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20Выводы. 1) Предложен один из способов получения основ смазочных масел путем модификации как самих растительных масел путём введения в молекулы его жирных кислот дополнительных функциональных групп. Вязкость получаемых продуктов регулируется благодаря изменению времени реакции хлорирования и переэтерефикации.
2) Рассмотрены варианты присадок растительной природы для повышения вязкости продукта. Полученные данные свидетельствуют о достаточно невысокой способности фосфолипидов, мыл хлорированного масла и продуктов полимеризации подсолнечного масла, в качестве присадок для повышения вязкости бутиловых эфиров жирных кислот.
3) Исследовано влияния продуктов полимеризации масел на вязкость гидроксилированных бутиловых эфиров жирных кислот подсолнечного масла. Эта добавка показала свою перспективность для повышения вязкости полученной основы смазочного масла.
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ETHANOL CONVERSION INTO ACETONE OVER MAGNESiUM-ZINC OXIDE CATALYSTS
Taghiyeva T.
PhD Student, Chemical technology faculty, Azerbaijan State Oil and Industry University, Baku, Azerbaijan
Baghiyev V.
Doctor of chemical science, Professor, Chemical technology faculty, Azerbaijan State Oil and Industry University, Baku, Azerbaijan
Abstract
The reaction of ethanol conversion on a number of binary Mg-Zn-O catalysts was studied. It was shown that the main reaction product of ethanol conversion on the studied catalysts is acetone. By products of ethanol conversion reaction are acetic aldehyde, carbon dioxide, and ethylene.
Keywords: ethanol conversion, acetone, binary catalysts, zinc oxide, magnesium oxide.
Introduction
Acetone is one of the most important monomers widely used in the petrochemical industry. One of the methods for producing acetone is the reaction of vapor-phase conversion of ethanol. In this case, parallel reactions can occur simultaneously with the formation of ethylene, acetic aldehyde and ethyl acetate [1,2]. The
increase in the yield of one of these compounds depends on the selectivity of the catalyst. From the periodic literature it is known that zinc-containing catalysts selectively increase rate of the reaction of the conversion of ethanol to acetone [1,3]. In this connection this work is devoted to studying the reaction of the conversion of ethanol to acetone on binary magnesium-zinc oxide catalysts.
Experimental
Magnesium-zinc oxide catalysts were prepared by co-precipitation of aqueous suspensions of magnesium carbonate and zinc carbonate. The mixture was evaporated at 95-100°C, dried at 100-120°C and calcined for 10 hours at 700°C. The activity of the synthesized catalysts was studied on a flow-through installation unit with a quartz reactor in the temperature range of 250-700°C. 5 ml of the studied catalyst with a grain size of 1.0-2.0 mm was loaded into the reactor and its activity was studied in the reaction of ethanol conversion. The yields of the ethanol conversion products, as well as the
120
ethanol conversion, were determined on a chromatograph with a flame ionization detector and 3 m long column filled with specially treated Polysorb-1 sorbent. The amount of formed carbon dioxide was determined on a chromatograph with a 6 m column filled with a celite sorbent coated with Vaseline oil.
Results and discussions
Conducted research have shown that the main reaction product is acetone and acetic aldehyde. Other products, such as ethylene and carbon dioxide, are also observed. The study of the effect of temperature on the reaction of ethanol conversion on binary magnesium-zinc oxide catalysts it is shown on figure 1.
100
2 £
80
60
40
20
CO2 C2H4 CH3CHO CH3COCH3 —Conversion
200 300 400 500
Temperature, °C
600
Fig. 1 Effect of temperature on the yields of reaction products of ethanol conversion.
Obtained results show that ethanol conversion reaction on binary magnesium-zinc oxide catalysts begins at 250°C. At this temperature, a small amount of acetaldehyde (1.2%) is obtained. A further increase in the reaction temperature leads to an increase in acetic aldehyde and the formation of other reaction products. The highest yield of acetaldehyde is achieved at 350°C and is equal 16.4%. With increasing temperature, the yield of acetone also passes through a maximum. The maximum yield of acetone is observed at 450°C and is equal 68.7%. It was also found that the conversion of
The conversion of ethanol to binary magnesium-
ethanol sharply increases with increasing reaction temperature and at 550°C almost reaches 100%. Such dependences were obtained for all binary magnesium-zinc oxide catalysts.
We found that the activity of Mg-Zn-O catalysts in the conversion of ethanol to acetone also depends on the atomic ratio of magnesium to zinc in the composition of the binary catalyst. Below in the table 1 it is shown the effect of the atomic ratio of magnesium to zinc on the activity of the studied catalysts.
Table 1
Reaction products The yields of reaction products in % on samples with different atomic ratios of magnesium to zinc
1:9 2:8 3:7 4:6 5:5 6:4 7:3 8:2 9:1
CO2 10,7 15,3 11,3 11,3 7,2 8,1 7,9 5,3 4,7
C2H4 4,3 5,3 10,1 7,6 9,4 13,4 15,3 12,7 9,4
CH3CHO 3,1 5,7 4,1 3,6 4,5 16,2 9,8 13,7 16,6
CH3COCH3 68,7 62 59,8 55,8 48,7 36,9 30,7 16,9 6,4
Ethanol conversion 88,8 89,5 90,8 79,9 78,9 71,5 69,3 58,3 53,5
0
As can be seen from the table 1, the yield of acetone with an increase in the content of magnesium oxide in the composition of the catalyst passes through two maxima on the samples Mg-Zn=4-6 and Mg-Zn = 7-3. The yield of acetic aldehyde increases with increasing magnesium content in the composition of the catalyst and on the sample Mg-Zn = 9-1 is equal 16.6%. The table also shows that with an increase in the content of magnesium oxide in the composition of the catalyst, the graph of the dependence of ethylene yields on the composition has the form of a curve with two maxima, while the yield of carbon dioxide decreases slightly with increasing magnesium content in the composition of the catalysts.
Thus, based on the obtained results, it can be said that binary catalysts based on magnesium oxide and zinc have high activity in the reaction of the conversion of ethanol to acetone. It was found that the catalyst with the composition Mg-Zn =4-6 is most active in the reaction of acetone formation. The yield of acetone on this catalyst is equal 67.8%.
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