DE133631C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

None of the known acetylenic acids Properties derived from esters have so far been observed which make these compounds technically useful could justify. While, the ethyl ester of propiolic acid a little violent, like horseradish odorous oil «, other esters of acetylenecarboxylic acids, such as. B. those of phenylpropiolic acid to be almost odorless. Some of these acids also appear to oppose difficulties to their esterification. This is how it is said of tetrolic acid: "The preparation of an ethyl ester does not succeed" (Lagermark, Beilstein 1893, I, 531). This is probably one of the reasons why so few esters of acetylenecarboxylic acids have been described have been.

It has now been found that the acetylenecarboxylic acids of the C ₈ and C _{9 series} (Patent 132802) can be esterified normally, and that the esters of these acids have properties which make them technically useful as fragrances in perfumery. The esters of acetylenecarboxylic acids can finally also serve as starting materials for the preparation of esters of β-ketonic acids with the same number of carbon atoms, which can also be used in perfumery.

The esters from the acetylenic acids mentioned are prepared by adding the Acids or their chlorides and any alcohol with or without the aid one of the common esterification agents (e.g. sulfuric acid) in the usual way allow each other to act.

However, these esters can also be obtained directly by reacting the metal compounds of the acetylene hydrocarbons C ₇ or C ₈ with the esters of chloroformic acid.

Example I.

Mix 1 kg of acid, 1 kg absolute Alcohol and 100 ecm sulfuric acid of 66 ° B., the mixture heated for 36 hours long in a water bath (with a larger amount of sulfuric acid, the heating time may be shorter be), lets the mixture cool down, dilutes it with an aqueous salt solution, to separate out the mineral acid, and then extract several times with ether or any other suitable solvent. The essential fluids will be combined, washed with an alkaline solution (from which the not in Ether recovered acid); it is then dried with calcium chloride and separated the solvent is removed by distillation in a water bath. The residue, which is the raw Forming esters is subjected to distillation in the air or by steam until a body of sufficient Maintains purity.

The representation of the chlorides. of the acetylenic acids described 'takes place in usual way, e.g. B. with the help of phosphorus chlorides.

1.4 kg of heptine carboxylic acid are slowly added dropwise to 2 kg of phosphorus pentachloride, which is well cooled and stirred by stirring, the mixture is warmed gently and then the product is boiled over in a vacuum. The chloride of the heptine carboxylic acid boils below 17 to. 18 mm print at around 87 to 91 ⁰ ,

the chloride of the octynecarboxylic acid under 23 to 24 mm pressure approximately at 112 to 116 °. Other known methods can also be used to prepare these chlorides, e.g. B. the Exposure to phosphorus trichloride, etc.

The esters from these chlorides are also prepared in accordance with those for the presentation common methods of esters. One drips z. B. in 1 1 absolute alcohol, which is well cooled, 2 kg of chloride, the mixture washes the mixture after a short period of time Dilution with ether with water, dries the ester, and purifies it by fractionation Distillation.

In order to obtain chlorine-free esters directly, the chloride is added dropwise in the same way Alcohol after having dissolved a little more than a molecule of sodium in it.

Example II.

100 parts each of heptine sodium, which in 1000 parts of anhydrous ether have been distributed, are gradually cooled, with good cooling 90 parts of ethyl chloroformate were added. After the reaction has stopped, run the mixture is left to stand for a few hours, stirring occasionally, and then washed then with water and clean the ester in the usual way.

The methyl ester of the acid C ₈ H _{v 2} O 2 distills at 103 to 1090 at a pressure of 20 to 21 mm; its specific weight at ^{0 ° is 0.932.}

The ethyl ester distills at 114 to 117 ° at a pressure of 17 to 18 mm; its specific gravity at ^{0 ° is 0.939.}

The isopropyl ester distills at 125 to 128 ⁰ at a pressure of 22 to 23 mm; its specific gravity at 0 ° is 0.918.

The isobutyl ester distills at 137 to 140 ⁰ at 23 to 24 mm pressure height, its specific gravity at 0 ° is 0.916.

The isoamyl ester distills at 147 to 150 ° at a pressure of 20 to 21 mm; its specific gravity at ^{0 ° is 0.911.}

The allyl ester distills at 123 to 129 ° at a pressure of 17 to 19 mm; its specific gravity at ^{0 ° is 0.946.}

The benzyl ester distills at 184 to 190 ° at a pressure of 16 to 18 mm; its specific gravity at ^{0 ° is 1.023.}

The ethyl ester of the acid C ₃ H _and O ₂ distills at 126 to 128 ⁰ at a pressure height of 16 mm, its specific gravity at 0 ° is 0.922.

The methyl ester of the acid C ₉ H _xi O ₂ distills at 122 ° at 19 mm pressure; its specific gravity at 0 ° is 0.933.

All these esters can be used in the fragrance industry because of their odor properties Find. Although the smells of these different compounds differ from each other and also more or less do not remind us of any flower or certain fruit, they do show Properties which are common to all of them and which are of particular value to them lend the perfumery.

By adding one or the other of these esters to mixtures of artificial fragrances the latter receive a finer, rounded and natural fragrance more similar smell.

These esters are however not only used as such, but they can also be used as starting materials for the production of ß-Ketonsäureester which have also aromatic properties and else as the esters of Acetylencarbonsäuren can be verwerthet in the industry in a similar W ^T.

In order to convert the esters of acetylenecarboxylic acids into / 3-ketonic acid esters, they can be used treat with sulfuric acid and then pour the reaction product into water.

Claims (1)

Patent claim: Process for the preparation of acetylene _{carboxylic acid esters of the series C 8} and C ₉ , consisting in letting the acetylene carboxylic acids or their chlorides which can be prepared according to patent 132802 act on alcohols, or the sodium compounds of hepine (ι) or octyne (1) with the esters of the Brings chloroformic acid to implement.