The interest in Gas-to-Liquid technology (GTL) is growing worldwide because it involves a two-step indirect conversion of natural gas to higher hydrocarbons ranging from Liquefied Petroleum Gas (LPG) to paraffin wax. GTL makes it possible to obtain clean diesel, naphtha, lubes, olefins, and other industrially important organics from natural gas. This article is a brief review discussing the state-of-the-art of GTL, including the basics of syngas manufacturing as a source for Fischer-Tropsch synthesis (FTS), hydrocarbons synthesis (Fischer-Tropsch process), and product upgrading. Each one is analyzed, and the main characteristics of traditional and catalysts technologies are presented. For syngas generation, steam methane reforming, partial oxidation, two-step reforming, and autothermal reforming of methane are discussed. For Fischer–Tropsch, we highlight the role of catalysis and selectivity to high molecular weight hydrocarbons. Also, new reactors technologies, such as microreactors, are presented. The GTL technology still faces several challenges; the biggest is obtaining the right H₂:CO ratio when using a low steam-to-carbon ratio. Despite the great understanding of the carbon formation mechanism, little has been made in developing newer catalysts. Since 60–70% of a GTL plant cost is for syngas production, it needs more attention, particularly for developing the catalytic partial oxidation process (CPO), given that modern CPO processes using a ceramic membrane reactor reduce the plant’s capital cost. Improving the membrane’s mechanical, thermal, and chemical stability can commercialize the process. Catalytic challenges accompanying the FTS need attention to enhance the selectivity to produce high-octane gasoline, lower the production cost, develop new reactor systems, and enhance the selectivity to produce high molecular weight hydrocarbons. Catalytically, more attention should be given to the generation of a convenient catalyst layer and the coating process for a given configuration.

The use of catalytic membranes as microstructured reactors without a separative function has proved effective. High catalytic activity is possible with minimal mass transport resistances if the reactant mixture is pushed to flow through the pores of a membrane that has been impregnated with catalyst. In this study, n-heptane (C₇H₁₆) was hydrocracked and hydro-isomerized within a plug-flow zeolitic catalytic membrane-packed bed reactor. The metallic cobalt (Co) precursor at 3 wt.% was loaded onto support mesoporous materials MCM-48 to synthesize heterogeneous catalysis. The prepared MCM-48 was characterized by utilizing characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR), nitrogen adsorption–desorption isotherms, and the Brunauer–Emmett–Teller (BET) surface area. The structural and textural characteristics of MCM-48 after encapsulation with Co were also investigated. The analyses were performed before and after metal loading. According to the results, the 3 wt.% Co/MCM-48 of metallic catalyst in a fixed bed membrane reactor (MR) appears to have an excellent catalytic activity of ~83% during converting C₇H₁₆ at 400 °C, whereas a maximum selectivity was approximately ~65% at 325 °C. According to our findings, the synthesized catalyst exhibits an acceptable selectivity to isomers with multiple branches, while making low aromatic components. In addition, a good catalytic stability was noticed for this catalyst over the reaction. Use of 3 wt.% Co/MCM-48 catalyst led to the highest isomerization selectivity as well as n-heptane conversion. Therefore, the heterogeneous catalysis MCM-48 is a promising option/ alternative for traditional hydrocracking and hydro-isomerization processes.

MCM-41, a mesoporous silica with a high surface area and hexagonal structure, was synthesized, and commercial nano-silicon dioxide (SiO₂) was used as a solid adsorbed in post-combustion CO₂ capture. The CO₂ adsorption experiments were conducted in a fixed-bed adsorption system using 5–15 vol.% CO₂/N₂ at a flow rate of 100 mL/min at varying temperatures (20–80 °C) and atmospheric pressure. Analyses (X-ray diffraction, nitrogen adsorption-desorption isotherms, Fourier-transform infrared spectroscopy, and transmission electron microscopy (TEM)) revealed that the synthesized MCM-41 has mesoporous characteristics: a high surface area and large pore volumes. The CO₂ adsorption capacity of MCM-41 and commercial nano-SiO₂ increased considerably with increasing CO₂ concentration and temperature, peaking at 60 °C. Below 60 °C, dynamics rather than thermodynamics governed the adsorption. Increasing the temperature from 60 to 80 °C decreased the adsorption capacity, and the reaction became thermodynamically dominant. Additionally, compared with commercial nano-SiO₂, the MCM-41 sorbent demonstrated superior regenerability and thermal stability.

Absorption of CO2 into promoted-NH3 solution utilize a packed column (1.25 m long, 0.05m inside diameter) was examined in the present work. The process performance of four different blended promoters monoethanolamine (MEA)+ piperazine (PZ), piperazine (PZ)+ potassium argininate (ArgK) and monoethanolamine +potassium argininate was compared with unpromoted-NH3 solution by evaluated the absorption rate (φ_(CO_2 )) and overall mass transfer coefficient (K_(G,CO_2.) a_v) over the operating ranges of the studied process variables (1-15Kpa initial partial pressure of CO2, 5-15 Liter/min gas flow rate, 0.25-0.85 Liter/min liquid flow rate). The results exhibit that the absorption behavior and efficiency can be enhanced by rising volumetric liquid flow rate and initial CO2 partial pressure. However, the gas flow rate should be kept at a suitable value on the controlling gas film. Furthermore, it has been observed that the (PZ+ArgK) promoter was the major species that can accelerate the absorption rate and reached almost 66.166% up to123.23% over that of the unpromoted-NH3 solution.

In this study, mesoporous silica nanoparticles (MSNs) with a hexagonal structure and large surface area were synthesized via a sol-gel method. The properties of the synthesized MCM-41 catalyst were characterized using BET, EDX, XRD, and FTIR analyses. The results showed that the MCM-41 had a high surface area of 966 m2/g and large pore volume of about 0.91 cm3/g. Sunflower oil was converted to biodiesel in a batch reactor at different temperatures (40, 50, 60 °C), methanol-to-oil molar ratios (6:1, 9:1, 12:1), catalyst loadings (0.7, 0.9, 1.25 wt%), and reaction times (up to 80 min) using the prepared catalyst under atmospheric pressure. The biodiesel yield was found to reduce when the reaction time exceeded 1 hour despite maintaining the catalyst. The maximum biodiesel yield of 45% was obtained under optimal conditions of a 9:1 methanol-to-oil ratio, 1.25 wt% catalyst loading, 60 °C temperature, and 60 min reaction time. GC-MS analysis characterized the biodiesel composition and properties. The synthesized biodiesel showed improved properties compared to conventional fuels, with linoleic acid methyl ester (C17H34O2, 25.93%) as the main component. The MCM-41 catalyst exhibited remarkable catalytic activity and could be recovered, regenerated, and reused, reducing reaction costs. This makes it a potential alternative to homogeneous catalysts that complicate product separation.