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546 CHEMICAL PROBLEMS 2019 no. 4 (17) ISSN 2221-8688_@
UDC 547.592.2+547.426.1+547.599.2
PREPARATION OF MONOCYCLIC DIESTERS OF GLYCEROL
Kh.M. Mamedova
Acad Y.H. Mamedaliyev Institute of Petrochemical Processes National Academy of Sciences of Azerbaijan, Khojaly Avenue, 30, Baku AZ 1025 (Azerbaijan) E-mail: kimyaci586@gmail.com
Received 12.10.2019
Abstract: The reaction of cyclohexene addition to glycerol in the presence of boron trifluorideetherate to obtain a simple cyclohexyl-2-glyceride ether was carried out. Also, the reaction of esterification of the obtained cyclohexyl-2-glyceride with C1-C5 monobasic saturated carboxylic acids in the presence of a heterogeneous catalyst KU-2-8 (H-form) was studied. The influence of various factors on the yield of cyclohexyl-2-glyceride and the ester formate obtained on its basis has been studied, and optimal reaction conditions have been found. As a result, appropriate esters with yields 71 -91% were obtained. Physicochemical properties of the synthesized esters were determined and their structure identified. Keywords: glycerin, cyclohexene, cyclohexyl glyceride, esterification, monocyclic diesters, formate
DOI: 10.32737/2221-8688-2019-4-546-550
Introduction
Over the past 20 years, there has been an unprecedented breakthrough in the biodiesel industry worldwide that led to an excess of glycerin. The growing demand for biodiesel has resulted in overproduction of glycerol to reduce commercial prices for glycerol [1]. Note that global growth in biodiesel production is expected to result in the production of more than 42 billion liters of crude glycerin by 2020 [2]. The traditional use of glycerin includes textiles (24%), food and drinks (21%), cosmetics and toiletries (18%), medicines (18%), tobacco (6%), paper and printing (5% ), etc. It is necessary to find new conversion routes for this chemical to avoid market saturation [3]. The main processes for the synthesis of glycerol ethers which are used as fuel additives, increase the octane number and improve the properties of gasoline, are esterification of glycerol with monohydric alcohols, as well as transesterification of esters and addition of unsaturated hydrocarbons [4, 5].
It has to be kept in mind that the esterification of glycerol with carboxylic acids leads to the preparation of mono-, di- and tri-esters of glycerol. Monoesters of glycerol can be also synthesized by transesterification of glycerides. Monoesters of glycerol and their derivatives are widely used as emulsifiers in the food, pharmaceutical and cosmetic industries [6-9].
In recent years, as a result of the addition of diols to bicyclic olefins, a number of cyclic ethers have been obtained and their properties studied [10]. It revealed that they have antiseptic properties and can be used for preparation of drugs to treat fungal diseases [11].
Continuing research in this area, we studied the preparation of monocyclic ether of glycerol in the presence of a homogeneous catalyst BF3*OEt2 and mixed diesters based on them, by reaction of addition C1-C5 monobasic saturated carboxylic acids to it.
CHEMICAL PROBLEMS 2019 no. 4 (17)
www.chemprob.org
Kh.M. MAMEDOVA
547
Scheme
CH2(OH)-CH(OH)-CH2(OH)
Oh Oh
r-cooh 4-8
KU-2-8*
O
O-CH2-CH-CH2_O-C-R
Oh
1 3
R=H (4, 9), CH3 (5, 10), C2H5
In the first stage the reaction of addition of glycerol to cyclohexene in the presence of a BF3*OEt2 catalyst was carried out. In order to find optimal conditions for the synthesis of cyclohexyl-2-glyceride, the influence of various factors on the yield of ether was studied.
When studying the effect of temperature on yield 3, it found that as the reaction temperature rises from 80 to 90 °C (t-2 h, BF3*OEt2 - 0.5%), the yield of cyclohexyl-2-glyceride grows as well - from 42 to 47%, while its further growth up to 100 ° C does not result in a significant increase in the yield of ether. At 90 °C, the effect of a molar ratio of reacting components of 1:2 in the range of 1:
1-1: 1.4 was studied to reveal that with their ratio of 1: 1.2, the highest ether yield is 51%.
The influence of the amount of catalyst on the formation of ether was studied in the range of 0.5-2%. The most effective amount of catalyst is 1.3%, so the amount of catalyst (t-2 h), the yield of cyclohexyl-2-glyceride is 55%.
The effect of the reaction time (2-6 h) on the yield of ether was also studied, and it has been found that the greatest yield is achieved with a reaction time of 4 hours
The optimal reaction conditions are as follows: temperature 90 °C, the molar ratio of the raw components 1: 2 = 1:1.2, the amount of catalyst BF3*OEt2 1.3 wt. %, reaction time 4 hours. The yield of ether 3 is 70%.
At the second stage of the studies, the reaction of esterification of obtained cyclohexyl glyceride with carboxylic acids in the presence of a heterogeneous catalyst KU-
2-8 (H-form) was carried out and 1,3-glycerol mixed diesters obtained.
To find the optimal conditions for the synthesis of cyclohexyl-2-glyceride-3-formate, the influence of the molar ratio of reacting components 3: 4 (1: 1-1: 2) and the amount of
9-13
(6, 11), n-C3H7 (7, 12), n-C4H9 (8, 13).
catalyst KU-2-8 (1-3%) influence on the yield of ether 9 was studied .
Studies revealed that a high yield of ester 9 was achieved with a 3: 4 molar ratio of 1: 1 to make up 65%, because with an excess of carboxylic acid, the number of by-products - triesters of glycerol increases resulting from the addition of a secondary hydroxyl group. The optimal amount of catalyst was considered to be 2.5 wt. %, with a further increase in its amount, the yield of ether does not increase significantly.
The reaction was carried out in benzene at a temperature of 80 °C with duration of the reaction which was determined through the termination of water release which is about 3 hours. The yield of ether 9 reaches 91%.
Under similar conditions, a catalytic addition of acetic 5, propionic 6, butyric 7, valerianic 8 acids to 3 was carried and appropriate diesters synthesized.
In the course of esterification of saturated acids with cyclohexyl-2-glyceride, along with basic product in the amount of 79%, mixed triesters of glycerol were obtained.
The purity of isomeric composition and the structure of the synthesized esters were
1 13
studied and proved using GLC, IR, and H, C NMR spectra. The purity of the esters, according to GLC analysis, is 98-99%.
In the IR spectra of the synthesized esters of cyclohexyl glyceride, along with intense absorption bands in the 2857-2932 (CH), 1450 (-CH2), there were intense absorption bands in the 1740 cm-1 (C=O) and 1229 cm-1 (-COO -) characterizing the presence of an ester group. Intense absorption bands in the 3380-3420 cm- 1 correspond to stretching vibrations of the OH group at the secondary carbon atom which are absent in the IR spectra of mixed triglycerides as byproducts of the reaction.
BF3 OEt2
548
PREPARATION OF MONOCYCLIC
13/
C NMR chemical shifts of carbon atoms of the carboxyl group are apparent in
the 160.87-165.24 ppm.
Experimental
IR spectra of the synthesized compounds were recorded on an "ALPHA iQ-FURYE"spectrophotometer by Bruker (Germany) while 1 H and 13 C NMR spectra were recorded on the "Bruker AV-300" with a frequency of 300 MHz (300 MHz) in acetone d6.
The composition and purity of the synthesized ethers, as well as the starting compounds, were determined by means of GLC analysis. The analysis was carried on a LKhM-8 MD chromatograph, column length 1.5 m, liquid phase 10 wt. % polyethylene glycol succinate on spherochrome, evaporator temperature 200-250 ° C, columns 120-150 ° C, detector current 100 mA, carrier gas helium, speed 45 ml / min.
d
Founded,%: C 61.97; H, 10.35. C9H18O3. Calculated,%: C 62.04; H 10.41.
Cyclohexyl-2-glyceride-3-formate (9). A mixture of 87 g (0.5 mol) of reagent 3, 23 g (0.5 mol) of formic acid, 50 ml of benzene and 4.4 g of KU-2-8 catalyst was heated at 80 °C for 3 h. 91.7 g (91%) compound 9 was isolated by vacuum distillation. B p. 145-146 ° C (8 mm Hg),
j20 20 ,
d4 1.1733, nD 1.4685. IR spectrum, v, cm-1: 1738 (C = O), 1225 (C-O-C), 1364 (CH3), 1448 (CH2), 2856-2931 (CH), 3414 (OH). 1H NMR spectrum, 5, ppm: 1.31-1.73 m (10H, 5CH2), 2.88 m (H, CH-O), 3.59-4.15 d (4H, 2CH2, J 10.9 Hz), 4.02 m (H, CH ), 3.55 s (H, OH), 7.85 d (H, HCOO, J 8.3 Hz). 13C NMR spectrum, 5C, ppm: 31.88 (C1,3), 82.08 (C2),
4,6\
Formic acid - b.p. 100.5 °C, d4 1.220, 23.7 (C4,6), 23.97 (C5), 72.0 (C7), 68.40 (C8)
nD 1.3714; acetic acid - b.p. 118.1 °C,
d 20 n 20
d4 1.049, nD 1.3698; propionic acid - b.p.
,720 20
141.4 °C,d 4 0.992, nD 1.3874; butyric acid -
.720 ,„20
b.p. 163.5 °C, d4 0.959, nD 1.3991; valerianic
20 20 acid - b.p. 186.4 °C, d4 0.939, nD 1.4086;
,720 20
BF3*OEt2- b.p. 126 ° C, d4 1.239, nD 1.308.
The physicochemical constants of the saturated acids coincided with published data [12].
Cyclohexyl-2-glyceride (3). A mixture of 82 g (1 mol) of reagent 1, 110.4 g (1.2 mol) of glycerol and 1.3 g (0.01 mol) of BF3*OEt2 catalyst was stirred for 4 hours at 80 ° C. The reaction mixture was washed with water, dried with magnesium sulfate and subjected to
vacuum fractionation. Yield 128.8 (70%), b.p.
20 20 180 °C (45 mm Hg), d 4 1.100, nD 1.4870.
IR spectrum, v, cm -1: 1740 (C = O), 1229 (C-
O-C), 1367 (CH3), 1450 (CH2 ), 2857-2932
(CH), 3412 (OH). 1H NMR spectrum, 5, ppm:
1.30-1.70 m (10H, 5CH2), 2.90 m (H, CH-O),
3.60 d (4H, 2CH2, J 10.9 Hz), 3.64 m (H, Ch),
3.55-3.60 s (2H, 2OH). 13C NMR spectrum,
5C, ppm: 32.23 (C1,3), 82.1 (C2), 24.2 (C 4,6X
25.88 (C5), 71.59 (C7), 69.0 (C8), 62.7 (C9).
67.91 (C9). 159.7 (C10). Founded,%: C 59.31; H, 8.91. C10H18O4. Calculated,%: C 59.39; H, 8.97.
Cyclohexyl-2-glyceride-3-acetate
(10). A mixture of 87 g (0.5 mol) of reagent 3, 30 g (0.5 mol) of acetic acid, 50 ml of benzene and 4.4 g of KU-2-8 was heated at 80 °C for 3 h. 92 g (85%) of the compound 10 were isolated by vacuum distillation. B.p. 150-152
.720 ,„20
°C (8 mm Hg), d4 1.1356, nD 1.4686. IR spectrum, v, cm-1: 1742 (C= O), 1230 (C-O-C), 1362 (CH3), 1452 (CH2), 2848-2929 (CH), 3410 (OH). 1H NMR spectrum, Ô, ppm: 1.291.70 m (10H, 5CH2), 2.83 m (H, CH-O), 3.484.21 d (4H, 2CH2, J 10.9 Hz), 4.18 m (h, CH ), 3.49 s (H, OH), 2.19 m (3H, CH3). 13C NMR spectrum, ÔC, ppm: 31.92 (C1,3), 79.00 (C2), 23.66 (C4,6), 25.69 (C5), 72.6 (C7), 68.4 (C8), 64.7 (C9). 169.3 (C10), 20.1 (C11). Founded,%: C 61.13; H, 9.25. C11H20O4. Calculated,%: C 61.09; H, 9.32.
Cyclohexyl-2-glyceride-3-propionate
(11). A mixture of 87 g (0.5 mol) of reagent 3,
37 g (0.5 mol) of propionic acid, 50 ml of
benzene and 4.4 g of KU-2-8 was heated at 80
°C for 3 h. 73.4 g (64%) of the compound 11
was isolated by vacuum distillation. B.p. 159,720 20
161 °C (8 mm Hg), d4 1.0961, nD 1.4687. IR
Kh.M. MAMEDOVA
549
spectrum, v, cm -1: 1730 (C = O), 1212 (C-O-C), 1358 (CH3), 1433 (CH2), 2860-2932 (CH), 3380 (OH). 1H NMR spectrum, S, ppm: 1.361.69 m (10 H, 5 CH2), 2.79 m (H, CH-O), 3.39-4.08 d (4H, 2 CH2, J 10.9 Hz), 4.10 m (H, CH), 3.50 s (H, OH), 2.29 s (2H, CH2), 1.04 t
(3H, CH3, J 7.1 Hz). 13C NMR spectrum, SC,
ppm: 31.8 (C1,3), 80.2 (C2), 24.1 (C4,6), 25.73 (C5), 72.48 (C7), 69.2 (C8), 64.6 (C9), 169.9 (C10), 26.3 (C11). 8.2 (C12). Founded,%: C 62.61; H, 9.57. C12H22O4. Calculated,%: C 62.58; H, 9.62.
Cyclohexyl-2-glyceride of butyric acid (12). A mixture of 87 g (0.5 mol) of cyclohexyl-2-glyceride, 44 g (0.5 mol) of butyric acid, 50 ml of benzene and 4.4 g of KU-2-8 was heated at 80 ° C for 4 h. 88 g (72 %) of compound 12 were isolated by vacuum
d20
ppm: 31.92 (C1,3), 79.53 (C2), 23.91 (C4.6), 26.5 (C5), 72.2 (C7), 68.3 (C8), 63.98 (C9), 172.3 (C10), 35.60 (C11), 17.5 (C12), 12.8 (C13). Founded,%: C 63.83; H, 9.85. C13H24O4. Calculated,%: C 63.90; H, 9.90.
Cyclohexyl-2-glyceride of valerianic acid (13). A mixture of 87 g (0.5 mol) of cyclohexyl-2-glyceride, 51 g (0.5 mol) of n-valerianic acid, 50 ml of benzene and 4.4 g of KU-2-8 was heated at 80 ° C for 4 h. 91 g (71%) of compound 13 was isolated by vacuum distillation. B.p. 178-179 °C (8 mm
J20 20
Hg), d 4 1.0586, nD 1.4709. IR spectrum, v, cm -1: 1735 (C = O), 1223 (C-O-C), 1360 (CH3), 1448 (CH2), 2849-2930 (CH), 3380 (oh). 1H NMR spectrum, S, ppm: 1.30-1.71 m (10H, 5CH2), 2.80 m (H, CH-O), 3.50-4.03 d (4H, 2CH2, J 10.9 Hz), 4.13 m (H, CH ), 3.55 s (H, OH), 2.30 s (2H, CH2), 0.80 t (3H, CH3,
distillation. B.p. 169-170 °C (8 mm Hg), 1.0735, nDD 1.4696. IR spectrum, v, cm"1: 1732 J 71 Hz), i^213 m (4H, 2CTW. NMjR
(C = O), 1217 (C-O-C), 1363 (CH3), 1456 (CH2), 2863-2935 (CH), 3420 (OH). 1H NMR spectrum, S, ppm: 1.38-1.63 m (10H, 5CH2), 2.85 m (H, CH-O), 3.40-4.11 d (4H, 2CH2, J 10.9 Hz), 4.15 m (h, CH ), 3.53 s (H, OH), 2.32 s (2H, CH2), 0.85 t (3H, CH3, J 7.1 Hz), 1.79 m (2H, CH2). 13C NMR spectrum, SC,
spectrum, SC, ppm: 32.88 (C1,3), 81.3 (C2), 24.18 (C4,6), 25.6 (C5), 71.9 (C7), 69.4 (C8), 64.18 (C9), 171.8 (C10), 32.52 (C11), 26.3 (C12), 20.8 (C13), 12.9 (C14) Founded,%: C 65.12; H 10.08. C14H26O4. Calculated,%: C 65.08; H 10.14.
Conclusion
Bu using the reaction of esterification in the cyclohexyl-2-glyceride, formic, acetic,
presence of a heterogeneous catalyst KU-2-8 (H-form) monocyclic glycerol ether-cyclohexyl-2-glyceride was synthesized. Mixed diesters of glycerol based on
propionic, butyric and valerianic acids were also obtained, which are transparent viscous liquids and that can be used as additives to synthetic oils.
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QLiSERÎNiN MONOTSiKLiK QURULU§LU DiEFiRLORiNiN SiNTEZi
X.M. Mzmmzdova
AMEA akademik Y.H.Mammadaliyev adina Neft-Kimya Proseslari institutu AZ1025, Baki §., Xocali pr.30; e-mail:kimyaci586@gmail.com
BF3O(C2H5)2 katalizatorunun içtirakinda qliserinin tsikloheksena birla§ma reaksiyasi tadqiq olunmuç, naticada tsikloheksil-2-qliserid sada efiri sintez edilmiçdir. Sintez olunmuç tsikloheksil-2-qliseridin C1-C5 birasasli karbon turçulari ila heterogen КУ-2-8 (H formada) katalizatorunun içtirakinda efirlaçma reaksiyasi da öyranilmi^dir. Tsikloheksil-2-qliseridin va qliserinin diefirlarinin çiximina müxtalif faktorlarin tasiri tadqiq olunmuç va reaksiyanin optimal çaraiti tapilmiçdir. Naticada 71-91% çiximla diefirlar sintez olunmuç, fiziki-kimyavi xassalari tayin olunaraq, quruluçlari taseiq edilmiçdir. Açar sözfor: qliserin, tsikloheksen, tsikloheksilqliserid, monotsiklik diefirlar, efirlaçma, formiat.
ПОЛУЧЕНИЕ МОНОЦИКЛИЧЕСКИХ ^ДИЭФИРОВ ГЛИЦЕРИНА
Х.М. Мамедова
Институт Нефтехимических Процессов им. Ю.Г. Мамедалиева Национальной АН Азербайджана, AZ1025 Баку, пр.Ходжалы, 30; e-mail: kimyaci586@gmail. com
Проведено присоединение глицерина к циклогексену в присутствии эфирата трехфтористого бора BF3 O(C2H5)2 с получением простого эфира циклогексил-2-глицерида. Изучена также реакция этерификации полученного циклогексил-2-глицерида С1-С5 одноосновными насыщенными карбоновыми кислотами в присутствии гетерогенного катализатора КУ-2-8 (Н-форма). Для получения целевого продукта с максимальным выходом изучено влияние различных факторов на выход циклогексил-2-глицерида и сложного эфира - формиата, полученного на его основе, и найдены оптимальные условия реакции. В результате были получены соответствующие эфиры с выходами 71%-91%. Определены физико-химические свойства синтезированных эфиров и доказано их строение.
Ключевые слова: глицерин, циклогексен, циклогексилглицерид, этерификация, моноциклические диэфиры, формиат
