DK164921B - PROCEDURE FOR REMOVAL OF PRIMARY AMINES FROM CONSIDERATIVE AROMATIC OILS - Google Patents

Description

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DK 164921 B

The present invention relates to a process for removing, in particular, primary amines from predominantly aromatic oils formed by hydrogenation or by pyrolysis of coal, oil shale, oil sands, mineral oil fractions and hydrocarbon-rich waste products.

It is known that during the hydrogenation or pyrolysis of these substances, primary amines are formed, some of which have toxic effects.

Analytical methods are known for separating 10 aromatic amines from such oils. For example

Analytica Chimica Acta, 134 (1982), 301-311 is thus known to isolate β-naphthylamine from oils by liquid chromatographic methods by which 50-80% of the amine present in ppm amount can be recovered.

Furthermore, gas chromatographic separation methods are known from Analytical Chemistry, Vol. 54 (1982), No. 1, 119, but these methods are unsuitable for technical use. Other physical separation methods are unsuitable due to the low concentration of amines 20 in the oils.

It is also known to remove amines from oils by leaching with sulfuric acid. However, at low amine concentrations, this process is not suitable.

The object of the invention is therefore to provide a simple, effective chemical process for removing primary amines from such oils. This is achieved according to the invention by treating the amine-containing oil with an oxidizing agent in the temperature range of 50 to 300 ° C for 0.5 to 48 hours.

Under these conditions, the amines are oxidized or dehydrogenated and a partial reaction occurs with other reactions.

DK 164921 B

2 tive components in the oil. The oxidation of pure primary and secondary amines is known, according to H.R. Christen, Grundlagen der Organchen Chemie, Verlag Sauerlander, 1970, p. 649. However, when the amines are diluted with a pure solvent, the strong dilution of the order of 10-1000 ppm shows that the oxidation proceeds only very slowly. Thus, when mesitylene having a content of 325 ppm 3-naphthylamine is aerated for 6 hours at 150 ° C with 10 liters of air per day. per hour per kg of oil, there is only a 10 decrease of the β-naphthylamine content to 309 ppm.

Surprisingly, it has been found that it is possible to oxidize primary amines and also in strong dilution when the amines are dissolved in oils from the hydrogenation or pyrolysis of coal, oil shale, oil sands, mineral oil fractions or hydrocarbon rich waste material such as e.g. . used tires. The amine oxidation rates in the different oils are different at the same temperature. One can conclude that the components of the oil participate in the oxidation in an unclear manner.

Oxygen-containing gases such as e.g. atmospheric air. The pressure has little influence. Under pressure, the solubility of the oxygen in the oils is increased, which increases the oxidation rate. Preferably, however, the oxidation of the amines is carried out under normal pressure because then no pressure apparatus is required.

For the oxidation, 1-30 liters / hour of air per kg of oil, preferably approx. 10 liters / hour.kg, which is dispersed in the oil.

For this purpose, mixing sirens, intensive stirrers, and bird bush dispersers, commonly used for aerating liquids, as well as venturi washers may be used. Simple aerators, such as sintering discs, sibonds, etc. are less suitable, since usually larger volumes of air are required to obtain sufficient admixture. The reaction temperature is preferably in the range of 100 to 35 200 ° C. Due to the content of aromatic hydrocarbons

DK 164921 B

3 in the exhaust air, it may be convenient to conduct the oxidation with oxidizing agents in liquid form, e.g. hydrogen peroxide, or in solid form, e.g. dibenzoylperoxide.

The appropriate oxidizing agent is selected, inter alia, taking into account 5 the further reprocessing of the oils.

The degradation of the primary amines is elucidated by β-naphthylamine. In the process of the invention, it is possible to reduce the amine content down to the detection limit of 1 ppm (high pressure liquid chromatography with electrochemical detection).

The process according to the invention is further elucidated by the following examples. The aeration tests are conducted in a 1 liter round-bottom flask with gas supply pipes, stirrer and reflux under normal pressure. 15 flasks of oil are placed in the flasks.

Examples 1-5 In Examples 1-5, β-naphthylamine is oxidized in various oils at 150 ° C under an air flow of 10 liters / hour / kg of oil. The following aromatic oils are used: 20 hydrocarbon oil A, boiling range 188 - 320 ° C, hydrocarbon oil B, boiling range 78 - 314 ° C, hydrocarbon oil C, boiling range 75 - 375 ° C, gas oil decomposition oil, boiling range 280 - 370 ° C, 25 coal tar oil, boiling range 300 - 450 ° C.

The results are given in Table 1 below.

DK 164921 B

4

Table 1

Ex-β-naphthylamine sem-Treatment Co c 1 ppm peeling time after 5 no. Oil __ (hours) __ oxidation oxidation 1 hydrocarbon oil A 21 368 112 2 hydrocarbon oil B 21 61 13 3 hydrocarbon oil C 21 53 35 4 pyrolysis oil 2 35 2 10 5 coal tar oil 24 20 4

Examples 6-8 Examples 6-8 illustrate the influence of the amount of air supplied on the degradation of a defined amount of β-naphthylamine in a synthesis oil. The same test setup and execution is used as in Examples 1-5.

The results obtained are listed in Table 2 below.

Table 2: β-Naphthylamine concentration (%), calculated on initial concentration

Example No.__ 6__7_ 8_ 20 Airflow 1 / kg.time__5__10__15_

Processing time (hours) 0 100 100 100 1 93.3 56.6 55.4 2 64.8 35.5 32.5 25 3 31.0 20.5 '3.8 4 15.5 9.1 1 5 6 , 1 1 -

DK 164921 B

5

Examples 9-12 Examples 9-12 illustrate the effect of solid oxidants at different temperatures and stirring times in the oxidation of β-naphthylamine. For all the oils 5 used, β-naphthylamine is added before the start of the experiment to clarify the oxidation effect. As the oxidizing agent, dibenzoyl peroxide is used. The tests are carried out in a 1 liter round flask with stirrer and reflux. The results are given in Table 3 below.

DK 164921 B

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Claims (5)

A process for removing primary amines from predominantly aromatic oils formed by hydrogenation or pyrolysis of coal, oil shale, tar sands, mineral oil fractions and hydrocarbon rich waste material, characterized in that the aromatic oil is treated with an oxidizing agent in the temperature range of 50 to 300 ° C for 0.5 - 48 hours. Process according to claim 1, characterized in that the aromatic oils contain primary amines in an amount of 10-1000 ppm. Process according to claims 1 and 2, characterized in that the oxidation is carried out under normal pressure. Process according to claims 1-3, characterized in that the oxidation is carried out at 1-30 liters / hour air per hour. kg of oil in a temperature range of 100-200 ° C. Process according to claims 1-3, characterized in that dibenzoyl peroxide is used as the oxidizing agent.