## 1 Introduction  
The processes of oxidation of organic compounds, consisting of an introduction of covalently bonded oxygen atom(s) into a molecule, are widespread both in nature (e.g., biochemical reactions, biomass combustion) and many fields of human activity (e.g., industrial chemical synthesis, combustion of fossil fuels). Of particular technological importance are the reactions of selective oxidation, which allow to obtain many products (including alcohols, aldehydes, ketones, carboxylic acids, and epoxides [1; 2; 3; 4; 5; 6]) important in various applications, such as production of plastics, synthetic fibers, cleaning agents, dyes, pharmaceuticals, flavors, or fragrances. Nowadays, the industrial process of oxidation of cyclohexane to cyclohexanol and finally to adipic acid (annual production of ca. 3 mln tonnes), is carried out using cobalt(II) or manganese(II) catalysts in the presence of nitric acid at 150-170 \({}^{\circ}\)C under pressure of 1-2 MPa O\({}_{2}\)[7]. The by-product of this reaction is N\({}_{2}\)O (recognized as a greenhouse gas), which is formed in amount of about 300 kg per 1 ton of the desired product. An advantage of this process is its relatively high selectivity (~83%), in view of low substrate conversion of 3-5%. In the Amoco process, terephthalatic acid is produced (ca. 24 million tons per year) by the oxidation of p-xylenein the presence of cobalt(II) and manganese(II) salts, bromine compounds, acetic acid at 175-225 \({}^{\circ}\)C under pressure of 1.5-3 MPa O\({}_{2}\)[8; 9]. This reaction proceeds with a fairly high conversion of 98% and selectivity of 97%. The presence of aggressive reagents, i.e., bromine compounds, results in the use of anti-corrosion materials (e.g., titanium-containing alloys) in installations, which significantly increases operating costs. Moreover, acetic acid oxidizes in parallel to CO\({}_{x}\), causing significant economic losses. Phenol is mainly obtained in an industrial scale by the Hock's process (approximately 12 million tons per year constituting about 95% of world production [10]) involving alkylation of benzene with propylene to cumene, which is then oxidized in the presence of air at 80-120 \({}^{\circ}\)C under pressure of 0.7 MPa O\({}_{2}\), forming cumene hydroperoxide [7; 11]. The last compound is subsequently decomposed with sulfuric acid to phenol and acetone. The end products of this three-step synthesis are obtained with only 30% yield. As shown above, the most important technological processes of oxidation of hydrocarbons and their derivatives have serious limitations related mainly to the formation of harmful by-products and low yields of expected products. Therefore, alternative solutions focused on, among others, development of more active and selective catalysts have been still developed. One of the more promising approaches is the use of \(N\)-hydroxyphthalimide (NHPI) as a catalyst. In the presence of this compound (10 mol%) with the addition of Mn(II) salt and acetic acid, the oxidation of cyclohexane to adip acid with the yield of 73% was carried out at 100 \({}^{\circ}\)C and 0.1 MPa O\({}_{2}\)[12; 13; 14]. Such a significant increase in conversion under milder conditions should be noted as a milestone in the development of oxidation technologies, which has been confirmed by launching pilot plant by Daicel Chemical Industry Ltd. [15; 16]. Similarly, NHPI was successfully used in the Amoco process, performed without the addition of bromine compounds [17]. In the presence of NHPI (20 mol%), cobalt(II) and manganese(II) salts, acetic acid, at 100 \({}^{\circ}\)C and 0.1 MPa O\({}_{2}\), terephthalalic acid was achieved at the yield of 99%. Furthermore, in the Hock process, the application of NHPI allowed the reaction conditions to moderate, increasing the yield from 30% to 80% (10 mol% NHPI, acetonitrile, 75 \({}^{\circ}\)C, ambient pressure) [18]. Moreover, NHPI was also used successfully in the oxidation of cellulose [19].