colourless, almost odourless liquid. It has a sweet taste, but is more acrid than ethylene glycol b.p. 187. Manufactured by heating propylene chlorohydrin with a solution of NaHCO under pressure. It closely resembles dihydroxyethane in its properties, but is less toxic. Forms mono-and di-esters and ethers. Used as an anti-freeze and in the preparation of perfumes and flavouring extracts, as a solvent and in... 

Gattermann-Koch reaction Formylation of an aromatic hydrocarbon to yield the corresponding aldehyde by treatment with CO, HCl and AICI3 at atmospheric pressure CuCl is also required. The reaction resembles a Friedel-Crafts acylation since methanoyl chloride, HCOCl, is probably involved. 

Obtained as a syrup from plants of the Solanaceae family. Intensely poisonous, its action resembles that of atropine. Sedative in small doses. 

CH OfiSj, H2C(S03H)2- a colourless, crystalline solid which readily absorbs water vapour decomposes on distillation. The potassium salt is prepared by heating methylene chloride with an aqueous solution of potassium sulphite under pressure at 150-I60" C. The free acid is obtained by decomposing the sparingly soluble barium salt with sulphuric acid. The aryl esters are very stable, but the alkyl esters decompose on heating to give ethers. Resembles malonic acid in some of its reactions. 

Me2C = CHCOCH= CMca- Yellow liquid having a camphor-like odour m.p. 28 C, b.p. 198-5°C. It is formed when propanone is saturated with HCl and allowed to stand. Resembles camphor in many of its properties and is a solvent for cellulose nitrate. Used to prepare diisobutyl ketone (reduction). 

CHjlCH COOH. Colourless liquid having an odour resembling that of ethanoic acid m.p. 13 C, b.p. I4I°C. Prepared by oxidizing propenal with moist AgO or treating -hy-droxypropionitrile with sulphuric acid. Slowly converted to a resin at ordinary temperatures. Important glass-like resins are now manufactured from methyl acrylate, see acrylic resins. Propenoic acid itself can also be polymerized to important polymers - see acrylic acid polymers. 

CHjCOCOOH. A colourless liquid with an odour resembling that of ethanoic acid, m.p. 13 C, b.p. 65 C/lOmm. It is an intermediate in the breakdown of sugars to alcohol by yeast. Prepared by distilling tartaric acid with potassium hydrogen sulphate. Tends 10 polymerize to a solid (m.p. 92 C). Oxidized to oxalic acid or ethanoic acid. Reduced to ( + )-Iactic acid. 

It shows the usual carbohydrate reactions and most resembles mannose in behaviour it exists in OL and fi forms which exhibit mutarotation. 

Selenaies(VI) resemble sulphates but can be reduced more easily - to SeOs " -f-115 volts). Alums are formed. Pyroselenates, [OsSeOSeOs] " are known. 

C7H9N402- M.p. 337 C, an alkaloid obtained from cacao seeds or prepared synthetically. Constitutionally it is similar to caffeine, and is also a weak base. It is usually administered as the sodium compound combined with either sodium ethanoate or sodium salicylate, and is employed almost entirely as a diuretic. Physiologically theobromine resembles caffeine, but its effect on the central nervous system is less, while its action on the kidneys, is more pronounced. 

Auto-correlation and Inter-correlation Functions allow a good discrimination between these two types of defects by quantifying the resemblance between the different echoes and their derivatives. 

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