Accelerating the rate of zeolite crystallization enhances synthesis efficiency by either reducing the preparation time or improving zeolite crystallinity for an equivalent preparation time. Herein, the crystallization for a series of MFI zeolites was expedited by partially replacing water in the synthesis gel with oxidized disulfide oil (ODSO), an acid waste byproduct derivative from the E-MEROX process. The water substitution with ODSO reduces the time required to achieve similar to 75% MFI crystallinity down to 2 hat 185 degrees C, from 15 h for an equivalent sol-gel in the absence of ODSO. Similarly, for the same degree of water substitution by ODSO, the MFI crystallinity is increased from similar to 75% to 100% when heating for 15 h. The observed improvements are primarily attributed to ODSO protons, which reduce the gel alkalinity, leading to its faster precipitation. The decreased gel alkalinity also limits crystal dissolution during the growth stage, resulting in a faster growth rate. The enhanced crystallization rate is also attributed to the ODSO counter anion, outperforming other anions tested under similar conditions. Additionally, ODSO yields crystals with hierarchical structures and improved textural properties as a result of following an unclassical crystal growth mechanism promoted by ODSO. These catalysts show similar conversions during the methanol-to-hydrocarbon reaction compared to those prepared in the absence of ODSO. Thus, a feasible valorization of ODSO waste is demonstrated in zeolite synthesis through shortening of the crystallization time, reducing the amount of water required for synthesis, and in producing materials with enhanced textural properties without compromising catalytic performance.

Utilizing industrial wastes as ingredients for zeolite synthesis reduces preparation costs and mitigates the environmental and economic impact of waste disposal. This study demonstrates the successful preparation of various pure zeolites: MFI, faujasite, chabazite, and zeolite beta by substituting 4.5-56 % of deionized water in the synthesis gel with water-soluble oxidized disulfide oil (ODSO), a waste byproduct derivative from the EMerox process. By substituting ODSO, the amount of distilled water required was reduced by up to 56 %. The water economized per Kg of zeolite ranges from 0.3 to 3.4 L. At low-medium substitution, intergrown crystals formed, in 100MFI exhibited up to 14 % higher mesopore volume, 36 % higher mesopore/total pore volume ratio, and 13 % greater surface area compared to the ODSO-free counterpart. At maximum substitution, crystals retained similar morphology to ODSO-free samples, but were significantly larger. Consistent with the crystal size, incorporating ODSO increased crystallization rate, even compared with ODSO-free gels with similar gel alkalinity. For MFI (SiO2/Al2O3 =25), ODSO gave catalysts with superior n-hexane cracking performance to commercial CBV2314 over 500-537 degrees C range. These required 10-37 degrees C lower temperatures to achieve similar conversion rates as the commercial catalyst while maintaining similar selectivity. The catalyst MFI catalyst, prepared with 26 % ODSO substitution, was tested as an additive in fluid catalytic cracking and produced more light olefins than CBV2314 across various catalyst-to-oil ratios. These findings highlight the value of using refinery waste effluent as a solvent component in zeolite synthesis, resulting in materials that outperform those synthesized using only water.

Designing hierarchical zeolites with ordered mesoporosity remains a major synthetic challenge despite their well-established importance in catalysis and separations. In this study, we examine the spatiotemporal dynamics of zeolite dissolution and reorganization to retrace how transient structural changes during zeolite nucleation influence supramolecular self-assembly. For the first time, we demonstrate that subtle differences in the aluminum (Al) spatial proximity and distribution within various zeolite frameworks critically affect their mesostructuring behavior. Notably, beta zeolite comprising distinct polymorphs with marginally different Al environments has shown an anisotropic dissolution pattern, where polymorph B was selectively fragmented, leaving polymorph A unaffected. Through a postsynthetic mesostructuring approach, polymorph B was preferentially reorganized into a gyroidal cubic ordered mesophase, resulting in partially ordered mesoporous beta zeolite. The prepared zeolites exhibit improved catalytic performance in vacuum gas oil hydrocracking, affording high isoparaffin yields and superior naphtha selectivity. These findings provide a direct link between atomic-scale heterogeneity and mesoscale structural evolution in crystals, offering a new strategy for designing advanced catalytic materials.

Zeolites hold importance as catalysts and membranes across numerous industrial processes that produce most of the world's fuels and chemicals. In zeolite catalysis, the rate of molecular diffusion inside the micropore channels defines the catalyst's longevity and selectivity, thereby influencing the catalytic efficiency. Decreasing the diffusion pathlengths of zeolites to the nanoscopic level by fabricating well-organized hierarchically porous architecture can efficiently overcome their intrinsic mass-transfer limitations without losing hydrothermal stability. We report a rational post-synthetic design for synthesizing hierarchically ordered FAU-type zeolites exhibiting 2D-hexagonal ( P6mm ) and 3D-cubic ( Ia d ) mesopore channels. The synthesis involves methodical incision of the parent zeolite into unit-cell level zeolitic fragments by in situ generated base and bulky surfactants. The micellar ensembles formed by these surfactant-zeolite interactions are subsequently reorganized into various ordered mesophases by tuning the micellar curvature with ion-specific interactions (Hofmeister effect). Unlike conventional crystallization, which offers poor control over mesophase formation due to kinetic constraints, crystalline mesostructures can be developed under dilute, mild alkaline conditions by controlled reassembly. The prepared zeolites with nanometric diffusion pathlengths have demonstrated excellent yields of naphtha and middle-distillates in vacuum gas oil hydrocracking with decreased coke deposition.

Surface organometallic chemistry (SOMC) has mainly been devoted to the reaction of organometallics with surfaces comprising highly divided and dehydroxylated oxides. The field has been extended to SOMC on metal nanoparticles. However, to the best of our knowledge, SOMC has not been extended to hierarchical fibrous zeolites, although zeolitic materials are a particular class of oxides. Zeolite catalysis is important in hydrocarbon industrial chemistry. However, having an optimum balance between the activity and selectivity of the zeolitic catalysts remains a major challenge in the field. The main difficultly is the plethora of surface sites, only some of which are catalytically active. Given that the acido-basic properties and porosity of zeolites are especially important to the refining and petrochemical industries, we decided to explore this rather unexplored area. Here, three novel well-defined single-site materials [(Np)3M@ZSM-5, M = Ti, Zr, and Hf] supported on a hierarchical mesoporous H-ZSM-5 material (1) are reported. They are prepared using the concepts and tools of SOMC. They are further converted to their corresponding metal hydride [(H)nM@ZSM-5, M = Ti, Zr, and Hf, (n = 1-2)] materials (5-7) through controlled hydrogenolysis of [(?Si-O-)M(Np)3, M = Ti, Zr, and Hf] materials (2-4) under H2 (1 atm) at 150 degrees C for 16 h. All these surface catalysts are characterized by various spectroscopic techniques including Fourier transform infrared spectroscopy, elemental analysis, solid-state NMR spectroscopy, powder X-ray diffraction, Brunauer-Emmett-Teller surface area measurements, and scanning electron microscopy and high-resolution transmission electron microscopy analyses and are supported by density functional theory calculations. The catalytic activity of these well-defined single-site novel materials will be tested for the catalytic applications in petrochemistry for refinery processes such as hydrocracking of distillates from crude oil or intermediate refinery process streams to useful petroleum value-added products for the society.

The transformation of light naphtha to value-added aromatic compounds is gaining momentum in the petrochemical industry. In this work, a series of metal modified Mo–M/MFI catalysts (M = Fe, Ce, Pt, Ga, and Zn) were synthesized by wet co-impregnation method. Aromatization of light paraffinic naphtha was investigated using modified Mo–M/MFI catalysts at a temperature of 550 °C, atmospheric pressure, and WHSV of 0.81 h−1. Compared to the parent MFI catalyst, the modified bimetallic Mo–Ga/MFI and Mo–Zn/MFI catalysts significantly improved catalytic performance with excellent selectivity (62 wt%) for BTEX (benzene, toluene, ethylbenzene and xylenes) along with 5.4 to 0.6 wt% of C9+ aromatics and ratio of toluene/benzene 0.5 and 0.6, respectively. The higher selectivity to aromatic is attributable to two important factors, the acidity of zeolites and the improved dehydrogenation activity of Mo and the M-modifier. These species effectively transform light naphtha to olefins and then to aromatics by secondary reactions (e.g. isomerization, cracking, dimerization etc.). The modified Mo–Zn/MFI bimetallic catalyst exhibited good stability and selectivity to aromatics with lower ratio of toluene/benzene i.e. ~ 0.6.

We investigated the conversion of light paraffinic naphtha (C5-C6) into BTX (benzene, toluene, and xylenes) aromatics using 1.0 wt % Pt-M/ZSM-5 (modifier M=1 wt% Zn, 2 wt % of Fe, La, Ga) prepared using wet-impregnation method. The effects of Pt and modifier on light naphtha conversion, yield and aromatic selectivity (benzene, toluene, xylene, C9+ aromatics) were studied in fixed-bed flow reactor in atmospheric pressure, at 550 degrees C, and WHSV 1.0 h(-1). Catalytic efficiency of modified Pt or Pt-M ZSM-5 catalysts has been equated to conventional ZSM-5 [Si/Al-2=30] catalyst. While the yield of total aromatics was slightly increased over Pt/ZSM-5 comparison to parent ZSM-5 from 32 wt % to 37 wt %, the value for in situ formed mesoporous Pt-Ga/ZSM-5 was significantly improved reaching 60 wt %. The higher selectivity to aromatics is attributed to the induced mesoporous volumes and dehydrogenation activity of Ga species. These species associated with Pt were effective in the conversion of light naphtha to olefins, which later converted into aromatics by secondary reactions: cracking, isomerization and dimerization. The Pt-Ga/ZSM-5 showed good stability toward the selective production of aromatics at a low toluene/benzene ratio similar to 0.5 due to Pt component.

Large polycyclic aromatic hydrocarbon (PAH) compounds with 7 or more rings, such as coronene, can be problematic in petroleum refining processes, where they build up over time and eventually enhance coke formation. In this work, large PAH molecules were characterized in a recycling stream returning the distillation bottoms of a commercial hydrocracking reactor back into the unit. High-performance liquid chromatography and Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) methods were in good agreement with PAH compounds extracted with DMSO, which provided a selective way to determine PAHs with up to 10 aromatic rings. However, after Soxhlet extraction with pentane, PAH compounds with up to 14 aromatic rings were tentatively identified using FT-ICR MS, extending the naphthalene zigzag pattern. With the characterization method established, solvent extraction, solvent precipitation, and adsorption processes were tested to remove the problematic, large PAH compounds from the recycle stream. For each process, including different parameters, the PAH-rich and cleaned streams were analyzed. Adsorption on clay and adsorption on active carbon were the most effective processes in terms of minimizing the rejected fraction and for removing both types of aromatic compounds: unsubstituted ("hard") and heavily alkylated ("soft") PAHs. Alternatively, solvent precipitation with different nalkanes offered a choice to increase the selectivity for PAH through longer alkane solvents, but showed only a modest removal with PAH remaining in the cleaned streams. Soxhlet extraction was found to he superior in comparison to other solvent extraction processes, yielding the PAH with the highest double bond equivalent values, even though it remains unpractical for real-life hydrocracking operation cleanup. Consequently, the detailed characterization by FT-ICR MS suggests that adsorptive removal of PAH is the most effective and practical cleanup process for the studied hydrocracker recycle stream.

The hydrodearylation process has previously demonstrated the ability to upgrade an aromatic reject stream from an aromatic recovery complex containing heavy alkyl-bridged non-condensed multiaromatics to high-value monoaromatics that include a benzene, toluene, and ethylbenzene/xylene (BTEX) yield of similar to 6 wt %. Herein, a new alternative refining processing option is presented for the same reject stream that not only improves the quality of the gasoline blending component but also significantly increases the BTEX yield. The aromatic reject stream has a limited usage as a gasoline blending component because of its inferior quality. However, by fractionating the reject stream at 180 degrees C, the lighter fraction can be directly sent as a gasoline blending component with a high research octane number without negatively influencing the gasoline specification, and the heavier fraction can be dearylated by subjecting the stream to fluid catalytic cracking. Gas chromatography data show monoaromatic formation at the expense of diaromatic conversion and also present BTEX yields as a function of the processing conditions. Depending on the conditions employed, the BTEX yield in the liquid product can be significantly increased (similar to 37 wt %) compared with the previous configuration. The significant quantities of BTEX formed demonstrate that this new processing configuration-in converting low-value aromatics-provides alternative options to refineries to upgrade the aromatic reject stream.

A new refining process-hydrodearylation-that provides value creation to a refinery aromatic recovery complex is presented. An aromatic reject stream containing heavy alkyl-bridged noncondensed multi-aromatics from an aromatic recovery complex is processed over a zeolite-containing hydrocracking catalyst to recover high-value mono-aromatics including benzene, toluene, and xylenes (BTX). The use of the heavy aromatic bottom stream is limited as a gasoline blending component because of its high density, dark color, and high final boiling point. The hydrodearylation process upgrades the low-value stream containing bridged di-aromatics to significantly enhance high-value mono-aromatic content. Additionally, the process improves the color of the stream from a dark brown/reddish color to a light yellow color together with an observed 3.5% drop in density that improves volume swell. Two-dimensional gas chromatography confirms mono-aromatic formation as a result of di-aromatic conversion with a 15 wt % absolute increase in the mono-aromatic content (>5 wt % BTX) at optimum reaction conditions. Similarly, a 75% reduction in di-aromatics is observed. The mono-aromatics formed may be further processed downstream to add value by yielding additional BTX.

The upgrading of light naphtha (C-5-C-6 stream) to gasoline blending components has been the subject of intensive research at both academic and industrial laboratories. The combination of high volatility and low-octane number has made this stream surplus at many refineries worldwide. This review presents the latest developments in selected catalytic upgrading processes and a brief discussion on the reaction mechanism and reactor models. A majority of the review falls within the development of catalysts for n-hexane isomerization to hydrocarbon isomers with a high octane number. There are three types of isomerization catalysts that include Pt/Al2O3-Cl, Pt/SO4-ZrO2, and Pt/zeolite. Efforts are ongoing to improve the catalyst performance for higher selectivity and catalyst lifetime. Very little work has been published on the conversion of n-pentane mainly as a result of its low activity and the limited options available for its transformation to gasoline blending components. Other approaches discussed in the review include dimerization and oligomerization of C-5-C-6 alkenes and methylative homologation. The review covers literature published during the period of 2000-2018.

The heavy polycyclic aromatic hydrocarbons (HPAHs) cause detrimental effects to hydrocracker operations by deactivating the catalysts and depositing in the downstream of the reactor/ exchangers. Therefore, it is essential to continuously monitor the accumulation of HPAHs in a hydrocracker unit. To accurately measure the concentration of HPAHs, the development of a fast and reliable analytical method is inevitable. In this work, an analytical method based on non-aqueous reversed phase chromatography in combination with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was developed. As a first step, five different types of stationary phases were evaluated for the separation of HPAHs in non-aqueous mode and the best suited phase was further used for the fractionation of HPAHs in a fractionator bottom sample obtained from a refinery hydrocracker unit. The eight major fractions or peaks obtained from the separation were further characterized by UV spectroscopy and FT-ICR MS and the compounds in the fractions were tentatively confirmed as benzoperylene, coronene, methylcoronene, naphthenocoronene, benzocoronene, dibenzoperylene, naphthocoronene and ovalene. The developed liquid chromatography method can be easily adapted in a refinery laboratory for the quantitation of HPAHs in hydrocracking products. The method was further tested to check the interference of sulfur aromatics and/or large alkylated aromatic hydrocarbons on the determination of HPAHs in hydrocracking products.

A three-step oxidative desulfurization (ODS) process comprising of oxidation, liquid–liquid extraction, and adsorption was applied to two compositionally very different commercial diesel samples, namely a straight run middle distillate and a blend of primary and secondary refining streams, to assess the ODS process feasibility. The oxidation of sulfur compounds was achieved using hydrogen peroxide as an oxidant in the presence of tungstic acid catalyst. The diesel feedstocks, intermediate and final products were characterized in detail using standard analytical methods along with state-of-the-art speciation techniques. Under mild conditions (ambient pressure and 80 °C), ODS was found to target sulfur species that are refractory to low-severity hydrodesulfurization (HDS), specifically dibenzothiophenes. The ODS process removed 85.3% and 33.5% of the sulfur compounds in the blend and straight run diesel samples, respectively. A comprehensive material balance for the overall process and each process step was also established, revealing that approximately 80% of the initial diesel could be recovered after desulfurization, when accounting for the removed sulfur compounds. However, any extraction based desulfurization approach has an inherent limit for the achievable overall diesel recovery because of the potentially high mass fraction of organosulfur compounds that is removed in the process. Consequently, ODS should be preceded by an HDS process to target the main bulk of sulfur compounds while the ODS process then removes the remaining HDS refractory compounds. Removal of nitrogen species, which are also undesirable in the final product, was a positive side effect of the studied ODS process.

The reactivity of thiophene, dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT), which are the representatives of the main classes of sulfur compounds that are the constituents of diesel fractions, was studied in the course of their oxidative desulfurization with oxygen on a CuO/ZnO/Al 2 O 3 catalyst modified with boron and molybdenum additives. At T ≥ 375°C, the reactivity increased in the order thiophene < DBT < 4,6-DMDBT. The degree of sulfur removal in the form of SO 2 from hydrocarbon fuel, which was simulated by a solution of 4,6-DMDBT in toluene, was 80%. Under the assumption of a first order reaction with respect to sulfur compound and oxygen, the apparent activation energies of the test processes were calculated. An attempt was made to reveal the role of the adsorption of sulfur compounds in the overall process of oxidative desulfurization with the use of X-ray diffraction analysis, X-ray photoelectron spectroscopy, and differential thermal and thermogravimetric analysis with the massspectrometric monitoring of gas phase composition.

In the hydrocarbons downstream business, it is very beneficial to quickly and reliably determine the physical and/or chemical properties of fuels. In this context, a nondestructive method was applied using midband Fourier transform infrared (FTIR) spectroscopy in association with multivariate partial least squares (PLS) chemometrics to determine the properties of nine groups of middle distillates (diesels) boiling in the range 180-370 degrees C. This method enables identification of one single diesel property at a time or a group of properties (32 properties) simultaneously in the spectral data'between 4000-650 cm(-1); with a minimum number of steps and without any sample preparation. The method was further used for two blends prepared from individual diesel samples. The results showed that using PLS models to process FTIR data is a practical analytical method to predict diesel fuel properties. Statistically, the results obtained showed low standard deviations, a very low root mean square error of cross-validation (RMSECV), low uncertainty values, less than 10 factors, but high correlation coefficient, R-2, and performance index (PI) values.