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TEXTURE INDICATORS FOR CATALYSTS USED FOR ACETYLENE DERIVATIVES, ACETONE AND VINYL ACETATE
OMANOV BEHRUZJON SHUHRAT UGLI
Aassociate professor of the Department of Chemistry, PhD in technical sciences, Navoi State University, Navoi, Uzbekistan
Abstract. Acetone and vinyl acetate take the leading place among the oxygen compounds produced in the world today in petrochemical and basic organic synthesis industries. Today, the annual needfor acetone in the world is 2 million tons, the annual needfor vinyl acetate is 10 million tons, and in our Republic the annual need for acetone is 10-15 thousand tons, and the annual need for vinyl acetate is 40-50 thousand. is a ton. The relative surface area was determined by the BET method. The total volume ofpores was calculated by the amount of adsorbed nitrogen at maximum saturation. Pore size distribution was determined by the BJH (Barrett-Joyner-Halendr) method. Technical conditions of catalysts with high productivity and selectivity of new composition for catalytic hydration and acetylation reactions of acetylene were developed.
Key words: "Wet" suspension, acetone, acetylene, water, HCT, nanocatalyst, acetic acid, vinyl acetate, sol-gel technology, expanded clay
Introduction
The hydration of acetylene (and its derivatives) in Hg (II) salt solutions, discovered by M.G. Kucherov in 1881, has long played a critical role in industrial organic synthesis [1, P. 199-206; 2, P. 4938-4944]. Catalytic hydration of triple bonds is one of the most widespread synthetic methods in chemistry and could regain industrial significance under specific conditions when mercury-free catalysts and diluted acetylene are used [3, P. 597].
Acetone, a volatile liquid with a distinctive odor, is an essential industrial solvent. Due to its low toxicity, it finds widespread application in the production of lacquers, explosives, and pharmaceuticals. It also serves as a precursor in various chemical syntheses [4, P. 22-26; 5, P. 199204]. In laboratory practices, acetone is used as a polar aprotic solvent for preparing cooling mixtures with dry ice and ammonia and for cleaning glassware [6, P. 28-32].
Among oxygen-containing compounds produced in the chemical and basic organic synthesis industries, vinyl esters hold a leading position, with vinyl acetate being particularly significant. Vinyl acetate has been studied since 1909 and was first synthesized and isolated by the German chemist F. Klatte in 1912.
C2H2+2CHbCOOH^ CH3CH(OCOCH3)2 C2H2+CH3COOH ^ CH2=CHOCOCH3
Vinyl acetate is one of the most important monomers, with its production rapidly growing worldwide. It is a key monomer in the plastics industry, used to synthesize polyvinyl acetate, polyvinyl acetal, and polyvinyl alcohol. Additionally, polyvinyl acetate and polyvinyl alcohol are critical in medicine, agriculture, synthetic rubber, artificial fibers, the creation of biologically active substances, and other materials with unique properties [7].
Currently, the global annual demand for acetone is approximately 2 million tons, and for vinyl acetate, it is 10 million tons. In Uzbekistan, the annual demand for acetone is estimated at 10,00015,000 tons, while the annual demand for vinyl acetate is around 40,000-50,000 tons. Thus, conducting research to develop and improve technologies for producing acetone and vinyl acetate using local catalysts is a pressing need.
Analysis and Results
The textural characteristics of the samples were obtained using an ASAP 2010 M device via low-temperature adsorption of liquid nitrogen at 77.35 K. Before analysis, the samples were dried at 120°C for 4 hours and calcined at 550°C for 6 hours.
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The textural characteristics of the catalyst include bulk, relative, and true densities; porosity; specific surface area; total pore volume; and pore size distribution.
The bulk density was determined by weighing 100 mL of catalyst, and it was calculated using the following formula:
Pcarving
m
V
In this context: V represents the sample volume, which is equal to the volume of the catalyst material; m is the mass of the catalyst.
The total volume is calculated as follows:
V=Vcat+Vpore+Vfree
where Vcat is the volume of the catalyst material, and Vpore is the volume of the catalyst's pores. The relative density is calculated using the formula:
m
Prelative
The true density is determined as:
Vmt- + Vpore
cat
m
Ptrue =
К
cat
Here, Vcat refers to the volume of the solid phase of the catalyst, excluding the pore and inter-particle voids.
The relative and true densities were measured using a pycnometric method. Various liquids such as water, mercury, hydrocarbons, or alcohols were used depending on the sample's properties.
The ZnO:Fe2O3:Cr2O3:MnO2:V2Os/HSZ composite nanoparticles were synthesized based on a core-shell structure design. The precise methodology involves layering and stabilizing the components to achieve the desired functional properties.
Mn(NQ3b-6HzO I I VOtNOsb I
Formation of colloidal solutions
5
NaOH + H20
Fe(N03)3-6H20, Cr(N03)3-9H20
Magnetic stirring
-4
Zn(NOJj 6H20
Gel Formation: ZnOFeiOj-CrjOrMnOj
■v2os !
N<)OI I i I I .O
Ж
Gel Separation via Centrifugation
-w ^^
Vacuum Drying: 6 hours, 500°C
Ready-made product Fez03 + ViOs
Cr¡.03 ■Cj ZnO + M пОг
Scheme 1. Synthesis Scheme of ZnO:Fe2O3:Cr2O3:MnO2:V2Os/HSZ Nanoparticles
Subsequently, we studied the effect of the mass ratios of the active components of the catalyst on the activity in the catalytic hydration reaction of acetylene. The results obtained are presented in Table 1.
Table 1. Textural Characteristics of the ZnO^O^CnO^MnO^Os/HSZ-Based
Catalyst
№ Form of Density, Ssol m2/g Total volume of ZnO:Fe2O3:Cr2O3:MnO2amo
granule g/cm3 the pore, cm3/g unts, mass in %
1. cylindrical 0,98 51 0,310 30:30:30:3
2. cylindrical 0,94 63 0,341 30:0:30:0
3. cylindrical 0,88 46 0,253 0:30:30:5
4. cylindrical 0,76 107 0,362 15:5:15:1
5. cylindrical 0,72 173 0,409 5:15:15:3
6. cylindrical 0,86 57 0,337 15:15:5:4
7. cylindrical 0,79 62 0,313 5:5:0:3
8. cylindrical 0,87 59 0,329 5:5:5:2
9. cylindrical 0,88 70 0,318 5:5: 5:3
10. cylindrical 0,92 51 0,310 5:5:5:1
11. cylindrical 0,85 59 0,271 5:5:5:0
In the catalytic acetylation reaction of acetylene, the productivity of the catalyst has the highest value when the ratio of the mass ratio of the active components of the catalyst to the catalyst activity
is 5:5:5:3 (in mass percent).
Cd(CH3COOb + НгО
Ceramsite
Zr0(N03b
Citric acid
Mixing in a magnetic stirrer
Zn(CH,COO)3HjO
Formation of colloidal sol utions
NHj H20
3E
Formation of ZnOCdOZrOz/ceramsite gel
Gel Separation via
Centrifugation
-
Air drying for 6 12 hours
Ж
Heating in a furnace at +ЮСГС to +500°C
ZrOj
——
-к Cdo
V ZnO
ceramsite
Scheme 2. Synthesis scheme of ZnO-CdO-ZrO2/keramzite nanoparticle
After that, we studied the effect of the mass ratio of the catalyst active components on the catalyst activity in the catalytic acetylation reaction of acetylene. The obtained results are presented in Table 2.
№ Form of Density, Ssol m2/g Total volume of the ZnO:CdO:ZrO2 amounts,
granule g/cm3 pore, cm3/g mass in %
1 cylindrical 0,98 51 0,310 45:15:1.5
2 cylindrical 0,94 63 0,341 45:30:1.5
3 cylindrical 0,88 46 0,253 30:45:1.5
4 cylindrical 0,85 51 0,250 15:15:1.5
5 cylindrical 0,76 107 0,362 15:45:1.5
6 cylindrical 0,72 173 0,409 30:15:1.5
7 cylindrical 0,86 57 0,337 15:30:1.5
In the catalytic acetylation reaction of acetylene, the productivity of the catalyst has the highest value when the ratio of the mass ratio of the active components of the catalyst to the catalyst activity is 15:15:1.5 (in mass percent).
Sample S,% P, g/cm3 P, m2/g P, g/cm3 £ a
ZnO-Fe2O3^Cr2O3^MnO2-V2O5/HSZ 3,58 0,881 1,51 2,82 0,412 0,468 0,32
ZnO-CdO-ZrO2/keramzite - 0,873 1,41 2,90 0,363 0,523 0,37
a - particle porosity and Vz - total pore volume Table 4. Key Characteristics of Catalyst Sample Textures
Sample Coke, % Sbet, mg/l St, m2/g Vs(P/P0=0,99), cm3/g V, cm3/g D, nm
ZnO-Fe2O3 • &2O3 -MnO2 •V2O5/HSZ 3,58 1725 158 0,380 0,0057 9,4
ZnO-CdO-ZrO2/keramzite - 2117 190 0,415 0,0072 8,7
Conclusion
Using "wet" and suspension-based techniques along with "sol-gel" technology, nanocatalysts with high thermal stability, activity, selectivity, and productivity were developed from local raw materials for the catalytic hydration of acetylene and acetylation reactions. These include ZnO-Fe2O3^Cr2O3^MnO2^V2O5/HSZ for catalytic hydration of acetylene and ZnO-CdO^ZrO2/keramzite for acetylation. Technical specifications for new, highly efficient, and selective catalysts tailored to acetylene hydration and acetylation reactions were also developed.
REFERENCES
1. Akolekar D. В., Bhargava S. К. (2000) Adsorption of NO and CO on silver-exchanged microporous materials // J. Mol. Catal. A: Chem. 157(1-2). P. 199-206.
2. Antony S., Bayse С. А. (2009) Theoretical Studies of Models of the Active Site of the Tungstoenzyme Acetylene Hydratase // Organometallics. 28(17). P. 4938-4944.
3. Astruc D. (2007) Organometallic Chemistry and Catalysis. Berlin: Springer-Verlag. 597 p.
4. Мусулмонов Н.Х., Икрамов А., Кадиров Х.И. Роль ацетатов при синтезе винилацетата // Узбекский химический журнал. -Ташкент. 2010. №1. С.22-26.
5. Omanov B.Sh. // Compact technology of acetone production// Science and Education in Karakalpakstan ISSN 2181-9203. №1/1 (38) 2024. 199-204 betlar
6. Omanov B.Sh. Chemical reactor modeling in acetone production process using aspen plus software// Universum: технические науки. 3(120) Март 2024. Часть 9. P. 28-32.
7. Bekhruzjon Omanov, Normurot Fayzullaev, Mukhabbat Khatamova, Almagul Xalibekova, Madina Avezova//Optimizing Vinyl Acetate Production Process and Selecting of Appropriate Reactor Type//AIP Conference Proceedings 2789, 020008 (2023) https://doi.org/10.1063/5.0145637
