DE1518558B - Process for the partial hydrogenation of naphthalene - Google Patents

Description

1 2

From the German patent specification 1 094 740, one or the other activity-limiting measures are high

partial hydrogenation of polynuclear aromatic compounds, selectively effective and resistant to poison.

bonds to catalysts made from copper chromite It is an advantage of the new process that it and larger amounts of alkaline earth oxides exist, the throughput of larger amounts of material at high levels of known. According to US Pat. No. 2,475,718, 5 sentences are allowed and thus a higher space-time perspective the partial hydrogenation of naphthalene with yields than the known procedures. Raney alloys in aqueous-alkaline solutions Another advantage is the possibility of lower, or suspensions, but only very sensitive catalysts as well as unreine ones Starting materials can be used and the substances to be added and their conversion products Life of the catalytic converters is short. Furthermore, io gentler temperatures can be used; it from the USA patent specification 1 960 977 and this one achieves at the same time a much higher one French patent 667 241 known, Naph life of the catalysts as well as anyway thalin in the presence of compounds of molyb- an increase in the absolute yield, the more, for Danish and tungsten in a mixture with other parts are significantly more than 90% of theory. Catalysts at temperatures between 350 and 15 The catalysts used in the new process -800 ° C partially hydrogenate. The for these rectors consist of cobalt and nickel molybdate Actions required high temperatures occur and / or tungstate and, if desired, carrier Cyclohexane and decahydronaphthalene in substances such as silica, natural or artificial larger amount as by-products; also here silicates, clays or aluminum oxides, among which After a relatively short time, the catalysts lose, in particular, the shaped bodies containing silica of effectiveness. The same applies to those that are characterized by their particularly long durability, French patent 38 193 (addition to the molybdenum and tungsten can be mentioned French patent 667 241) used side represented in full, but not cobalt Catalysts. and nickel, both of which exist side by side.

Finally, in the German Auslegeschrift 25 it must be, although the molar ratios 1067 807 have been described, for the hydrogenation can vary within wide limits. In general, from aromatic hydrocarbons catalysts, one uses ratios of ¹ U to to use the nickel, molybdenum and optionally 1.5 mol of nickel, preferably from V ₃ to 1 mol, possibly tungsten compounds and one nickel per mole of cobalt Catalyst. These catalysts can be subjected to hydrogen sulphide treatment simply by mixing them, ie they are at least partially present as sulphides. Components or also by joint precipitation. In this case, nickel has already been wholly or partly replaced in a manner known per se from the halides, by cobalt, without a nitrate or oxalate being obtained. Is the use advantage would have shown. It is intended to cover the catalysis of carrier substances, so sulfurization - especially in these, optionally after a pretreatment connection with molybdates or tungstates - by heating to 500 to 1500 ⁰ C, with aqueous is per se as a means for Production of sulfur-resistant solutions or suspensions of compounds of hydrogenation catalysts is known. This treatment of the aforementioned metals, e. B. cobalt and nickel, however, apparently cause relatively high reaction temperatures, ammonium hydroxide, molybdenum or tungstic acid - over 300 ° C - and seem inevitable 40 or ammonium molybdate or ammonium wolf smoke against side effects, such as the deposition mat, and then soak them to higher temperatures , of carbon and. a loss of activity in the z. B. 400 to 600 ° C, heat; this results in the running of the operating time, making it susceptible, as one removes molybdates or tungstates of cobalt and the last-mentioned document (cf. column 12, lines 9 nickel. Then the catalysts up to 14) are removed. 45 then a follow-up treatment in reducing

The object of the invention is to create a catalyst medium, for example with hydrogen or hydrogen, with which the technically very important part-holding gases are subjected
wise hydrogenation of naphthalene to tetrahydro- The partial hydrogenation of naphthalene can also be carried out in a continuous process according to the new process at relatively low levels. Such a catalyst must be carried out at particular long-term temperatures; For this purpose, stability is chosen both with regard to the catalytic one in the range between 120 and 300 ⁰ C, in particular activity as well as with regard to the mechanical special between 180 and 280 ⁰ C. The pressure stability and must of course always be in the range from 40 to 300 atü, preferably to be able to be produced in a reproducible manner. 100 to 250 atmospheres are provided. The application of

It has now been found that tetrahydronaph solvents are not necessary, but have

thalin by partial hydrogenation of naphthalene with particular advantages if you use the naphthalene

Brings completely into solution with their help at elevated temperature and under elevated pressure. In question

a cobalt, nickel, molybdenum and possibly toluene, the xylenes, cumene,

Tungsten-containing catalyst in almost quantita- cyclohexane, tetrahydronaphthalene, decahydronaph-

tive yield and also in continuous thaline and other cyclic hydrocarbons,

drive with particular advantage if one of the embodiments of the new method

Naphthalene in the presence of a catalyst, which rens are in addition to the discontinuous above all

side by side cobalt and nickel molybdate and / the continuous mentioned as advantageous. Quite

or tungstate, and with hydrogen with particular advantages, those embodiments

has been post-treated at high temperatures, with 65 formation forms in which the components of the

a temperature between 120 and 300 ° C and are quickly mixed with each other when they settle, like that

hydrogenated at a hydrogen pressure of 40 to 300 atm. Trickle process in the liquid phase. You can do it

The new catalysts are V ₁₀ to V ₅ and more parts by volume an hour without sulphurisation

Claims (1)

3 4 Naphthalene solution per part by volume of catalyst converts carrier impregnated. After further treatment as in and at the same time, with almost complete conversion, Example 1 is the existing water and the am- The moniak evaporated for months without interruption or disturbance, and the cobalt as well as that Implementation work. Nickel is in the form of tungstates. Even the The parts mentioned in the examples are. Treatment of the catalyst with hydrogen is like weight parts; the parts of the room relate to them in Example 1 made. The same as liters to grams. That introduced in the examples is passed through the catalyst obtained in this way put crude naphthalene had a sulfur content of hourly the same solution as in Example 1 0.2 to 0.5 per cent, mostly between 0.2 and 0.3 per cent. a water pressure of 180 atü with a current .... ίο speed of 60 room parts per hour (on .Example 1 normal pressure calculated) and at a temperature 800 parts of molded silica are heated to 245 ° C. 4 to 8 hours in the temperature range from 800 to , 9 parts (= 92% of theory) of parts of freshly precipitated nickel hydroxide and 233.5 parts of tetrahydronaphthalene and 3.4 parts (= 8% of the ammonium molybdate in 10 weight percent theory) of decahydronaphthalene.
aqueous ammonia solution soaked until the entire. .
Solution has been absorbed by the carrier. Now example 3
heating the catalyst for 4 hours at 20 Man, clubs temperature operating as described in Example 1 of 25O ⁰ C, but existing turns 800 of water for preparing the catalyst and evaporate ammonia and the cobalt components to strands formed silica and one and the Nickel is converted into the molybdates solution of 42.2 parts of cobalt hydroxide, 42.3 parts of, and then treats it for 10 hours with nickel hydroxide, 233.5 parts of ammonium molybdate at a temperature of 280 to 310 ^° C. below 25 and 100 ° C Parts of ammonia in 1000 parts of water paint pressure with hydrogen gas. and one for hydrogenation. _v . Temperature of 245 ° C, A solution of 40 parts of sulfur-containing hydrogen velocity of 100 parts by volume of crude naphthalene in 120 parts of xylene is passed over the resulting catalyst at a pressure of 150 atmospheres per hour and one flow per hour (calculated at normal pressure).
Hydrogen pressure of 200 atmospheres with a flow rate of 30 From the reaction mixture, at a rate of separation of 70 parts by volume of hydrogen, the hydrogen and the solvent are separated for 39.5 hours (calculated at normal pressure), the one-part (= 96% of theory) of tetrahydronaphthalene transition temperature 3O ⁰ C, the temperature in the reactor and 1.7 parts is (= 4% of theory) of decahydro desk vessel 240 to 250 ⁰ C. The reaction naphthalene obtained
product is continuously discharged via a cooler,
pulled through a separator from hydrogen and claim:
then freed from the solvent by distillation. Process for the production of tetrahydro- From 40 parts of sulfur-containing crude naphthalene naphthalene by partial hydrogenation of Naphtha, 40.4 parts per hour (= 98% of the thalin at elevated temperature and below the theory) of tetrahydronaphthalene and 0.8 parts of high pressure in the presence of a cobalt, nickel, ( = 2% of theory) of decahydronaphthalene. Contains molybdenum and optionally tungsten- _R. . . the catalyst, characterized _{gekennzeichöebeispiel Z netj that} naphthalene in the presence of a 800 parts as in Example 1 pretreated shaped catalyst, the side by side cobalt and ter silica with a solution of 45.4 45 nickel molybdate and / or tungstate contains and Parts cobalt hydroxide, 14.8 parts freshly precipitated with hydrogen at elevated temperatures Nickel hydroxide, 215 parts of ammonium tungstate has been aftertreated at one temperature and about 100 parts of ammonia in 1000 parts of water between 120 and 300 ⁰ C and with a water Hydrogenated until the entire solution is absorbed by the pressure of 40 to 300 atmospheres.