Methyl hydrogen adipate

By increasing the molar proportion of the monocarboxylic acid, the yield of (II) is improved. Thus electrolysis of a mixture of decanoic acid (n-decoic acid capric acid) (V) (2 mols) and methyl hydrogen adipate (VI) (1 mol) in anhydrous methanol in the presence of a little sodium methoxide gives, after hydrolysis of the esters formed, n-octadecane (VII), tetradecanoic or myristic acid (VIH) and sebacic acid (IX) ... 

Sebacic acid. Dissolve 40 g. of methyl hydrogen adipate in 100 ml. of absolute methanol to which 01 g. of sodium has been added. Pass a current of about 2 0 amps, until the pH of the solution is about 8 (ca. 5 hours) test with B.D.H. narrow-range indicator paper. Transfer the contents of the electrolysis cell to a 500 ml. round-bottomed flask, render neutral with a little acetic acid, and distil off the methanol on a water... 

Myristic acid from hexanoic acid and methyl hydrogen sebacate). Dissolve 23 -2 g. of redistilled hexanoic acid (re caproic acid), b.p. 204-6-205-5°/760 mm., and 21-6 g. of methyl hydrogen sebacate in 200 ml. of absolute methanol to which 0 13 g. of sodium has been added. Electrolyse at 2 0 amps., whilst maintaining the temperature between 30° and 40°, until the pH is about 8 0 (ca. 6 hours). Neutralise the contents of the electrolysis cell with a little acetic acid and distil off the methyl alcohol on a water bath. Dissolve the residue in 200 ml. of ether, wash with three 50 ml. portions of saturated sodium bicarbonate solution, once with water, dry with anhydrous magnesium sulphate, and distil with the aid of a fractionating column (see under Methyl hydrogen adipate). Collect the re-decane at 60°/10 mm. (3 0 g.), the methyl myristate at 158-160°/ 10 mm. (12 5g.) and dimethyl hexadecane-1 16-dicarboxylate at 215-230°/ 7 mm. (1 -5 g.)... 

To a solution of 33 g. (O.S mole) of potassium hydroxide (Note 1) in 1.5 1. of distilled water in a 5-1. flask or other appropriate container fitted with a mechanical stirrer is added 80 g. (0.5 mole) of methyl hydrogen adipate (Note 2). With continuous stirring a solution of 85 g. (0.5 mole) of silver nitrate in 1 1. of distilled water is added rapidly (about IS minutes). The precipitated methyl silver adipate is collected on a Buchner funnel, washed with methanol, and dried in an oven at 50-60°. For the next step the dried silver salt is finely powdered and sieved through a 40-mesh screen. The combined yield from two such runs is, 213 g. (80%). 

The methyl hydrogen adipate was Eastman Kodak grade. 

This method with some slight modihcations is applied in the synthesis of to-bromo esters from Cs to Cn. Methyl 5-bromovalerate has been prepared by treating the silver salt of methyl hydrogen adipate with bromine. The ethyl ester has been prepared from the acid by esterification or through the acid chloride. ... 

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

Simple anodic coupling by electrolysis in anhydrous methanolic solution (containing a little sodium methoxide) of methyl hydrogen adipate (Expt 5.147) gives dimethyl sebacate methyl hydrogen sebacate (Expt 5.147) in turn yields dimethyl octadecanedioate (Expt 5.131, cognate preparations). 

In Method B decanoic acid (2 mol) is coupled with methyl hydrogen adipate (1 mol) and the products are methyl myristate, octadecane and dimethyl sebacate. 

Method B. Dissolve 55.2 g (0.32 mol) of pure decanoic acid, m.p. 31-32°C, and 25.6 g (0.16 mol) of methyl hydrogen adipate in 200 ml of absolute methanol to which 0.25 g of sodium has been added. Electrolyse at 2.0 amps at 25-35 °C until the pH of the electrolyte is 8.2 (c. 9 hours). Neutralise the contents of the electrolytic cell with acetic acid, distil off the methanol on a water bath, dissolve the residue in about 200 ml of ether, wash with three 50 ml portions of saturated sodium hydrogen carbonate solution and remove the ether on a water bath. Treat the residue with a solution of 8.0 g of sodium hydroxide in 200 ml of 80 per cent methanol, reflux for 2 hours and distil off the methanol on a water bath. Add about 600 ml of water to the residue to dissolve the mixture of sodium salts extract the hydrocarbon with four 50 ml portions of ether, and dry the combined ethereal extracts with magnesium sulphate. After removal of the ether, 23.1 g of almost pure octadecane, m.p. 23-24 °C, remains. Acidify the aqueous solution with concentrated hydrochloric acid (c. 25 ml), cool to 0 °C, filter off the mixture of acids, wash well with cold water and dry in a vacuum desiccator. The yield of the mixture of sebacic and myr-istic acids, m.p. 52-67 °C, is 26 g. Separate the mixture by extraction with six 50 ml portions of almost boiling light petroleum, b.p. 40-60 °C. The residue (5.2 g), m.p. 132°C, is sebacic acid. Evaporation of the solvent gives 20 g (55%) of myristic acid, m.p. 52-53 °C the m.p. is raised slightly upon recrystallisation from methanol. 

The acid-catalysed reaction of a dicarboxylic acid with an excess of alcohol yields the diester. However, the process may be adapted to prepare acid esters of dicarboxylic acids by using molar proportions of the diacid and alcohol (e.g. methyl hydrogen adipate, Expt 5.147). Alternatively the acid ester may be prepared by subjecting the diester to controlled partial hydrolysis with one molar proportion of potassium hydroxide. 

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