DE234912C - - Google Patents

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PATENT OFFICE.

PATENT LETTERING

- JVr 234912 -: CLASS 12 or GROUP

Patented in the German Empire on March 20, 1910.

Although all theoretically possible dichloronaphthalines are known, have the same has not yet found any technical application. This fact is on the one hand because of this explainable that most of these dichloronaphthalines are uniform only on technical not possible detours, z. B. from the corresponding aminonaphthalene sulfonic acids, Aminonaphthols, chloronitronaphthalenes

ίο etc. have been received (see Armstrong and Wynne, Reports 24, Refs. 655-659; Atterberg, Reports 9, 1187-1189, 1732; Claus and Zimmermann, Reports 14, 1477; Cleve, Reports 19, 2181; 20, 1991; 21,896; 23-954; 24, 3475; 25, 2489; Annual reports 1876, 675; Erdmann, Annalen 247, 351, 353, 362, 378; 275, 257; Reports 21, 3444; S. Forsling, Reports 20, 2102; Friedlaender and Szymansky, reports 25, 2081). on the other hand have since been able to remove the resulting from the action of chlorine on naphthalene Addition products only mixtures of the various homonuclear dichloronaphthalines (1 · 2, ι · 3, ι · 4 and 2 · 3) are obtained, and individual isomers could be isolated from these mixtures in a complicated, technically inconceivable way (see Armstrong and Wynne, Proc. Chem. Soc. 1888, 106; 1890, 85; Faust and Saame, Annals 160, 65 to 73; Krafft and Becker, Reports 9, 1088 to 1090; Leeds and Everhart, At the. Soc. 1880, II, 211; O. Widman, Reports 15, 2160-2163). Also the further chlorination of α-chloronaphthalene did not lead to any better results, as in this one too Trap next to small amounts of 1 ■ 4-dichloronaphthalene mainly by addition products arise (see annual reports of Ch. 1877, 406; 1879, 390; reports 10, 1724; 12, 1714; Bull. Soc. chim. Paris, 28 [1877], 5 ° 7) ·

It has now been found that completely different results are obtained when using naphthalene in the presence of a chlorine carrier, expediently with the aid of a solvent or diluent and use of a lower temperature with that required for the formation of dichloro substitution products Amount of chlorine treated. In this way of working, which has so far been the case in the naphthalene series only for the production of i-chloronaphthalene has been used (cf. failed application O. 1921, IV / 22 of June 3, 1893 by the company K. Oehler in Offenbach a. M .; Friedlaender, "Advances in Tar Colors - Fabrication", Volume III, p. 438), surprisingly arise in a vast majority (easy 80 percent and more) only two isomers, namely the ι · 4- and 1 · 5-dichloronaphthalene, while only a few percent of ι · 2- and 1 · 7-dichloronaphthalene were found as by-products that could be. About these by-products and any remaining ones remove small amounts of i-chloronaphthalene, the chlorination mixture can first be freed from the chlorine carriers used and either subjected to fractional distillation, expediently in vacuo, or from suitable Solvents such as B. Hplzgeist, be recrystallized, or it will be the both methods applied.

A far simpler and better way of working up, however, results from the over-

The behavior of the isomeric dichloronaphthalenes towards the mild ones is quick and completely different Sulfonating agents. While namely the ι · 2- and ι · 7-dichloronaphthalene and also that i-chloroprnaphthalene still present in the chlorination mixture are very easily sulfated, ι · 4- and 1 · 5 - dichloronaphthalene remain under unchanged under the same circumstances and can therefore be easily isolated in a mixture. This mixture is extremely suitable for many technical purposes.

Example 1.

In a mixture of 3840 parts of naphthalene,; ' 30 parts of sublimed ferric chloride and 6000 parts of carbon tetrachloride become slowly at -10 to 0 ° with thorough stirring Initiated 4250 parts of chlorine. It is then filtered off from the iron chloride and the reaction product after the carbon tetrachloride has been distilled off distilled in vacuo.

Instead of iron chloride, antimony pentachloride, phosphorus pentachloride, iodine, sulfur, etc. can also be used as chlorine carriers. After removing the chlorine carrier, the product is preferably subjected to vacuum fractional distillation and collected at about 40 mm, the pressure of about 170 to 190 ⁰ passing over the main product. It is then recrystallized once or twice from boiling wood spirit, the mixture of 1x4 and 1x5-dichloronaphthalene being obtained as a pure white, crystalline powder which melts at about 50 to 60 °, while the isomeric dichloronaphthalenes remain in the mother liquor.

Example 2..

100 parts of that obtained in Example 1 Chlorination product in 600 parts of sulfuric acid of 66 ° Be. registered and the mixture was then stirred at ordinary temperature for about 20 hours. After this Time is allowed to run in the reaction mass in about parts of water and sucked the precipitated mixture of 1x4 and 1x5 dichloronaphthalene away. It goes without saying that the amount and concentration of sulfuric acid can vary depending on what is present during the sulphonation Temperature can be varied.

Claims (2)

Patent Claims: 1. Process for the preparation of a mixture of ι · 4- and 1 · 5-dichloronaphta-Hn, consisting in the fact that naphthalene in the presence of a chlorine carrier, expedient at low temperature, possibly using a solvent or diluent treated with the amount of chlorine required for the formation of dichloro substitution products and from the resulting The reaction product is the isomers and byproducts formed in the process removed due to the different solubility or volatility. 2. Special embodiment, consisting in the fact that to remove the By-products treated the mixture of the isomeric dichloronaphthalene with sulfuric acid of such a concentration that 1 · 4- and r · 5 - dichloronaphthalene remain unaffected, while the isomeric dichloronaphthalene etc. are converted into sulfonic acids.