The paper presents the results of studies on the reaction of liquid-phase aerobic oxidation of a mixture of C10-C20 hydrocarbons in the catalytic presence of nickel salts of natural petroleum acids (NPA) isolated from oil by leaching. The catalyst was preliminarily subjected to ultrasonic treatment for 1 minute in order to activate the particles. It is assumed that ultrasound contributes to the dispersion of particles and their uniform distribution in a mixture of hydrocarbons. It has been determined that the proposed scheme helps to accelerate the process of liquid-phase aerobic oxidation of hydrocarbons in a short time and increase the yield of target reaction products, namely synthetic fatty acids. It has been established that ultrasound used in autocatalysis of the oxidation of a mixture of hydrocarbons does not affect the process of accelerated conversion of hydrocarbons into oxygen-containing compounds and the acid number (A.n.), which is an indicator of the process of hydrocarbon oxidation, is equal to 7.5 mgKOH/g, with a reaction duration of 4 hours, and using a catalyst treated with ultrasound, this the number equates to 49.5 mgKOH/g for 5 hours. As a result of the research, it was noticed that the catalytic efficiency of micro-sized catalytic systems is increased through the use of irritating agents, that is, ultrasound. It is assumed that a synergistic effect is created between heterogeneous catalyst particles and ultrasound. Briefly, ultrasonication of catalyst particles causes them to disperse effectively, resulting in a wide active surface area of the catalyst.
Liquid-phase oxidation of paraffin hydrocarbons with molecular oxygen was carried out in a bubble-type oxidation unit in a glass reactor [1]. The nickel salt of natural petroleum acid (RCOO)2Ni, used in the oxidation reaction of hydrocarbons as a catalyst, was synthesized in laboratory conditions, according to the method given in [2]. Ultrasonic treatment of the catalyst in a mixture of hydrocarbons C10-C20 was carried out on a cavitation installation of the Hielscher brand ((Ultrasound Technology, made in Germany) UP200St. In the cavitation process, titanium santrode of the s26d7 brand (Hielscher) was used, with a diameter of 7 mm and an amplitude of 190 µm.
The research results on liquid-phase aerobic oxidation of paraffin hydrocarbons with molecular oxygen in the presence of nickel salt of PNA treated with ultrasound are shown below in Table down (Т = 135-1400С, amount of air – 100-120l/h) (SFA - synthetic fatty acids; SOFA - synthetic oxyfatty acids):
Hydrocarbons
|
Catalyst |
Amount of cat-st, % |
US, min |
Time of reaction., hour |
A.n. of reac.mix., mgКОН/g |
SFA |
SOFA |
||
yield % |
A.n. mgКОН/g |
yield % |
A.n. mgКОН/g |
||||||
C10-C20 |
- |
- |
- |
4 |
7.5 |
- |
- |
- |
- |
C10-C20 |
- |
- |
- |
12 |
39.1 |
4.02 |
- |
2.1 |
- |
C10-C20 |
- |
- |
2 |
4 |
10.32 |
- |
- |
- |
- |
C10-C20 |
(RCOO)2Ni |
0.1 |
1 |
5 |
49.5 |
11.3 |
183.1 |
3.3 |
201.7 |
As a result of the research, it was noticed that the catalytic efficiency of micro-sized catalytic systems is increased through the use of irritating agents, that is, ultrasound. It is assumed that a synergistic effect is created between heterogeneous catalyst particles and ultrasound. Briefly, ultrasonication of catalyst particles causes them to disperse effectively, resulting in a wide active surface area.
1. E Zeynalov, J Friedrich, A Aliyeva et.al. Plasma-chemically brominated single-walled carbon nanotubes as novel catalysts for oil hydrocarbons aerobic oxidation // Applied Catalysis A: General, Elsevier, 2013, 454, p. 115-118
2. A. Z. Aliyeva, H. C. Ibrahimov, E. G. Ismayilov, F. A. Amirov, N. M. Aliyeva. Effect of ultrasonic treatment of nanostructured Mn-containing catalyst for the oxidation of petroleum hydrocarbons // Theoretical and Experimental Chemistry, 2019, Vol. 55, No. 4, p. 287-292 (Russian Original 2019, Vol. 55, No. 4)