DE767644C - Process for the production of aromatic hydrocarbons from mixtures of paraffins and cycloparaffins - Google Patents

Description

Process for the production of aromatic hydrocarbons from mixtures of paraffins and cycloparaffins The inventor: dun.g refers to a process for the production of aromatic hydrocarbons or mixtures containing them, like gasoline, from mixtures of paraffins and cycloparaffins that are more than 6 and have at most about 12 carbon atoms, by catalytic cyclization and or or dehydration. The cycloparaffins present in the starting material can have exclusively non-hydroaromatic character, such as cycloparaffins with 5 carbon atoms; However, they can also partially consist of cycloparaffins with hydroaromatic Character exist. It has been found that in the catalytic cyclization and dehydrogenation of some hydrocarbon mixtures increases the effectiveness of the catalyst drops rapidly as a result of the build-up of carbon-containing products.

This disadvantage is particularly pronounced when chromium oxide containing catalysts can be used.

It has now been found, surprisingly, that this disadvantage is mainly due to the presence of non-hydroaromatic cycloparaffins, in particular cyclopentane homologues (5-ring naphthenes) in the starting material. The process according to the invention is characterized in that the starting material is completely or partially freed from the aforementioned cycloparaffins of non-hydroaromatic character, in particular from cyclopentane homologues, before the catalytic cyclization and / or dehydrogenation. This liberation takes place by treating the starting material below 20o = with aluminum halides, in particular aluminum chloride. Double compounds of these substances with other metal compounds or complex compounds with organic substances, such as the so-called Gustavson compounds, together with hydrogen halide, such as hydrogen chloride. The aluminum halides can be used as such or on supports, such as kaolin. Silica gel and aluminum oxide, can be used: -One can for this purpose z. B. also use aluminum halides with viscous hydrocarbon oils, the z. F. are obtained by polymerizing propene with Al Cl. as a catalyst, to paste-like masses have been mixed.

The halides can also be formed during the treatment, z. B. by means of aluminum and chlorine, hydrogen. "-Eiterkin can also be complete" bindings formed by halides with organic substances under the Realztiansbedingtingen will. z. B. by having the treatment in the presence of aluminum chloride and tripropy 1-benzene executes.

When aluminum chloride is used. one preferably works in the liquid phase and at temperatures below iooc.

Particularly favorable results are obtained. when the procedure is carried out becomes in the presence of aluminum chloride. Hydrogen chloride and hydrogen, where the hydrogen pressure preferably exceeds about 10 atmospheres.

Under the conditions described above, the non-hydroaromatic earths Cycloparaffins, such as methylcyclopentane and other homologues of cyclopentane, in Cvciolietane and homologues thereof converted. Other hydrocarbons remain complete or almost completely unchanged.

The starting materials for the present process include the so-called distillate gasoline and gasoline, which by hydrogenation or by destructive hydrogenation full of mineral oils, coal, tar or. D-1. has been received. The treatment according to the invention increases the aromatic content of the gasoline. and the knock resistance is improved accordingly. so that the gasoline is converted into a more valuable product. EXAMPLE 1 A mixture of 10 percent by weight of ethylcyclopentane and 90 percent by weight of n-heptane was converted at a rate of v @@ n ']. = about 3.5 g, passed per hour at 465 "under atmospheric pressure over 6 cm3, = 5.3 g, of a catalyst which consisted of a mixture of 30 mol percent A1.03 and o llol percent Cr .., 03, the was pressed into grains with a diameter of about 1 mm and still contained 5% by weight of potassium in the form of KOH.

Measured over a period of 6 hours, an average of 18.2 percent by weight of aromatic hydrocarbons was formed. The activity curve of the catalyst fell after just 3 hours.

The same mixture of 2 # ethylcyclopentane and n-heptane was then made 10 hours at fiinertemperature in an autoclave with weight percent AIC13 and Treated 10 percent by weight of hydrogen chloride under a hydrogen pressure of 20 at. 2, # After the A1 C13 was poured off, the reaction product was washed with lye and water and then dried. The carbohydrate-free _iiscli was then used in the above treated in the manner described.

Flax over a period of 6 hours, an average of 30.1 percent by weight of aromatic hydrocarbons was found. and after 6 hours the effectiveness of the catalyst had not yet decreased. Examples One between 8; and HOC- boiling fraction of a hydrocarbon mixture which contained; -ring- \ aplitliene and originated from Romanian crude oil. was passed over a catalyst of the composition used according to Example i. After just 2 hours, a considerable reduction in the effectiveness of the catalyst was observed, namely a reduction to approximately half of the maximum effectiveness of the catalyst.

If, on the other hand, the hydrocarbon fraction was previously 10 hours at `o- in an autoclave with i percent by weight A1 C13 and o percent by weight H Cl under was treated with a hydrogen pressure from Soat. c-rgab: i an i .; facli higher maximum efficiency of the catalyst. while after # hours no decrease the effectiveness determined «could be grounded.

Example 3 A fraction of a Venezuelan distillate 1 1 petrol containing 5-ring laphthene and between. 85 and 10 ° boiling, was forced at a rate of -i 1 per hour and under a pressure of 15 atm together with 4 percent by weight of hydrogen chloride through a 2 liter stirred autoclave which contained 500 g of aluminum chloride. The autoclave was kept at 80 °.

The reaction product formed was used to remove aluminum chloride and hydrochloric acid washed with lye and water and then dried and distilled, the fraction boiling up to r25 ° was collected. In the gasoline mixture thus obtained -The 5-ring naphthenes which are detrimental to the catalyst are practically in 6-ring naphthenes converted.

This fraction was passed at a throughput of 0.38 kg per liter of catalyst and per hour over a catalyst which consisted of a mixture of 30 mol percent A12 03 and 70 mol percent Cr2 03, which was and still was pressed into grains about 5 mm in diameter 4 @ / s weight percent potassium in the form of KN 03 contained. Mixed with the gasoline fraction, hydrogen was passed over the catalyst at a rate of 2400 liters per kilogram of gasoline fraction.

The total pressure was 5 atm and the partial pressure of the hydrocarbons was 0.45 at. The reaction temperature during the first 6 hours was 525 ° during 54o ° for the following 6 hours and 56o ° during the last 6 hours.

The original gasoline fraction consisted of 6 percent by weight aromatics, 40 percent by weight paraffinic hydrocarbons and 54 percent by weight naphthenes.

A yield of 92% was calculated during the first 6 hours on the use, a liquid reaction product obtained, which consists of 79 percent by weight Aromatics, 5 percent by weight olefins and 16 percent by weight paraffins and contained little 5-ring napthene.

During the following 6 hours it was in a yield of 86 percent by weight Obtain a liquid product that consists of 83 percent by weight aromatics, 5 percent by weight Olefins and 12 weight percent paraffins and contained little 5-ring naphthenes.

During the last 6 hours, a yield of 79 percent by weight a liquid reaction product obtained, which consists of 8-2 percent by weight aromatics, 5 Weight percent olefins and 13 weight percent paraffins consisted and few 5-ring, taphthenes contained.

The catalyst was then revived by steaming for 3 hours 65o ° and regained its original effectiveness. Example 4-One between The fraction of borneo-gasoline boiling at 85 and 104 ° and consisted of 74 percent by weight Naphthenes., 3rd weight percent aromatics and 23 weight percent paraffins of the following. Subjected to treatment 750 g of the gasoline were treated with 40 g of aluminum chloride and 100 g of hydrogen chloride for 10 hours at 80 ° in a rotating V2 A steel autoclave of 2 liters capacity. This treatment resulted in 80 to 85% the originally existing 5-ring naphthenes are converted into 6-ring naphthenes.

The reaction product formed was used to remove the aluminum chloride and the hydrogen chloride washed with alkali and water and then dried. That The gasoline obtained consisted of 73 percent by weight of naphthenes and 2 percent by weight of aromatics and 25 weight percent paraffins.

That. The treated gasoline was mixed at a rate of 20 cm3 per hour with a 10-fold molar amount of hydrogen, about 240o liters per kilogram of gasoline, under a pressure of 6 atm over 36 cm3 of a catalyst composed of a mixture of 30 mol percent A1203 and 70 mol percent Cr203 obtained by precipitation of the mixed hydroxide, which was pressed into lozenges about 0.5 cm in size and also contained 16 mol of potassium in the form of potassium hydroxide for every 100 mol of oxide mixture.

The reaction temperature during the first 18 hours was 525 °, during the following hours 535 ° and during the last 6 hours 545 °.

When processing 498 g of treated gasoline, a total of 447 g of a liquid product obtained, which consists of 17 percent by weight \ taphthenes, 68 percent by weight aromatics, 10 percent by weight paraffins and 5 percent by weight aliphatic olefins.

The catalyst was then steamed at 65o ° for 5 hours regenerates under a pressure of 6 at, whereby it regains its original effectiveness received. Example 5 A fraction of a Venezuelan boiling point between 85 and 10 5 ° Gasoline, composed of 6% aromatics, 30% 6-ring naphthenes, 23% of 5-ring naphthenes and 41% paraffinic hydrocarbons, at a temperature of 60 ° with a Speed of 24 cm3 per hour together with 5 percent by weight of hydrogen chloride over So cm3, = 5.5 g, of a catalyst led, consisting of Activated charcoal with AI C13 applied in cash. This catalyst was made by Treatment of activated charcoal at 220 ° with A1 C13 steam. The liquid reaction product after an operating time of 5 hours contained 47% of 6-ring naphthenes, after 10 Hours I80/0, after 15 hours 50/0 and after 20 hours I; 7 0/0 6-ring naphthenes. The yield of reaction product boiling between 85 ° and 105 ° was 98 percent by weight.

The reaction product obtained was subjected to the cyclization by pouring it at a rate of 0.38 kg per hour over 1 liter of a catalyst consisting of a mixture of 30 mol percent A1.03 and 70 14 mol percent Cr pressed into cylindrical pills measuring 5 × 5 mm. 03, which also contained 12 atoms of potassium added as KOH to 100 atoms of Cr. In addition, 240o liters of hydrogen, measured at normal temperature and normal pressure, were passed over for every 1 kg of gasoline. The total pressure was 4 at.

During 6 hours at 525 ° 92% by weight of liquid product was collected with an aromatic content of 79% by weight. In the following 6-hour period at 5.10 °, 86 percent by weight of liquid product with an aromatic content of 83 percent by weight was collected and in a third 6-hour period at 560 ° C. 9 percent by weight of liquid product with an aromatic content of 82 percent by weight. The catalyst was then regenerated by steaming at 650 ° for 3 hours, which restored the original activity.

In the case of a cyclization of the original, i.e. not isomerized Gasoline under otherwise identical conditions became liquid at 525 ° by weight Product with an aromatic content of 75 percent by weight, at 5-0 ° 85 percent by weight Product with an aromatic content of 5o percent by weight and at 56o ° 8o percent by weight liquid product with an aromatic content of 28% by weight collected. the So the catalyst activity dropped much more quickly. The regeneration of the catalyst with steam at 65o it took 10 hours to work.

Claims (1)

PATENT CLAIM: Process for the production of aromatic hydrocarbons from mixtures of paraffins and cycloparafines with more than 6 and at most about 12 carbon atoms by catalytic cyclization and bz @ v. or dehydrogenation using catalysts containing chromium oxide, characterized in that the starting material, prior to carrying out the catalytic cyclization and / or dehydrogenation, of cyclopentane hydrocarbons by treatment with aluminum halides together with hydrogen halides. Treatment with aluminum halides together with hydrogen halides such as hydrogen chloride. and optionally hydrogen is freed, preferably under a pressure above about 10 atm. In order to differentiate the subject matter of the invention from the state of the art, the following publications were considered in the granting procedure: _N. D. Zelinskv and je. 11I. Schachnas aro "- a: Bull. Acad. Sci. URS S, Ser. chim., 1936, 5 5/71 to 576 reported in the Chemisches Zentralblatt 1938. I, 15o8; \ IB Turowa-Pol Jak and 0.j. Polyalkova: Chem. J. Ser.A. .. Journal for General Chemistry (Russian), Vol. 9, pp. 233 to 238; reported in Chemisches Zentralblatt 1939, 1I, 10-4.I; Per. D. German. Chem. Ges., 66, r933 1097 to 1100; Journ. Amer. Chem. Soc., 56 #. 1934, 1926 to 1928; C hem. Zentralblatt, 1931, Vol. I, pp. 3-19.