SCIENCE & INNOVATION

CATALYTIC CONVERSION OF DIMETHYL ETHER TO ETHYLENE AND PROPYLENE

Bukharov A.Q., Elamonova N.A., Faizullaev N.I., Rahmatov Kh.B.

In this work, the results on the creation of highly efficient catalytic systems with new content modified with various elements are summarized. At the same time, the effect of the nature of the modifying element, as well as the high-temperature treatment with water vapor, on the texture, acidic characteristics and catalytic properties of the zeolite catalyst in the conversion of dimethyl ether to ethylene and propylene was considered. In order to increase the stability of the Mg-Zn-Zr-B/YuKTs catalyst, it was proved that unmodified Mg-Zn-Zr-B/YuKTs exhibited high activity when it was modified with P and Fe and used in the synthesis of ethylene and propylene from methanol and dimethyl ether. In the work, the catalytic conversion of dimethyl ether to ethylene and propylene was carried out on the Mg-Zr-Zn-B-YuKTs catalyst under the following optimal conditions: (T = 340 oC, R = 0.1 MPa, Var = 1000-2000 h-1. Raw materials: DME (15%) ÷ N2(85%). In the case of modification of zeolite catalysts containing zirconium and magnesium with B, it was proved that in almost all cases, an increase in the selectivity for C2-C4 ethylene and propylene and a decrease in the amount of paraffins were observed. According to the obtained results, with an increase in zirconium concentration from 0.4 to 3.2 wt.%, there is an increase in the selectivity for C2-C4 ethylene and propylene from 42.1 to 74.5 wt.%. Paraffins are formed from 0.4 wt.% to 57 wt.% of zirconium. Thus, Mg-Zn-Zr-B/YuKTs is an effective catalyst of methanol to ethylene and propylene, the addition of water to the raw material as a diluent significantly increases the activity of the catalyst and the yield of target products increases and the time of stable operation of the catalyst increases. Also, as a result of studying the textural and physicochemical characteristics of the catalyst by IR-spectroscopy, differential thermal analysis and thermogravimetry methods, it was proved that the treatment of zeolite with zirconium and boron compounds does not lead to the destruction of the zeolite structure.

28.05.2024 Volume 3 Issue 5 View more Download

CATALYTIC SYNTHESIS OF DIMETHYLPHYR FROM IS GAS

Aslanov Sh.Ch., Azimova M.T., Faizullaev N.I., Rahmatov Kh.B.

At present, obtaining dimethyl ether from syngas in one step is an actual issue, and the effect of various factors on the process of direct synthesis of dimethyl ether from syngas in one step was studied in Cu2O·ZnO·ZrO2/YuKTs catalyst. As a result of studies conducted on the effect of various factors on the yield of target products in the process of obtaining dimethyl ether from synthesis gas, it was found that the increase of pressure, temperature, mole ratio of hydrogen to hot gas, and the mole ratio of hydrogen:hot gas leads to an increase in conversion of hot gas. An increase in the volume velocity reduces the conversion of the is gas, because the reaction between the reactants in the gas phase and the methanol catalyst surface does not have time to occur due to the low contact time. It has been proven that the increase in the ratio of gas to hydrogen moles leads to an increase in the yield of dimethyl ether and the conversion of gas. As a result of the research, the following optimal conditions for obtaining dimethyl ether from hydrogen gas in one step were determined: R=1 MPa, T=300℃, hydrogen:gas gas=2, volumetric speed 1000 hour-1. In this case, the conversion of exhaust gas does not decrease for 220 hours. At the same time, the physicochemical and textural characteristics of the Cu2O·ZnO·ZrO2/YuKTs catalyst were studied.

28.05.2024 Volume 3 Issue 5 View more Download

MODERN STATE OF THE PROBLEM HIV/AIDS IN CHILDREN

Nabieva D.D.

Every day, the number of HIV-infected children around the world is increasing, mainly through vertical transmission in utero, during childbirth or in the postnatal period through breastfeeding. Also, one of the most important reasons is the lack of antiretroviral therapy in HIV-infected pregnant women, which can prevent transmission of the infection to the child.