Synthesis of nitrogen-containing phenolformaldehyde oligomers , grafted with vegetable oils

Synthesis of nitrogen-containing phenolformaldehyde oligomers (phfo), grafted with vegetable oils is aimed at the acquisition of new range coating materials. Oil has been used as an example of soybean and linseed oils. The interaction between phfo and vegetable oil is carried out by means of functional groups as result of the oxidation prosesses on carbon atoms adjacent to the double bond and the functional groups,including oligomer macromolecules. Physicalchemical properties of nitrogen-containing as result of modification by means of benzoguanamine (bga) monoalkyl (C8-C12)phfo, grafted with soybean oil is reflected. The probable structure of the nitrogen-containing monoalkyl(C8C12)phfo, grafted with soybean oil has been studied by means of NMRand IR-spectroscopy methods. The mechanism of the occurrence of first and second stages of the process are described.


Introduction
Obtaining of coating materials by means of oxidation of vegetable oils and their using as mixture with some resins are known.The solution of the end product of their interaction or their mixture with variety resins in organic solvents (oil paints) are used. Thus, vegetable oils in the main are the ethers of glycerol with unsaturated carboxylic acids, and double bonds play an active role in the oxidation process: the displacement (isomerization) of double bonds, oligomerization of triglycerides, formation of additional functional groups have taken place and they play a positive role in the process of solidification. One of these resins are policondensation product of phenol and its derivatives with formaldehyde.
There are water-soluble coating materials among the phenolic resins [1],grafted with vegetable oilsphenolic oligomers, grafted with soybean oil, which keeps the boron,varnishes and enamels resistant to gasolineor modified with linseed oil, rosin and only tallowy oil-it is important too [2]. Compounds of this range have been applied as well as highquality lubricants. Chinese scientists synthesized phfo, modified with linseed oil, which thermal resistance differs from [3][4][5].
Presented in this article synthesis of nitrogen-containing phfo, grafted with vegetable oils is aimed at the acquisition of new range coating materials. In general, in order to obtain of coating materials the higher the cost of known synthetic resins are to be partially replaced with cheaper vegetable oils. These paints are non-polar solvents (solvent, uayt-spirit) to be the solution, with the superior brightness and high physical-mechanical properties.

Experimental
Oil has been used as an example of soybean and linseed oils. Preference is given to the selection of these oils in their unsaturation. As is well known, the interaction between phfo and vegetable oil is carried out by means of functional groups as result of the oxidation prosesses on carbon atoms adjacent to the double bond and the functional groups,including oligomer macromolecules, that is why the higher amount of the double bonds has an positive impact on the process. In the following table (Table 1) the composition of used vegetable oils and their physical-chemical parameters, known literature [6] is reflected.

Table 1. Composition and physical-chemical characteristics of vegetable oils
As can be seen from the table, the physical-chemical properties of oils are also close to each other,the composition varies considerably, both amount of unsaturated fatty acids of soybean and linseed oils, as well as the diverse range. These oils have a lower freezing temperature associated with it. Monoalkyl(C8-C12)phfo of novolac type was synthesized by known metod in molar ratio of alkylphenols and formaldehyde 1:0,85, at 98-1000С temperature and acidic medium (pH=3) over a period of 3-4 hours duration. 0,1-0,3 mol bga, bad or kad to 1 mol phenol compound were used as a modifier.

Indicators
On the second stage the prosess of interaction between synthesized products and vegetable oil have been studied. For the purpose, oligomers and vegetable oils 1: 3, 1:1, 3:1 ratios by weight of soybean and linseed oil samples were taken. To avoid premature gelatination, part of oligomer (about half) is dissolved in oil sample in 1 hour, the temperature was raised up to 1900C , then add the rest of oligomer mass and was mixed during 3-4 hours at the temperature 230-2500C. The final product is in the form of brown-colored viscous mass. Practices were carried out in air environment, but also to determine the effect of oxidation process in an inert (nitrogen ) atmosphere. The material balance data of processes in the first and second phases are presented in Table 2. The final products do not undergo any external change during the period of 5-6 months of storage. They are smooth and homogeneous and mostly in the form of brown-colored mass.
It should be noted that the final product yield is 98-100% taking into account the loss of the process at the level of practice error.
At the initial phase of the study, it was determined, that 1. Oxygen environment is necessary for the interaction of components; 2. Using of the modifiers with nitrogen-containing functional groups has a positive effect to the application of the products.
It should be noted that the natural triglycerides (glycerine esters on base of saturated and unsaturated one-atomic higher fatty acids) makes up ~95-98% of vegetable oils, but the rest of 2-5% consist of free fatty acids (~1-2%), phosphatideslecithin, kefaline and inosinphosphatides (~0,05-3 %), sterin, phytosterins (~0,3-0,5 %), pigments and vitamine E (~0,5 %) respectively. However, this is a very small amount of impurities, which do not adversely affect performance of the application properties of final product as coating, that is why their separation experiments are not performed and raw vegetable oil is used. According to the choice of vegetable oils, soybean and linseed oils, keeping the more unsaturated acid residue fragments were preferred (these fragments are important to facilitate of hardening and drying of coating materials). But a significant difference in the results of these oils is not observed, that is why for practical work soybeen oil was used. As known, the presence of high amounts of linolenic acid residue in composition of coating material leads to get yellow of them over time.
Physical-chemical properties of nitrogen-containing as result of modification by means of bga monoalkyl(C8-C12)phfo,grafted with soybean oil is reflected in Table 3.
As can be seen from the table, the synthesized oligomers unlimited dissolve in the non-polar solvents, such as solvent, uayt-spirit and so on. As known phfo" s don"t dissolve in non-polar solvents. Moreover, on the second stage at the fixed amount of bga the weight part increase of oligomer from 25% to 75% (example 3-5, 6-8, 9-11) kinematic viscosity acquires high prices and the temperature of softening is determined for the samples richer oligomer. The judgment compared to a fixed rate of oligomer:oil at the second stage and the molar quantity of nitrogen-containing modifier from 0,1 moles to 0,3 moles (example 3→6→9, 4→7→10, 5→8→11). Thus, viscousity indicators are increased.
The probable structure of the nitrogen-containing monoalkyl(C8-C12)ffo, grafted with soybean oil has been studied by means of the NMR-Fourier spectrometer ("Bruker" company, Germany) frequency of 300 MHz. Chemical shifts of atomic groups, related to soybean oil and the initial oligomer have been found in the spectrogram of the final product ( Figure 1). The structure of the nitrogen-containing monoalkyl(C8-C12)phfo, grafted with soybean oil has been studied by means of the IR-Fourier spectrometer ALPHA ("Bruker" company, Germany). Spectral-kinetic investigation was carried out in order to study the mechanism of the process. IR-spectrogram, both the initial components (the nitrogen-containing monoalkyl(C8-C12)phfo, obtained at the first stage and soybean oil), and the sample of the reaction mixture, obtained from their interaction during the interval of ~ 0.5 hours at the second stage, were recorded and compared. The following absorption bands in the spectrogram of initial oligomer are presented: 750 sm-1 -methylene group vibrations, 1370 sm-1 deformation (def.) and 2872 sm-1 valence (val.) C-H bonds of methyl groups, 1456 sm-1 (def.) and 2957 sm-1 (val.) C-H bonds of methylene groups, 1508 sm-1 (def.) and 3027,3060 sm-1 (val.) C-H bonds of the benzene nucleus, 1602 sm-1 (val.) C = C bonds of the benzene nucleus, 783,823,878 sm-1 (def.) C-H bonds of alkyl substitute of benzene nucleus, 1235 sm-1 (def.) and 3307 sm-1 (val.) OH bond vibrations, 1012 sm-1 (def.) O-H bonds of the alcohol groups, 953, 1543 sm-1 (def.) absorption bands corresponding to the NH bond. Except absorption bands in the IR spectrogram of the mixture of nitrogen-containing monoalkyl(C8-C12)ffo with soybean oil (reaction started), valent vibration of C = O bond of ester fragments -1743 sm-1, as well as absorption bands corresponding to the C = C bonds,which are characteristic for alkene fragments of esters in accordance with the intensity 1651 and 3008 sm-1 are observed in spectrogram of the final product (fiqure 2).

Figure 1. The NMR-spectrogram of the nitrogen-containing monoalkyl(C8-C12)phfo, grafted with soybean oil
Presented below in table 4 and 5, the optical density change of the main functional groups in dependence on the duration of the reaction were expressed: C = O (1720,1743 sm-1),C = C (1651,3008 sm-1),the phenol OH (1235 sm-1),NH (1543 sm-1) and the alcohol, in other words, the metilol group -CH2OH fragments (1012 sm-1). For comparison, the soybean oil (Table 4) and the initial nitrogen-containing monoalkyl(C8-C12)ffo (Table 5) were taken. J u n e 1 9 , 2 0 1 5   After 3,0 hour 0,105 0,014 0,017 J u n e 1 9 , 2 0 1 5 As can be seen from table 4, 1) that the absorption bands indicating the intensity of double bonds in soybean oil are almost unchanged over time, it confirms that the double bonds not spent during the process; 2) carbonyl groups, which included the ester fragments had not been spent, but the new carbonyl groups, which amount ~ is close to amount of these fragments (1720 sm-1) were found. Thus, during the high-temperature oxidation of triglycerides in soybean oil, the formation of new carbonyl group fragments is observed. The optical density of these groups, formed at the first hour of the process is almost constant and remains unchanged up to the end; 3) from the Table 5 is clearly visible that the optical density of the phenolic OH functional groups and the NH fragments is not change over time; 4) the observed ~ 4-fold decrease in the indices of optical density of methylol -CH2OH groups (at 1012 sm-1) indicates that these groups have been used in the process.

RESULTS
Taking into account the change in the amount of functional groups of soybean oil fragments and oligomer makromolekules, interaction is completed within ~ 2 hours, as well as allows to say that there is no need to spend superfluous time and energy. Analyzes of the results at the second stage indicates that an interaction has happened between themethylol groups of oligomer makromolekules and new functional groups (-OH,-OOH, etc.) of triglyceride fragments of the soybean oil, arising from the oxidation. Taking into account all these, the mechanism of the occurrence of first and second stages of the process are as follows: I. Synthesis of initial oligomers.