Abstract of
GB156329
p-Cymene is prepared from pine-needle oil fractions boiling at about 160 DEG C. by chlorination followed by steam-distillation of the product, in the manner described in the parent Specification. The yield of cymene is increased by heating the raw material with an inorganic or organic acid or acid salt, removing the reagent, fractionally distilling the product, and using the fraction boiling at 175 DEG C. for chlorination.
The herein described manufacture of para-cymene by subjecting the fraction of turpentine oil (pine-needle oil) that boils r-price 18.] -.
i 1 1 1 1 1 i56,329 about 1600 C. (in some cases after having heated it with an inorganic or an organic acid or acid salt, washed it with water, neutralised it, and then distilled it to collect the fraction boiling at 175 C.) to the action of chlorine, distilling the product with steam and finally after heating with a small proportion of an oxidising agent or a condensing agent, if necessary, rectifying the distillate.
Dated this 6th day of October, 1919.
ABEL & IMRAY, Agents for the Applicants, 30, Southampton Buildings, London, W.C. 2.
Hereford: Printed for His Majesty's Stationery Office, by The Hereford Times Ltd.
[Wt 70-125/7/1923.]
Description
[Second Edition I
PATENT SPECI FICATION Application Date: Oct. 6, 1919. No. 24,388/19.
(Patent of Addition to No. 142,738: Oct. 6, 1919.) Complete Accepted: Jan. 6, 1921.
COMPLETE SPECIFICATION.
156,329 Manufacture of Para-cymene.
We, BRITISH AND FOREIGN CHEMICAL PRODUCERS LiMiTED, of 10/12, Copthall Avenue, London, E.C. 2, do hereby declare the nature of this invention (as communicated to me from abroad by Rheinische Kampferfabrik G.m.b.H., of Diisseldorf-Oberkassel, Germany), and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:This invention relates to an improvement in or modification of that described in Specification No. 142,738, namely the manufacture of para-cymene from the fractions boiling at 1750 C. of Swedish, Polish and like turpentine oils (pineneedle oils) by treatment with chlorine, subsequent distillation with steam and rectification, in certain cases, after previous heating with small proportion of an oxidising agent or a condensing agent.
By the present invention the terpenes present in pine-needle oil which boil about 1600 C. may also be used for making para-cymene by the said manufacture.
This could not be foreseen because the terpenes boiling about 1600 C. are not chemically identical with the terpenes boiling at 1750 C. The chemical nature and constitution of the terpenes used cannot be stated, because they have not been hitherto sufficiently investigated.
It can only be said that they are different; both classes are only to be identified by their respective boiling points.
The yield of para-cymene is essentially increased if the treatment with chlorine is preceded by heating the fractions boiling at 1600 C. of the turpentine oils with an inorganic or an organic acid or acid salt, separating the reagent and purifying the hydrocarbons by fractional distillation.
The fraction boiling at 1750 C. is then used for further treatment with chlorine.
In this case the yield may be increased to about 75 per cent.
The treatment with chlorine and the isolation of the para-cymene from the product are the same as those described in the said specification.
The following examples illustrate the invention:EXAMPLE 1.
kilos of chlorine are gradually introduced at a temperature of about 10-80 C. into 20 kilos of pine-needle oil fraction of boiling point about 1600 C. The product is distilled with steam, the oil which passes over is heated with 0.5 per cent. of zinc chloride for about half-anhour under reflux and then distilled.
About 12 kilos of nearly pure para-cymene passes over.
EXAMPLE 2.
kilos of pine-needle oil fraction of boiling point 1600 C. are boiled in a reflux apparatus for about 3 hours with kilos of formic acid of 85 per cent.
strength. The mass is then washed with water, neutralised and purified by distillation. The fraction of boiling point about 1700 C. is then further treated as described in Example 1.
Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we
