Research of a New Pigment Based on Copper Phthalocyanin in Paint Coating Materials

Home , Isoindole, Phthalimide, Phthalocyanine

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

Yusupov M.O.1, Beknazarov Kh.S.2, Tillaev A.3, Dzhalilov A.T.4

1Doctoral student of Namangan Engineering and Technology Institute, Namangan city 2Dr. Tech. sciences, leading researcher of Tashkent research institute of chemical technology, Republic of Uzbekistan, Tashkent region, Tashkent district, Shuro- bazar post office 3PhD in Technical Sciences, Senior Researcher of Tashkent research institute of chemical technology, Uzbekistan, Tashkent 4Dr. Chem. sciences, academician of the Academy of Sciences of the Republic of Uzbekistan, Tashkent Research Institute of Chemical Technology, Uzbekistan, Tashkent

Abstract The article analyzes the various properties of the synthesized copper, nitrogen and phosphorus-containing phthalocyanine pigments by IR spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and elemental analysis. The analysis shows that the synthesized new phthalocyanine pigment contains 8.3% copper in elemental analysis, and other properties of the pigment in the paint material were also determined.

1. Introduction Paints have been widely used in various fields since ancient times. Currently, the volume of work in the construction industry in the world and in the country is growing rapidly, which, in turn, has led to a rapid increase in demand for paints and varnishes. In the paint industry, pigments play an important role. Despite the fact that phthalocyanine pigments have been discovered over the past 100 years, the attractiveness and brightness of such pigments as objects of study has been the subject of different colors and people's interest. Today, world scientists pay great attention to the constant use of phthalocyanine pigments in various fields of science and technology [1]. Such pigments can be used as light stabilizers of polymeric materials [2]. Phthalocyanines (Pc) are a class of photoactive compounds whose unique physicochemical properties are studied in many areas of modern science. Pc metal complexes - phthalocyaninates (MPc) - are the products of large-tonnage industrial synthesis (over 80 thousand tons per year), with most of them traditionally used as pigments in the composition of color printing inks, paints and varnishes, for coloring plastics and synthetic fibers [3 ]. However, the structure of the molecules and the features of the formation of phthalocyanine crystals are responsible for their extremely low solubility in most media

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and high hydrophobicity. This is manifested in the difficulty of dispersing MPc in polar systems (due to the lack of wetting) and flocculation of their particles in non-polar [3], significantly limiting the use of these pigments in traditional and new areas. Phthalocyanines (Pc) - tetraazobenzoporphyrins, higher heterocyclic compounds, consist of isoindole (benz [c] pyrrole) rings, interconnected via sp2-hybridized nitrogen atoms, structurally related to natural porphyrins (Fig. 1a, b). However, unlike porphyrins, phthalocyanines are not found in nature, they are completely synthetic compounds. The main difference between the phthalocyanine macrocycle and the porphyrin system is the presence of four phenylene rings and nitrogen atoms in the meso positions instead of carbon.

a b c

Figure 1. Molecular structure of (a) porphyrin, (b) phthalocyanine, and (c) tetrapyrazinoporphyrazine macrocycles.

Porphyrazines are phthalocyanine analogs in which phenylene groups are substituted by various alkyl, aryl substituents and macrocycles. When replacing the phenylene fragment with pyrazine, tetrapyrazinoporphyrazines can be obtained (Fig. 1c), which already contains sixteen nitrogen atoms. The vast majority of phthalocyanines produced (~ 90%) are used as pigments and dyes [4]. Since the discovery and identification in the early 1900s [5] phthalocyanines have been widely used as dyes and pigments in the paint, varnish, printing, textile and paper industries because of their rich and bright blue-green color, photo stability, insolubility in most solvents and chemical inertness. Despite the very large number of Pc derivatives obtained in recent decades, several representatives of this class of compounds that were discovered back in the 30s of

the last century continue to have the highest industrial value: metal-free H2Pc, copper complex CuPc, and chlorinated derivatives CuPc-Cln (n = 1- 15) [3]. The approaches to their preparation are well studied and debugged in industry, which ensures their low cost (7-15 € for CuPc) [3]. In general, the synthesis of the basic structure of Pc requires the presence of phthalogen for the construction of isoindole fragments and a nitrogen source for the formation of azomethine bridges between them. Cyclic tetramerization of phthalogens is accelerated in the presence of metal ions that perform a coordinating function [6]. Most global manufacturers obtain CuPc by heating to 200 ° C a mixture of phthalic anhydride, urea, copper chloride and a catalyst (usually ammonium molybdate or

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

molybdenum oxide) in a high boiling point (> 180 °C) solvent (most often in kerosene, trichlorobenzene or nitrobenzene) . The highly exothermic reaction of the formation of an aromatic macrocycle proceeds from 2 to 8 hours with a yield of up to 90%. This process can also be carried out without the use of a solvent: ―dry sintering‖ of the same components at an elevated temperature of 200-300 °C. In this case, the reaction proceeds faster, more environmentally friendly and technologically simpler, as the resulting product requires additional purification. To obtain higher purity phthalocyanines, phthalonitrile is used as phthalogen, which also contains a sufficient number of nitrogen atoms for the formation of a macrocycle. As with phthalic anhydride, the process can be carried out in a solvent medium or by fusion using the same catalysts. A distinctive feature of this method is the formation, along with the main product, of partially chlorinated CuPc (when using copper chlorides as a source of metal ions), which, nevertheless, can be useful for obtaining a pigment resistant α phase form. Chlorination is suppressed in the presence of ammonium or urea salts. Industrial production of phthalocyanine pigments from phthalonitrile is greatly limited by its inaccessibility [3]. Green polyhalogenated pigments can be obtained in a similar way to CuPc synthesis — based on halogenated phthalic anhydride or phthalonitrile [7], but, due to the high cost of substituted phthalogens, the main industrial route for their synthesis is gas phase chlorination (bromination) of CuPc in a eutectic mixture of NaCl / AlCl3 at 200 ° С in the presence of a catalyst (e.g., FeCl3). The hue of such pigments depends on the ratio of Cl and Br atoms in the molecule, as well as the total number of halogen atoms (it is not economically feasible to introduce more than 14-15 substituents, as well as to obtain exclusively brominated or fluorinated derivatives) [3].

2. Experimental Methodology Synthesis of Copper Phthalocyanine by Urea Adduct The synthesis processes were carried out in two ways: in a solvent medium and at a high heating temperature. Synthesis in a solvent environment. 92 g (0.5 mol) of the urea adduct is added to a 1500 ml flask equipped with a mixer, thermometer and refrigerator, 60 g (1 mol) of urea, 294 g (2 mol) of phthalimide, 80 g (0.5 mol) of sulfate copper (II), ammonium heptamolybdate 1% by weight of phthalimide and 800 ml of dimethyl sulfoxide (DMSO) as a solvent. The boiling point of DMSO in the reaction mixture is 189 ° C., and the reaction mixture is stirred at this temperature for 3 hours. After completion of the reaction, the room is cooled to room temperature. Dilute with distilled water and precipitate the resulting product. The product is filtered, washed and dried in an oven at 50 ° C until its weight becomes constant. The yield is 95%. Synthesis at high heating temperature. 16 g (0.16 mol) of phosphoric acid, 24 g (0.4 mol) of urea were placed in a 500 ml acid-resistant living metal autoclave, stirred until dissolved at 130 °C, then 8 g (0.05 mol) of copper (II) sulfate was added, 12 g (0.2 mol) of urea, 29.4 g (0.2 mol) of phthalimide, and ammonium heptamolybate was added as a catalyst in 1% by weight of phthalimide until it became homogeneous (light blue). The resulting mixture was heated to 280 °C in an oven for 3 hours. The reaction mixture is then cooled to 50 °C and dissolved in 85% sulfuric acid. Then boiling water was added to the molten product and mixed. In this case, the starting non-reaction products and

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intermediates are dissolved in hot water. The resulting phthalocyanine is precipitated from solution. The precipitated phthalocyanine pigment is filtered through a Buchner funnel and washed several times with distilled water. The product was dried in an oven at a temperature of 50 ° C. The yield is 85%. Infrared spectroscopy (IR). The IR spectra of the synthesized compounds were recorded on IRTracer-100 spectrophotometers. Samples were taken in the form of solutions of viscous-liquid oligomers in certain solvents. The kit of the IRTracer-100 Infrared Fourier Spectrometer (SHIMADZU CORP., Japan, 2017) consists of a prefabricated impaired total internal reflection (ATR) MIRacle-10 and a diamond / ZnSe prism (the spectral range on the wave number scale is 4000 ÷ 450 cm - 1. Parameters of the IRTracer-100 Fourier spectrometer: resolution - 4 cm-1, sensitivity signal-to-noise ratio - 60,000: 1; scanning speed - 20 spectra per second). Thermal results were obtained using differential scanning colorimetry on a LABSYS EVO STA device (France). Differential scanning calorimetry (DSC) is a method used to study the reaction of substances when heated. DSC installation consists of a measuring chamber and a computer. Two cups are heated in the measuring chamber. The first cup contains the test material, and the second, as a rule, is empty and is used as a reference. The computer is used to control the temperature and adjusts the speed at which the temperature of the cups changes. A typical heating rate is about 10 °C/min. All measurements were carried out in an inert nitrogen atmosphere with a nitrogen flow rate of 50 ml/min. The temperature range of measurements was 25-370 °C, the heating rate was 5K/min. The amount of sample per measurement is 5-10 mg. The measuring system was calibrated with a

standard set of substances KNO3, In, Bi, Sn, Zn. Scanning electron microscopy (SEM). The morphology of the hydrated phases and the change in the structure of the composition depending on the oxidation conditions and the type of additives were studied using a scanning electron microscope from Jeol Interactive Corporation, Japan JSM-6460LA with the following technical characteristics: Resolution: 4.0 nm (at 30 kV); Accelerating voltage: from 0.1 to 4.9 kV (in 10 V increments), from 5 to 30 kV in increments (100 V); Magnification: from x8 to x 300,000; Samples for testing in an electron microscope were metallized at a vacuum station by sputtering a platinum layer 10–20 nm thick. To decode the images, we used literature and microprobe data on an Oxford X- ray microanalyzer, which allows determining the elemental composition of the phases of the composition with an accuracy of 0.5%.

3. Results and its discussion Study of the synthesis of copper phthalocyanine based on urea adduct The synthesis of a new composition of the copper phthalocyanine pigment (AddCuPc) based on the urea adduct was obtained in two different ways, studying its intensity, the effect of the color change of acrylic-based varnish materials, and some physical properties. The second method for producing pigments, based on research results, is the synthesis in dry mass, although less effective than in the first method, but

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

only because of its intensity, elasticity and active effect on the pigment obtained in a solvent medium. The synthesis of the obtained substance is as follows:

O O O

CuSO H2N C O P O C NH2 + 2 NH2CONH2 + 4 +

NH CH CH 2 O N C N Cu N C C O O C O kt, 280oC + 4 NH P N N O C CH CH C H H2N O O N N N C C

Based on the above formula, the efficiency of the synthesis processes was studied as a function of temperature, which is shown in Fig. 1.

100

60 200 250 40

The output The 280 20

0 0 50 100 150 200 Time, min

Fig. 2. The effect of temperature on the synthesis of the product of the copper phthalocyanine pigment (AddCuPc) by heating based on the urea adduct.

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

Temperature plays an important role in the high intensity of the pigment, and at the same time, when the temperature exceeds the standard, the product yield is significantly reduced. The synthesis of pigments was carried out at temperatures of 200, 250 and 280 ° C. For the synthesis of intense pigment, as shown in Figure 2, an optimum temperature of 280 ° C was chosen. Thus, the product yield after two hours was 89%, and after three hours the yield decreased to 85%. The pigment intensity at a yield of 85% is much higher.

Fig. 3. IR spectrum of AddCuPc pigment

The IR spectra of AddCuPc pigment [8] show the presence on the absorption curves of C = N stretching vibrations containing an aromatic ring at 1462.04-1608.63 cm-1. The absorption of the pyrrole ring is observed in the region of 1504.48 cm-1, the absorption of the bands in the region of 1163.08 cm-1 determines the interconnected molecules P - O bonds, P - N bonds appear in the region of 1286.52 cm-1. In the absorption regions of 457.13–638.44 cm-1, complex compounds of metallic Cu with nitrogen and oxygen are observed. Uneven deformational vibrations of C - N in the region of 1000–650 cm-1. The absorption range of 2000–1600 cm-1 has a weak band (composite frequencies), which is determined by the amount and position of all aromatic compounds by the type of replacement of the benzene ring. As shown in the literature [8], phthalocyanine-based pigments are heat-resistant; therefore, we studied the heat resistance of synthesized pigments. In fig. 4 shows that the thermal analysis of 35 mg of AddCuPc pigment, which was measured to a temperature of 500 oC, at this temperature, the mass of the substance decreased by only 26.5 mg, or 24.2%.

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

Fig. 4. Thermal analysis of AddCuPc pigment.

Thermal analysis of AddCuPc pigment was carried out in the temperature range 100-500 ° C, and the amount of energy consumed in the process increases. Compared to other pigments, phthalocyanine-based pigments are more resistant to high temperatures, as shown in table 1.

Table 1: Temperature values of AddCuPc pigment Amount of energy The remainder of The remainder № Temperature,оС consumed the mass, mg of the mass,% (µV*s/mg) 1 100 34.4 1.71 2.6 2 200 33.1 5.41 3,38 3 300 31.0 11.4 5,89 4 400 28.2 19.4 4,02 5 500 26.5 24.2 6,18

The synthesized new compound AddCuPc pigment was studied by scanning electron microscope on a serial EVO device (Zeiss, Germany). Using this method, we studied images and elemental analysis of pigment.

а) b) Fig. 5. Improved image of the new copper-containing pigment AddCuPc in an electron scanning microscope (SEM). a) the image of copper phthalocyanine in the form of pores 200 times and (b) 500 times larger

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

In the next step, AddCuPc pigment was pressed into a tablet using a special clamping device for determining elemental analysis of the pigment using a Zeiss OXFORD instrument.

Fig. 6. Elemental analysis of copper-containing pigment AddCuPc.

Using the elemental analysis shown in Figure 6, the number of elements in AddCuPc is shown in Table 2 below.

Table 2: The composition of the elemental analysis of the pigment AddCuPc Element C N O P Cu Mo Weight.% 59.56 13.06 10.39 4.49 8.34 4.16 Sigma Weight.% 0.90 1.04 0.39 0.17 0.32 0.37

Based on this analysis, the structure of the above pigment formula AddCuPc is compiled. The synthesized new compound AddCuPc, used to obtain acrylic-based coatings. Pigment based on AddCuPc was added to acrylic-based paints and varnishes in various amounts, and the optimum value for the pigment was 4.5% at 100% content of paints and varnishes, the data are shown in table 3.

Table 3: Formulation of acrylic paint and varnish material Paint Paint Titan AddCuPc bentonite mix MEK Nefras Mel Content % 69,8 0,5 4,5 0,4 0,2 0,3 4,26 20,04

After the preparation of an acrylic paint material based on AddCuPc, the thermal properties were studied to a temperature of 500 ° C, the initial mass was 45 mg, the mass was reduced to 38.3 mg with a loss of 14.8%.

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

Fig. 7. Thermoanalytical analysis of acrylic-based varnish with 4.5% AddCuPc pigment.

Thermoanalytical analysis of acrylic-based varnish with 4.5% AddCuPc pigment was carried out at a temperature range of 100-500 ° C, which increased the energy consumption in the process, while an additive based on phthalocyanine increased the varnish resistance to high temperatures. The effect of high temperature on the mass of varnish is shown in table 4.

Table 4: Temperature performance of paint based AddCuPc pigment Количество Остаток Остаток № Температура,оС потребляемой массы, мг(45) массы, % энергии (µV*s/mg) 1 100 44.8 0.44 3.6 2 200 42.8 4.88 4,33 3 300 40.0 11.1 3,82 4 400 38.5 14.4 3,62 5 500 38.3 14.8 4,18

In Fig. 8. Elemental analysis and micrographs of an acrylic lacquer coating based on a 4.5% pigment AddCuPc composite are given.

а) b) Fig. 8. Micrographs of the acrylic lacquer composition of 4.5% AddCuPc pigment on an electron scanning microscope (SEM). a) 250-fold and (b) 500-fold image of varnish based on AddCuPc pigment coated on metal.

International Journal of Advanced Science and Technology Vol. 29, No.03, (2020), pp.2244-2254

A paint based on AddCuPc pigment was applied to a metal surface and placed in a special conductive metal device, and an elemental analysis of the paint composition was determined by Zeiss OXFORD devices.

Fig. 9. Elemental analysis of the composition of the acrylic-based varnish with the addition of 4.5% AddCuPc pigment.

Elemental analysis of acrylic paint based on the addition of 4.5% AddCuPc pigment shows the composition of acrylic paint, as can be seen from Fig. 9, phosphorus is not visible due to the low content in the paint, the data are shown in table 5.

Table 5: Elemental composition of acrylic-based varnish with pigment AddCuPc Element C N O Mg S Ca Cu

Weight.% 44.87 39.20 13.30 0.29 0.13 1.83 0.38

Sigma wt.% 3.16 4.02 2.20 0.12 0.14 0.36 0.48

4. Conclusions Synthetic pigment AddCuPc is used in acrylic-based varnish for coloring various types of building materials (iron, wood, etc.). It was found that coloring materials containing AddCuPc pigment have a higher color brightness, reduced corrosion effects, as well as increased resistance to sunlight and high economic efficiency.

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and photo-electronic devices // Macroheterocycles. 2012. No. 5 (3). S. 191-202. [4] Erk P., Hengelsberg H. Phthalocyanine dyes and pigments // The porphyrin handbook. Netherlands: Elsevier Science, eds .: Kadish K. M., Smith K. M., Guilard R. 2003. V. 19. Ch. 119. P. 105-149 [5] Kadish K.M. The porphyrin handbook / K. M. Kadish, K. M. Smith, R. Guilard. - San Diego: Academic Press, 2003 .-- V.15-20. [6] de Diesbach H., von der Weid E. Quelques sels complexes des o ‐ dinitriles avec le cuivre et la pyridine // Helvetica Chimica Acta. - 1927. - T. 10. - No. 1. - S. 886-888. [7] Zheltov A. Ya., Perevalov VP. Fundamentals of the theory of color of organic compounds: textbook. allowance. M .: RCTU them. D.I. Mendeleev, 2012.347 s. [8] Process for the production of highly halogenated copper phthalocyanines: patent US3293262A; USA Ciba Geigy Corp .; 12/20/1966. [9] Tarasevich B.N. IR spectra of the main classes of organic compounds // Reference materials. Moscow 2012. From 4-47.