Chemical Raw Materials Research Articles

Optimized Carbon Coupling for Enhanced Ethylene Production via a Unique Single-Atom-Substrate Synergy Mechanism within Photocatalytic Processes.

The utilization of solar-driven technologies for the direct conversion of methanol (CH3OH) into two or multi-carbon compounds through controlled carbon-carbon (C-C) coupling is an appealing yet challenging objective. In this study, we successfully demonstrate the photocatalytic CH3OH coupling to ethylene (C2H4), a valuable chemical raw material, by employing a carbon nitride-based catalyst. Specifically, we modify the layered polymer carbon nitride (PCN) photocatalyst through the incorporation of Au single atoms (Au1/PCN) using a chemical-scissors method. The synergistic effect between the PCN substrate and the Au single atoms reduces the potential barrier associated with C-C coupling, thereby enhancing the efficiency of CH3OH reforming to C2H4. This investigation not only reveals a novel pathway for C2H4 production via CH3OH reforming but also provides fresh insights into the possibilities of C-C coupling.

Engineering a fluorescent probe for the visual and wearable detection of N2H4 in foods, environment samples and biological imaging

Hydrazine (N2H4), as an important chemical raw material widely used in many fields, caused serious harm to human, food and environment. Therefore, a smart fluorescent probe TPC-N2H4 with intramolecular charge transfer (ICT) process was fabricated for colorimetric and fluorescent differentiating of N2H4 in many samples. When TPC-N2H4 met N2H4, blue emission at 451 nm was obviously observed attributed to the interruption of ICT process, resulting in the formation of the hydrazone structure. Additionally, smartphone-assisted colorimetric and fluorescent sensing platforms had been developed for real-time monitoring of N2H4. Importantly, TPC-N2H4 with low toxicity revealed its ability to image N2H4 in HeLa cells, onion and Arabidopsis thaliana. Interestingly, a hydrogel-coated cotton swab sensor was developed with TPC-N2H4 as recognition unit, which showed obvious color and emission changes after N2H4 fumigation with fast response speed. Flexible fluorescent TPC-N2H4-glove was constructed for wearable N2H4 detection and used to monitor N2H4 in food and environment samples. In brief, the TPC-N2H4 probe not only showed great potential in N2H4 detection for environmental and food safety, but also provided a new method for wearable tracking platforms in toxic substance detection.

Pemberdayaan Masyarakat dan Peningkatan Kualitas Pendidikan Serta Optimalisasi Potensi UMKM Lokal melalui Produk dan Pemasaran di Desa Besar II Terjun

Independent Community Service (KKN) in Desa Besar II Terjun by students of the Faculty of Islamic Studies, University of Muhammadiyah North Sumatra aims to improve the quality of education and optimize MSMEs. Through an in-depth survey, the author identified four main problems: the use of chemicals in agriculture, inappropriate educational curriculum, and less than optimal innovation and marketing of MSME products. The implementation method involves face-to-face (on the spot training) with coordination of village officials, as well as the use of chemical raw materials and promotional media to support marketing. The results of the activity show that the author understands the importance of effective communication in building relationships with the community and gaining valuable experience outside the classroom. MSME actors feel helped by the support of students, while the community feels a more lively village atmosphere. This activity is expected to provide significant benefits for the community of Desa Besar II Terjun and be the first step in sustainable empowerment.

Thermodynamic and exergo-economic evaluation of biomass-to-X system combined the chemical looping gasification and proton exchange membrane fuel cell

The resource utilization of biomass is of great significance to the adjustment of energy structure. The syngas produced by biomass gasification can be used for power generation and production of green chemical raw materials. In this paper, a biomass-to-X (BtX) system based on the chemical looping gasification and high temperature proton exchange membrane fuel cell (PEMFC) is proposed to produce methanol, electricity, heating and cooling. The heat produced by the BtX system is harnessed for the regeneration of the carbon capture solution, as well as to drive both the organic Rankine cycle and the double-effect absorption chiller, enabling cascade utilization of the energy. The thermodynamic and exergo-economic models are carried out to evaluate system performance. The relationship between the material, energy and cost flow from biomass to products is analyzed. Finally, the influence of key parameters on system performance is studied. The results show that the energy efficiency of the BtX system is 54.0 % and the exergy efficiency is 35.4 %. The yield rate of methanol with 99.2 wt% purity is 6.48 tons/h. The cost of equipment, propanol and biomass accounts for 34.9 %, 28.9 % and 28.1 % of the total investment cost, respectively, while the cost of the PEMFC stack represents 50.4 % of the equipment costs. The unit exergy cost of the electricity and methanol are 0.068 $/kWh and 0.049 $/kWh, respectively. The methanol, carbon capture and cooling costs are most sensitive to the change in the propanol cost, followed by the biomass cost. For every 0.05 increase in the hydrogen fraction to methanol production, the electricity decreases by 3.1 MW and the methanol yield increases by 0.23 kg/s.

Core-Shell catalyst-mediated hydrodeoxygenation of guaiacol for the preparation of cyclohexanol

Abstract The conversion of lignin-derived phenolic compounds into high-value chemicals through value-added reactions holds significant importance. Cyclohexanol, an essential chemical raw material and organic intermediate, was synthesized in this study from guaiacol, a phenolic compound derived from lignin, through a hydrodeoxygenation reaction. When compared to mechanically mixed and supported catalysts, the use of the HZSM-5@Pd-SiO2 core-shell catalyst resulted in a cyclohexanol yield of 51.1% after a reaction conducted at 493K and 2 MPa H2 for 8h. The core-shell catalyst was characterized using TEM, N2 adsorption-desorption, and NH3-TPD, Py-FTIR revealing its rich acid sites, large specific surface area, and uniform mesopores.

High-performance dicationic ionic liquids based on imidazolium and quaternary ammonium for phenol extraction

Phenolic compounds serve as crucial chemical raw materials abundant in coal tar, so it is of great economic value to extract phenolic compounds from coal tar. Ionic liquids (ILs) are regarded as desirable extractants in this separation field due to considerable advantages over traditional methods. Compared to traditional mono-cationic ILs, dicationic ionic liquids (DILs) exhibit outstanding thermal stability and a wider operating temperature range. Our research focused on developing DILs based on typical imidazolium and quaternary ammonium structures for phenol separation, examining the impact of the methylene chain length between the cations on the extraction efficiency. Hydrogen bonding and π-π interactions between DILs and phenol were also investigated as driving forces in the extraction process. 1-methyl-3-(3-(trimethylammonio)propyl)-1H-imidazol-3-ium bromide ([MIMC3N111][Br]2) with a moderate chain length was selected as the optimal extractant due to its weaker coulomb force inside the DIL, facilitating stronger hydrogen bonding with phenol compared to the other two DILs. Under optimized conditions, [MIMC3N111][Br]2 exhibited the highest extraction efficiency of 96.03 % in model oil (toluene and phenol) with a phenol content of 200 g dm−3 and the DIL to phenol mole ratio was only around 0.3. [MIMC3N111][Br]2 also featured excellent recyclability, maintaining high extraction efficiency through multiple cycles. Importantly, its lower solubility in oil-phenol mixtures compared to mono-cationic ILs significantly reduced contamination of the oil phase. The DILs in this work can exhibit significant potential for separating phenolic compounds with certain advantages.

Highly-efficient separation of pyromellitic acid and trimellitic acid mixtures via forming deep eutectic solvents: Experiment and calculation

Pyromellitic acid (PMA) and trimellitic acid (TMA) are significant chemical raw materials and intermediates. They simultaneously exist in the industry processes of synthesis and are difficult to be separated. In this work, several kinds of biodegradable compounds were chosen as hydrogen bond acceptors (HBAs) to separate PMA and TMA mixtures from acetone solutions via forming deep eutectic solvent (DES). It has been found that all these compounds can separate PMA and TMA mixtures to obtain pure PMA or TMA. However, the interaction between HBAs and PMA or TMA is quite different. Choline chloride cannot extract TMA but can form a DES with PMA in acetone. Hexamethylenetetramine (HA) and L-carnitine (L-car) can form DESs with both PMA and TMA in acetone solution. But when L-car or HA is added, the extraction rate of PMA is larger than that of TMA until the extraction rate of PMA reach 100%, and pure TMA is left in the acetone solution. The selective separation mechanism was explored by infrared spectroscopy combined with quantum chemistry calculation, and the strength and site of the interaction between extractants with PMA and TMA were calculated.

Computational Insight into Transition Metal Atoms Anchored on B2C3P as Single‐Atom Electrocatalysts for Nitrogen Reduction Reaction

AbstractNH3 is not only an important chemical raw material but also a high‐energy storage chemical with zero carbon. Electrocatalytic nitrogen reduction reaction (NRR), which can be driven by clean electric energy under ambient conditions, has become a promising technology for NH3 synthesis due to its environmentally friendly properties. Because of the limitations of low yield and high overpotential, efficient catalysts are urgently needed to solve this problem. In this study, based on density functional theory method and high throughput screening strategy, the NRR was investigated on transition metal single atom anchored to 2D B2C3P surface (TM@B2C3P) as single‐atom catalysts (SACs). The results showed that V@B2C3P and Ti@B2C3P have good catalytic properties, and the limiting potentials were −0.10 and −0.24 V, respectively. Furthermore, the charge density difference and crystal orbital Hamilton population calculations demonstrated that the high catalytic activity can be attributed to the obvious charge transfer between TM@B2C3P and the adsorption intermediates. It is hoped that this work can play a certain role in exploring the application of SACs in NRR.

The influence of CeO2 different morphologies effects on hydrodeoxygenation for guaiacol on Ni/CeO2 catalysts

Catalytic hydrodeoxygenation (HDO) is an effective way to produce high–value products from lignin-derived phenolic compounds. In this work, three different morphologies of Ni/CeO2 catalysts (amorphous, cubic, and rod-shaped) have been prepared through the conventional wet impregnation method. They can be used for the HDO of guaiacol to prepare cyclohexanol, an important chemical raw material. The influence of different morphologies of CeO2 on catalytic activity was explored. The research results indicate that Ni/CeO2–r catalysts with rod-shaped structures exhibit excellent catalytic properties. As a result, a 100 % conversion rate and 96.9 % cyclohexanol yield were achieved on the Ni/CeO2–r catalyst at 240 °C. The catalytic performance of the three catalysts follows this order: Ni/CeO2–r (rod-shaped) > Ni/CeO2–c (cubic) > Ni/CeO2–p (amorphous). The results of Raman and XPS indicate significant differences in the surface oxygen vacancy in catalysts with different morphologies. The Ni/CeO2–r catalyst has the highest oxygen vacancy concentration and defect. In addition, Ni/CeO2–r also has the largest specific surface area (SBET) and the highest nickel dispersion, and forms more Ni0 because of the strong interaction of Ni species and CeO2 support. Therefore, Ni/CeO2–r exhibits the most excellent catalytic performance for the hydrogenation of guaiacol than the other two catalysts. Moreover, the cycling activity test was also investigated over the Ni/CeO2–r catalyst. After five cycles, the conversion rate of guaiacol and the yield of cyclohexanol hardly decrease. This work provides vital ideas for the development of higher-activity, higher-stability, and low-cost catalysts for the conversion of lignin-derived phenolic compounds in the future.

Investigating the effects of industrial transformation and agglomeration on industrial eco-efficiency for green development: Evidence from enterprises in the Yangtze River Economic Belt

Improving industrial eco-efficiency (IEE) is significant for green development, particularly in the areas characterized by intense industrial agglomerations, such as the Yangtze River Economic Belt (YREB). This study analyzes IEE in the middle and lower reaches of the YREB (YREBML) from 2011 to 2020 using the Super SBM-ML model. Based on industrial and commercial enterprise database, this study clarifies the effects of industrial transformation and agglomeration on IEE based on spatial Durbin model. From 2011 to 2020, the IEE in the YREBML exhibited an increased trend, with an average annual increasing rate of 1.48%. The high IEE areas predominantly clustered in eastern coastal cities, while lower IEE regions were mostly located in the central and western areas. Malmquist-Luenberger index decomposition analysis suggests that advanced production technology, improved efficient resource allocation, and optimized industrial structure enhance IEE. The spatial econometric analysis revealed industrial structure rationalization (ISR) and textile industry factory scatter index (FSI) had significant positive effect on IEE, while FSI of chemical raw materials and product manufacturing industry had significant negative effect on IEE. These findings highlight the importance of promoting textile industrial clusters and controlling the quantity and distribution density of chemical industries to improve overall IEE in the YREBML.

A polyhedron-based metal-organic framework with electronegative donor sites for efficient C2H6/C2H4 separation

Ethylene is an important chemical raw material which is widely used in the production of chemical fibers, plastics, rubber, coatings, as well as medicines, and its separation from the gas mixtures of C2H6/C2H4 is of great importance but a challenging task due to their similar physical properties and molecular dimensions. Herein, we report the C2H6 and C2H4 sorption studies on a robust anionic metal-organic framework (MOF) {(NH2Me2)[Co3(μ3OH)(TPT)(TZB)3](H2O)6(DMA)6}n (Co-MOF) formed by connection of Co3(OH) clusters by two N-rich organic ligands 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT) and 4-(1H-Tetrazol-5-yl)benzoic acid (H2TZB). The prepared Co-MOF features a polyhedron stacking network structure composed of trigonal bipyramidal cages and octahedral cage which both contribute to a high C2H6 uptake capacity of 6.48 mmol/g and a decent C2H6/C2H4 selectivity of 1.54 at 298 K and 1 bar. Grand Canonical Monte Carlo (GCMC) simulation results agree well with the experimental tendency, both in the adsorption isotherms and sorption heats, which demonstrated that the suitable pore surfaces with electronegative donor sites generated multiple CH ⋅⋅⋅O/N and CH ⋅⋅⋅π interactions between the framework and C2H6, resulting in a stronger interaction between the MOF skeleton and C2H6 molecule than C2H4 as reflected by the dispersion-corrected density functional theory (DFT) calculation.

Selective Separation of C8 Aromatics by an Interpenetrating Metal-Organic Framework Material.

O-xylene (OX) is an important chemical raw material, but it is often produced in mixtures with other C8 aromatics. Similar physicochemical properties of the C8 isomers make their separation and purification very difficult and energy intensive. There is an unmet need for an adsorbent that would be effective for the separation of OX from the other C8 isomers. This work reports a three-dimensional interpenetrated metal-organic framework, SYUCT-110, that interacts with each of the single-component C8 isomers to form. The selectivity of C8 aromatic hydrocarbons was determined through liquid-phase batch uptake experiments. The results revealed that the selectivity order was OX > PX > MX > ethylbenzene (EB). The selectivity values were found to be 2.63, 1.58, 5.51, 3.71, 1.86, and 3.02 for OX/MX, OX/PX, OX/EB, PX/MX, MX/EB, and PX/EB, respectively. The adsorption capacity of OX was 71 mg/g. Grand Canonical Monte Carlo simulations were used to study the C8 adsorption sites, revealing that π···π interactions are the main reason for the observed adsorption selectivity. The adsorption energy calculation results also verified the selectivity of SYUCT-110 for the synthesis of OX.

All-cellulose colloidal adhesive

At present, adhesives widely used in various industries are mainly synthesized from organic chemical raw materials, and research on replacing traditional chemical raw materials with renewable biomass resources to synthesize adhesives is urgently needed. Adhesives possessing colloidal properties are highly favored due to their distinctive self-assembly capability, and robust reinforcement effects. Here, using cellulose as the sole raw material and following a simple and inexpensive strategy, we prepare a high-performance all-cellulose colloidal adhesive that is resistant to boiling water. We achieve a dry-shear strength of 1.97 MPa with this adhesive and a bonding strength of 0.81 MPa after a cycle of boiling-drying-boiling. The curing mechanism of the adhesive are verified using molecular dynamics simulations. These all-cellulose colloidal adhesives demonstrate great potential to replace traditional adhesives in the near future.

Mechanism analysis and performance comparison of extractive distillation with different extractants for separating methyl tert-butyl ether/methanol mixture

Methyl tert-butyl ether (MTBE) is an important chemical raw material and fuel additive commonly used in the chemical industry and can form minimum boiling azeotrope with methanol (MeOH). In this article, extractive distillation processes with common-extractant (diethylene glycol, DG), counter-extractant (chlorobenzene, CB) and ionic liquid ([MIM][HSO4]) for the separation of MTBE and MeOH binary azeotrope are investigated simultaneously for the first time. Moreover, five quantum chemical calculation methods of σ-profiles, electrostatic potential, interaction energy, Hirshfeld surface and weak interaction are used simultaneously for the first time to reveal the extractive distillation mechanism of different extractants in detail. Finally, three extractive distillation processes (CED-IL, CED-DG, CED-CB) are established and optimized with total annual costs (TAC) and CO2 emissions as objectives. Their performances are comprehensively compared from the aspects of economy, environment, energy, exergy and inherent safety under the optimal conditions. The results demonstrate that, in comparison to the CED-DG process, the CED-IL process reduces TAC by 31.0%, total energy consumption (TEC) and gas emissions by 27.7%, process route index (PRI) by 36.4% and increase thermodynamic efficiency by 46.4%, while the CED-CB process increases TAC by 29.1%, TEC and gas emissions by 23.2%, PRI by 22.1% and reduce thermodynamic efficiency by 11.4%.

CTAC Self-Assembled Alkylated β-Cyclodextrin Loaded onto Functionalized MWCNTs Electrochemical Sensor for NP Detection.

Nonylphenol (NP) is an important fine chemical raw material and intermediate that is widely utilized in industry and may be distributed in aquatic ecosystems. Following its entry into the food and water cycles, it can subsequently enter the human body and potentially harm the human reproductive system. For the purpose of monitoring NP in water, it is thus essential to build a straightforward, affordable, and robust electrochemical sensor. Based on a two-step chemical modification proceeding and an electrostatic self-assembly effect, a double-modified β-cyclodextrin functionalized multiwalled carbon nanotube sensor (HE-β-CD-CTAC/F-MWCNTs) has been successfully constructed. It incorporates the excellent host-guest interaction ability of β-cyclodextrin and the high chemical activity of cetyltrimethylammonium chloride (CTAC), and the carbon nanotubes have an enormous particular surface area and strong electrical conductivity. The electrochemical oxidation reaction of NP with the sensor is controlled by a surface adsorption process of equal numbers of protons and electrons. In accordance with the optimized experimental parameters, the limit of detection (LOD) for the sensor is 0.13 μM, and it responds linearly to NP in the concentration range of 1-200 μM. Meanwhile, the sensor has excellent repeatability, stability, and immunity to interference. For the detection of NP in real water samples, the sensor also showed an excellent recovery rate (92.8%-98.5%) and relative standard deviation (1.16%-3.26%).

A versatile fluorescent probe for the ratiometric detection of hydrazine (N2H4) in water, soil, plant, and food samples

Hydrazine (N2H4) is a crucial chemical raw material extensively utilized in chemical production. However, due to its volatility, water solubility, and high toxicity, both the gaseous form and aqueous solution of N2H4 pose significant environmental risks by causing severe pollution that can adversely impact plants, microorganisms, and human health. Therefore, accurate detection of N2H4 in the environment is imperative for safeguarding public health. In this study, we synthesized a ratiometric fluorescent probe (BCaz-Cy2) based on Carbazole and Hemicyanine groups. This probe exhibits simple synthesis procedure, rapid response time, high sensitivity and selectivity as well as remarkable detection signals. It enables effective detection of N2H4 in various matrices such as water, food, soil and plant samples thereby significantly expanding the scope of applications for N2H4 probes.

Influence of different metal-modified Beta zeolites on the liquid-phase isomerisation of xylene and reaction mechanisms

PX is a very important chemical raw material. There are few studies on the liquid-phase isomerisation of xylene. Here, a series of Beta catalysts with different metal modifications were prepared and tested for many characterisations. The reaction performance of the catalysts was evaluated in the liquid-phase MX isomerisation reaction. The results show that the loading of La, Ce, Mo,Fe and Mg metals decreases the specific surface area and acid content of Beta zeolite. Among them, Mo has a strong interaction with the skeleton Al atoms in Beta. The side reactions of MX isomerisation were inhibited by metal loading, and the selectivity of PX and OX was improved. The effect of Mo content on the liquid-phase isomerisation of MX was further investigated. The selectivity of PX can be improved by appropriate Mo content. This is related to the reaction mechanism of the liquid-phase isomerisation of MX at mainly low temperatures. The acidic site density of B and L acids on the catalyst surface was successfully modulated by Mo loading. At 260 °C, the conversion of MX over Mo/Beta catalyst was about 33 % and the PX yield was 12.83 %. In addition, based on the results of liquid-phase isomerisation of MX, OX and PX, the transformation relationship between the three isomers was investigated.

Process optimization and scale-up of toluene nitration in a microchannel reactor using HNO3-AC2O as nitrating agent

Aromatic nitro compounds are an important class of basic chemical raw materials, while traditional nitration methods may cause safety accidents and environmental pollution due to strong exothermicity and presence of sulfuric acid. In this work, aiming to alleviate these issues, the nitration of toluene was conducted in a microchannel reactor with nitric acid and acetic anhydride. The effect of temperature, molar ratio of nitric acid to toluene, mass fraction of acetic anhydride, and residence time on the conversion and selectivity of reaction were systematically investigated, and response surface methodology was used to optimize the process. A mononitrotoluene yield of 99.21 % can be achieved under optimum condition. Meanwhile, in order to better understand the exothermic behavior, toluene nitration by HNO3-AC2O was investigated in the semi-batch calorimeter. Finally, the optimized process was scaled up and effect of volumetric flow rate was investigated. At the selected maximum volumetric flow rate, the overtemperature of the system was 10.9 °C with a 98.3 % yield of mononitrotoluene. Continuous flow mode had a space-time yield nearly two orders of magnitude greater than semi-batch mode. This work can provide guidance for safe, efficient and green synthesis of mononitrotoluene.

Highly dispersed and stable Schiff base nickel catalyst on multi-walled carbon nanotubes promote ethylene oligomerization

α-Olefins are essential chemical raw materials in the synthesis of emulsifiers, plasticizers, and other value-added chemicals, and ethylene oligomerization is the main method used for preparing α-olefins. However, catalysts employed in ethylene oligomerization have drawbacks such as poor selection of target products, catalyst particle aggregation, and deactivation. To prevent the aggregation of the catalyst and expose a large number of active sites, we propose an anchoring strategy to stabilize and uniformly disperse catalysts on multi-walled carbon nanotubes (MWCNTs). Hybrid catalysts (SCn@MWCNTs) fabricated using the strategy exhibited considerably higher catalytic performance compared with homogeneous Schiff base nickel catalysts (SCn) owing to the combined effects of MWCNTs and active nickel centers. Under optimal catalytic conditions (temperature: 25 °C; Al/Ni molar ratio: 500 (SCn); Al/Ni molar ratio: 700 (SCn@MWCNTs); pressure: 0.7 MPa), the activities of SC1 and SC1@MWCNTs were 6.56 × 104 and 8.25 × 104 g/(mol Ni·h), respectively. In particular, SC1@MWCNTs showed remarkable recyclability and catalytic stability.

Calix[2]azolium[2]benzimidazolone hosts for selective binding of neutral substrates in water

The separation and purification of chemical raw materials, particularly neutral compounds with similar physical and chemical properties, represents an ongoing challenge. In this study, we introduce a class of water-soluble macrocycle compound, calix[2]azolium[2]benzimidazolone (H), comprising two azolium and two benzimidazolone subunits. The heterocycle subunits form a hydrophobic binding pocket that enables H1 to encapsulate a series of neutral guests in water with 1:1 or 2:1 stoichiometry, including aldehydes, ketones, and nitrile compounds. The host-guest complexation in the solid state was further confirmed through X-ray crystallography. Remarkably, H1 was shown to be a nonporous adaptive crystal material to separate valeraldehyde from the mixture of valeraldehyde/2-methylbutanal/pentanol with high selectivity and recyclability in the solid states. This work not only demonstrates that azolium-based macrocycles are promising candidates for the encapsulation of organic molecules but also shows the potential application in separation science.