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17SYNTHESIS OF ACETYLENIC DIOLS BASED ON ACETYLENIC ALCOHOLS
Juraboev Fozil Mamasolievich
Doctor of Philosophy (PhD) in Chemical Sciences, Namangan Institute of Engineering and Technology, Republic of Uzbekistan, Namangan city https://doi.org/10.5281/zenodo. 7237916
Abstract: This article examines the influence of various factors on the performance of the main product in the synthesis of acetylene diols based on direct condensation of acetylene alcohols with aldehydes and ketones.The influence offactors such as the structure and nature of acetylene alcohols on the yield of acetylenediols, the composition and nature of carbonyl compounds, temperature, catalyst, reaction duration has been studied.
Keywords: secondary acetylenic alcohol, tertiary acetylenic alcohol, acetylene diols, 2-methylbutyn-3-ol-2, hexyne-1-ol-3, oil aldehyde, acetone, methylethyl ketone, alkaline medium, decyn-5-diol-4.7, 3-methylnonyn-4-diol-3.6, IR-spectroscopy.
СИНТЕЗ АЦЕТИЛЕНОВЫХ ДИОЛОВ НА ОСНОВЕ АЦЕТИЛЕНОВЫХ
СПИРТОВ
Аннотация: В данной статье рассмотрено влияние различных факторов на показатели основного продукта синтеза ацетилендиолов на основе прямой конденсации ацетиленовых спиртов с альдегидами и кетонами.Влияние таких факторов, как строение и природа ацетиленовых спиртов на изучены выход ацетилендиолов, состав и природа карбонильных соединений, температура, катализатор, продолжительность реакции.
Ключевые слова: вторичный ацетиленовый спирт, третичный ацетиленовый спирт, ацетилендиолы, 2-метилбутин-3-ол-2, гексин-1-ол-3, масляный альдегид, ацетон, метилэтилкетон, щелочная среда, децин-5-диол-4,7, 3-метилнонин-4-диол-3.6, ИК-спектроскопия.
INTRODUCTION
It is known that among the organic compounds that have retained the acetylene bond in their molecule, acetylene diols stand out for their high biological activity. Due to the fact that the molecule of such compounds contains acetylene bonds and two hydroxyl groups, that is, it has several reactively active centers, it is widely used in the oil and gas industry as inhibitors, biostimulators, herbicides in agriculture.
Acetylene diols are synthesized by the Favorsky reaction based on acetylene and carbonyl compounds. But in this method, the yields of acetylene diols are somewhat lower, and also, the isolation of acetylene diols from a mixture of acetylene alcohols and the resulting diols creates some complexity. In this regard, the possibility of synthesis of some acetylenediols, which were not presented in the literature, on the basis of secondary and tertiary acetylene alcohols and carbonyl compounds was investigated in this work.
MATERIALS AND METHODS
Acetylene diols can be synthesized in an alkaline medium by direct condensation of acetylene alcohols with aldehydes and ketones. In this case, at low temperatures, that is, at -10, -20 oC, the yields of acetylene diols are low (20 - 30 %), while at +20oC with an increase in temperature, the yields of the product reach 30 - 40%, but when the temperature rises to +20 oC, additional products are formed as a result of aldol condensation of aldehydes and ketones in an alkaline environment. The resulting mixture is difficult to separate from each other. Secondary-
secondary and secondary-tertiary acetylene diols based on hexyn-1-ol-3, 2-methylbutyn-3-ol-2 and 3-methylpentyn-1-ol-3 were synthesized [6-9]. The reaction scheme is as follows:
C3HTCH(OH)C=CH + R-CO-R-► C3HTCH(OH)C=CCH(OH)RRi
Where: I. R1 = -H; R = -C3H7; II. R=RI= -CH3; RI= -C2H5.
As a result of the reaction carried out with hexin-1-ola-3 oil aldehyde and corresponding ketones at a temperature from -5 ° C to +20 °C, the yield of their secondary-secondary alcohols (59.2% at a temperature of 10 °C) was higher than that of their secondary-tertiary acetylene alcohols (71.2% at a temperature of 20 °C). Having reached optimal conditions for the synthesis process, the ratio AA : KOH = 1:3, the temperature from +10 oC to +20 oC, the reaction duration was set to 3 hours. The flour content in the main product drops sharply at a temperature of +30 °C (47.2%). The reason for this is the formation of additional products as a result of spontaneous condensation of aldehydes and ketones.
The effect of temperature and reaction duration on the yields of the obtained decyn-5-diol-4.7 and 3-methylnonyn-4-diol-3.6 is presented in Tables 1 and 2.
Table 1
The effect of temperature on the yield of the product during the synthesis of decyn-5-
diol-4,7
Reaction duration, hour Product output, % Average reaction speed
% / hour mol/liter./hour
Temperature, -5 °C
1 13,2 13,20 0,75
2 23,9 11,95 0,68
3 30,2 10,73 0,62
4 38,5 9,62 0,55
Temperature, 0 °C
1 21,4 21,40 1,23
2 36,3 18,15 1,04
3 49,2 16,40 0,94
4 53,9 13,47 0,77
Temperature, +10 °C
1 31,0 31,00 1,79
2 46,4 23,20 1,34
3 59,2 19,73 1,14
4 59,4 14,85 0,86
Temperature, +20 °C
1 32,5 32,50 1,88
2 40,6 20,30 1,17
3 41,2 13,73 0,79
4 42,1 10,52 0,61
RESULTS AND RESULTS
As can be seen from the results obtained, during the synthesis of decyn-5-diol-4.7, the yield in the main product increases from 28.5% to 59.4% in the range from -5 °C to 10 °C. But at 20 °C,
the yield decreases to 42.1%. The reason for this is that at high temperatures, the aldehyde condenses by itself to form oxy-aldehydes.
Table 2
The effect of temperature on the yield of the product during the synthesis of 3-
metylnonyn-4-diol-3,6
Reaction duration, hour Product output, % Average reaction speed
% / hour mol/liter./hour
Temperature, -5 °C
1 9,2 9,20 0,51
2 16,1 8,05 0,54
3 20,2 6,73 0,37
4 23,5 5,87 0,32
Temperature, 0 °C
1 17,4 17,40 0,96
2 24,2 12,10 0,67
3 28,6 9,53 0,53
4 30,7 7,67 0,42
Temperature, +10 °C
1 22,5 22,50 1,24
2 36,0 18,00 0,99
3 43,6 14,53 0,80
4 46,4 11,6 0,64
Temperature, +20 °C
1 32,0 32,00 1,77
2 52,1 26,05 1,44
3 72,6 24,20 1,34
4 72,7 18,17 1,00
Temperature, +30 °C
1 38,8 38,80 2,15
2 45,1 22,55 1,25
3 47,2 15,73 0,88
4 47,0 11,75 0,65
During the synthesis of 3-methylnonyn-4-diol-3,6, the same situation as above is repeated, that is, at a temperature of -5 °C, the reaction rate decreases to 72.7% after 20 °C, while the reaction rate is 9.2%, this situation is also explained by condensation, as indicated above.
Consequently, in the chosen method, aldol condensation based on aldehyde during the synthesis of acetylenediols begins at a lower (20 ° C) temperature than condensation based on ketones.
The structure of the obtained acetylenediols was confirmed by IR and NMR spectra. According to the results of the experiment, three acetylene diols were synthesized. Two of them are secondary-tertiary acetylene diodes, which are not listed in the literature. Some physico-chemical constants of the obtained products are presented in Table 3.
Table 3
Yields and some physico-chemical constants of synthesized acetylene diols
Index
Compound name and structural formula Gross formula Yield, % Boiling point, X Density (g/sM3) refractio n n ± 0,003
Decyn-5-diol-4,7 C3H7CHC=CCHC3H7 C10H18O2 45-60 195/197/7 6 0,9621 1,4710
OH OH
2-methyloctyn-3-diol-3,5 C3H7CHC=CCH(CH3)2 C9H16O2 42-75 139/141/3 8 0,9398 1,4520
OH OH
3-methylnonyn-4-diol-3,6 C3H7 CHC=CCH(CH3)C2H5 C10H18O2 43-73 158/160/3 8 0,9472 1,4625
OH OH
Valence fluctuations of methyl and methylene groups in the IR spectrum of decyn-5-diol-4.7 are manifested in the range of 3000 - 2800 cm-1, -C-O-groups 1150 - 1000 cm-1. Deformation fluctuations of the acetylene bond (-C-C-) are not visible in the region of 2130-2080 cm-1. This is explained by the fact that symmetrical functional groups are located on each side of the acetylene bond. Absorption lines of hydroxyl groups forming an internal molecular hydrogen bond in the molecule are manifested in the areas of 3600 - 3120 cm-1, methyl-, metin-, and absorption lines of methylene groups in the areas of 1320 cm-1, 1450 cm-1, 1390 cm-1.
Protons (6H) of the methyl group in the 1H-NMR spectrum of Trans-decyne-5-diol-4,7 are 0.78-0.98 m.d., proton (8H)of the methylene group is 1.2-1.7 m.d. proton in the form, 4.24.4 m.d. of a proton (2H)of the hydroxyl group, 4.58-4.69 m.d., proton (2H) in the form of the metin group, observed in the field. In the Cis isomer, however, a shift of 4.22-4.32 m.d. was observed.
The use of acetylene diols. In field experiments, the effect of synthesized acetylene diols on biostimulating properties on the growth, development and productivity of cotton was studied, the results are presented in Table 2.
Table 2
The effect of acetylene diols on the growth, development and productivity of cotton
№ Experience options Plant stem height, cm The average number of boxes in one cotton bush Average weight of a cotton box, g Average weight of cotton in one cotton bush Yield, c/ha Additional yield, c/ha
1 Control (water) 104,2 10,1 4,9 49,5 39,6 -
2 0.002% solution decyn-5-diol-4,7 105,5 10,6 5,3 56,18 44,9 5,3
3 0.002% solution 2-metyloctyn-3-diol-3,6 104,9 10,7 5,2 55,6 44,5 4,9
4 0.002% solution 3-metyknonyn-4-diol-3,6 104,7 10,4 5,3 55,1 44,1 4,5
From the results of the field experiments obtained, it becomes clear that the synthesized acetylenediols - decyn-5-diol-4,7, 2-methyloctyn-3-diol-3,6 and 3-methylnonyn-4-diol-3,6 are active biostimulants, the use of which has an effective effect on the growth of cotton, germination of cotton seeds, thanks to which it is possible to achieve increasing the yield of cotton per hectare by 4.5-5.3 hundredweight.
The experimental part. Synthesis of 2-methyloctin-3-diol-3,5. 9,8 g (0,1 mol) hexyn-1-ol-3 and 16,8 g (0,3 mol) of crushed powdered potassium hydroxide and 100 ml of absolute diethyl ether is placed in a 250 ml three-neck flask equipped with a thermometer, mixer and a funnel-dropper, rotating cooler. The reaction mixture is cooled with a mixture of ice and table salt and stirred for 30-35 minutes. 5,8 g (0,1 mol) of dimethyl ketone dissolved in 40 ml of absolute diethyl ether is dripped into the resulting suspension and added for 4 hours. After stopping the reaction, the reaction mixture is left overnight. The next day, the reaction mixture is diluted with cooled 50 ml of distilled water, the product is hydrolyzed. Then the ether layer is separated using a separator funnel, and the aqueous layer is extracted at least three times with diethyl ether (50 ml each). The essential layers are combined, first washed with 20 ml of 10% acetic acid solution, then distilled water, and then dried using freshly purified potassium carbonate. The ether layer that holds the main product is removed in a water bath and diethyl ether is isolated. The main product is distilled under vacuum conditions, the colon is cleaned chromatographically.
In the same way, 3-methylnonyn-4-diol-3,6 and decyn-5-diol-4,7 are synthesized on the basis of 2-methylbutyne-3-ol-2 and hexyne-1-ol-3.
CONCLUSION
During the synthesis of acetylene diols, it was found that secondary-tertiary acetylenediols are formed with a higher yield than secondary-secondary acetylenediols, and the mechanism of the reactions was theoretically justified by quantum chemical calculations of the reactivity of substances.
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