Butyl Research Articles

Advanced Process Control Strategies for Efficient Methanol Production from Natural Gas

Natural gas-to-methanol plants are receiving renewed interest with the significant increase in shale gas availability. Methanol serves as a crucial raw material for producing various industrial and consumer goods as well as key platform chemicals, including acetic acid, methyl tertiary butyl ether, dimethyl ether, and methylamine. In this research, a dynamic model is developed for Natgasoline’s methanol manufacturing plant. A hierarchical control system comprising Dynamic Matrix Control (DMC) and a basic regulatory control loop is constructed using this dynamic model to minimize methanol losses and utility costs under various process upsets. A subspace identification methodology is used to develop rigorous DMCplus controller models. The simulation results in the ASPEN manufacturing software platform show that the DMCplus controller developed in this study can reduce methanol losses by 96% and utility requirements by 40%. The controller is robust to feed flow variations of ±10%. Furthermore, disturbances due to the variation in hydrogen content in the syngas are also successfully rejected by the controller. This hierarchical multivariable control system performs significantly better than the traditional regulatory PID control strategy in optimizing the methanol process under process constraints.

Investigation photophysical, photochemical and aggregation properties of A3B type Zn(II) and In(III) phthalocyanines containing tert-butyl and benzodioxane groups

Investigation photophysical, photochemical and aggregation properties of A3B type Zn(II) and In(III) phthalocyanines containing tert-butyl and benzodioxane groups

Photo- and electroluminescent properties of V-shaped fused-biscoumarins containing tert-butyl group modified imidazole/carbazole groups

Photo- and electroluminescent properties of V-shaped fused-biscoumarins containing tert-butyl group modified imidazole/carbazole groups

Cationic‐Hydrophilic Di‐Block Copolymers: Surface‐Shielded Vectors for Gene Delivery

ABSTRACTTo tackle the main challenges in gene therapy, synthetic polycationic vectors are developed for nucleic acid (NA) delivery. In this work, vectors based on di‐block copolymers consisting of a methacrylate‐type cationic block and an electroneutral hydrophilic block are designed and synthesized to condense NA into compact particles shielded with a bioinert hydrophilic polymer layer. The results confirm that the cationic vector blocks, containing permanently charged trimethylammonium (TMA) or tributylphosphonium (TBP) groups and 0–20 mol% hydrophobic butyl groups, are able to efficiently complex DNA to form 100 to 200 nm spheroids, while the hydrophilic blocks based on 2‐methacryloyloxyethylphosphorylcholine or N‐(2‐hydroxypropyl) methacrylamide coat the nanoparticle surfaces with an electroneutral polymer layer. Additionally, pH‐responsive hydrazone bonds are incorporated between the TMA and TBP groups and the main polymer backbone of the polycationic block to ensure hydrolysis of the hydrazone bond. Theoretically, this should be accompanied by DNA release from the complex in a mildly acidic environment inside the cells while maintaining its stability under neutral blood conditions. In summary, this model study provides insight into the process of complexation/decomplexation of NA by pH‐responsive di‐block polycationic vectors. The results may contribute to the development of safe and efficient delivery systems for gene therapy applications.

Optimizing Therapeutics for Intratumoral Cancer Treatments: Antiproliferative Vanadium Complexes in Glioblastoma

Glioblastoma, an aggressive cancer, is difficult to treat due to its location, late detection, drug resistance, and poor absorption of chemotherapeutics. Intratumoral drug administration offers a promising potential treatment alternative with localized delivery and minimal systemic toxicity. Vanadium(V) coordination complexes, incorporating Schiff base and catecholate ligands, have shown effects as antiproliferative agents with tunable efficacy and reactivity, stability, steric bulk, hydrophobicity, uptake, and toxicity optimized for the intratumoral administration vehicle. A new series of oxovanadium(V) Schiff base–catecholate complexes were synthesized and characterized using nuclear magnetic resonance (NMR), UV-Vis, and infrared spectroscopy and mass spectrometry. Stability under physiological conditions was assessed via UV-Vis spectroscopy, and the antiproliferative activity was evaluated in T98G glioblastoma and SVG p12 normal glial cells using viability assays. The newly synthesized [VO(3-tBuHSHED)(TIPCAT)] complex was more stable (t1/2 ~ 4.5 h) and had strong antiproliferative activity (IC50 ~ 1.5 µM), comparing favorably with the current lead compound, [VO(HSHED)(DTB)]. The structural modifications enhanced stability, hydrophobicity, and steric bulk through substitution with iso-propyl and tert-butyl groups. The improved properties were attributed to steric hindrance associated with the new Schiff base and catecholato ligands, as well as the formation of non-toxic byproducts upon degradation. The [VO(3-tBuHSHED)(TIPCAT)] complex emerges as a promising candidate for glioblastoma therapy by demonstrating enhanced stability and a greater selectivity, which highlights the role of strategic ligand design in developing localized therapies for the treatment of resistant cancers. In reporting the new class of compounds effective against T98G glioblastoma cells, we describe the generally desirable properties that potential drugs being developed for intratumoral administration should have.

Unveiling emissive H-aggregates of benzocoronenediimide, their photophysics and ultrafast exciton dynamics.

H- and J-aggregates of many molecules can be considered ordered mesoscopic structures that behave like a single entity. This is due to coherent electronic coupling between electronic excitations of aggregated molecules, resulting in distinct electronic properties compared to the monomer. H-aggregates are generally non-emissive and, due to this property, they are considered unfit for optoelectronics applications, but they have found applications in organic light-emitting transistors. Herein, we designed t-butyl-substituted benzocoronenediimide (t-But-BCDI) forming rare emissive H-aggregates. The tertiary butyl groups are placed to inhibit the formation of strong aggregates. Photophysical studies showed that t-But-BCDI forms H-aggregates in a concentrated solution in a THF/CHCl3 mixture. A blue shift in absorption along with a decrease in the A0-0/A0-1 ratio and red-shifted weaker emission are observed for the aggregate compared to the monomer. Ultrafast transient absorption studies revealed biphasic relaxation with lifetimes of 150 (±10) fs and 13 (±2) ps, which are attributed to a higher-to-lower state transition and vibrational cooling, respectively. The transient spectral signature suggests the Frenkel-type (localized to a monomer) character of the exciton. Faster evolution at the tens of picosecond timescale suggests relaxation of the exciton state within the H-type exciton band. An extraordinarily long emission lifetime from the H-aggregated state is observed.

Effect of Activated GGBS on Remediation of a Clay Soil Contaminated With MTBE

ABSTRACTThis research investigates the efficacy of magnesium oxide (MgO) activated ground granulated blast furnace slag (GGBS) in remediating a clay soil contaminated with methyl tertiary butyl ether (MTBE) through a program of laboratory tests. The contamination was simulated by artificially introducing 2.25 mg MTBE per kg of soil in the laboratory. The GGBS activation process involved mixing GGBS and MgO in a ratio of 3:1. The resulting mixture was then added to both natural and contaminated soil samples at percentages of 0.25%, 0.5%, and 1.0%. The results demonstrated that the addition of the binder improved the strength of both natural and contaminated soil samples, with the magnitude of strength enhancement dependent on the percentage of the additive and the curing time. The results of leaching tests also revealed that the effectiveness of remediation of contaminated soil varied based on the percentage of the binder used and the duration of curing. Furthermore, scanning electron microscopy analysis indicated that the changes in soil properties and the effectiveness of remediation were attributed to chemical interaction between the soil minerals, the pollutant, and the binder. The results showed that the selected additive is suitable for the remediation of the contaminated soil.

Dopant-free tert-butyl Zn(ii) phthalocyanines: the impact of substitution on their photophysical properties and their role in perovskite solar cells

We synthesized molecular hole-transporting materials featuring a zinc phthalocyanine (ZnPc) central core and modulated the non-peripheral position with different numbers of tert-butyl groups.

Toluene and methyl tert butyl ether bioaccessibility in soils: The influence of their coexistence

Toluene and methyl tert butyl ether bioaccessibility in soils: The influence of their coexistence

Effect of di tert butyl peroxide on performance, emissions and vibration characteristics of diesel fuel with HHO gas as secondary fuel

Effect of di tert butyl peroxide on performance, emissions and vibration characteristics of diesel fuel with HHO gas as secondary fuel

Analysis of Pz-1, a promising therapeutic for organophosphorus poisoning from rodent plasma by liquid chromatography-tandem mass spectrometry.

Organophosphorus (OP) pesticides (e.g., parathion) and nerve agents (e.g., soman) can produce acute and long-term neurological problems. Exposure to OP chemicals is responsible for an estimated 200,000 deaths annually. Pz-1 (N-(5-(tert butyl)isoxazol-3-yl)-2-(4-(5-(1-methyl-1H-pyrazol-4-yl)-1H-benzo[d]imidazol-1-yl)phenyl)acetamide) is a muscle specific kinase (MuSK) inhibitor which has shown potential as a treatment for OP chemical exposure and as a tyrosine kinase inhibitor to impede the growth of cancer cells. While development of this treatment requires the availability of a validated analytical method, no method currently exists for analysis of Pz-1 from biological samples. In this study, an analytical method was developed for Pz-1 from rat (and mouse) plasma. Plasma was prepared by precipitating plasma proteins, isolating the supernatant, evaporating to dryness and reconstituting in 1:1 MeOH:water. Prepared samples were analyzed by reversed-phase liquid chromatography tandem mass-spectrometry (LC-MS/MS). The method produced excellent sensitivity, with a limit of detection of 1 nM (455 ng/L). The calibration range was 3-100 nM and the calibration curve produced excellent linear behavior (R2 ≥ 0.99 and PRA ≥ 91 %). The method also showed good accuracy and precision. The validated method was used to detect Pz-1 in mouse plasma following intraperitoneal (IP) treatment with 5 mg/kg Pz-1. In summary, this method shows promise as a simple and sensitive method to analyze Pz-1 in rat plasma to facilitate its continued development as a treatment for OP toxicity.

Synthesis, Luminescence, and Electrochemistry of Tris-Chelate Platinum(IV) Complexes with Cyclometalated N-Heterocyclic Carbene Ligands and Aromatic Diimines.

Dicationic, C2-symmetrical, tris-chelate Pt(IV) complexes of general formula [Pt(trz)2(N∧N)](OTf)2, bearing two cyclometalated 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-ylidene (trz) ligands and one aromatic diimine [N∧N = 2,2'-bipyridine (bpy, 2), 4,4'-di-tert-butyl-2,2'-bipyridine (dbbpy, 3), 4,4'-dimethoxi-2,2'-bipyridine (dMeO-bpy, 4), 1,10-phenanthroline (phen, 5), 4,7-diphenyl-1,10-phenanthroline (bphen, 6), dipyrido[3,2-a:2',3'-c]phenazine (dppz, 7), or 2,3-diphenylpyrazino[2,3-f][1,10]phenanthroline (dpprzphen, 8)] are obtained through chloride abstraction from [PtCl2(trz)2] (1) using AgOTf in the presence of the corresponding diimine. Complexes 2-4 show long-lived phosphorescence from 3LC excited states involving the diimine ligand, with quantum yields that reach 0.18 in solution and 0.58 in the solid matrix at room temperature for 3. Derivatives with more extended aromatic systems show dual phosphorescent/fluorescent emissions (5, 6) or mainly fluorescence (7, 8) in solution. Comparisons with similar complexes bearing cyclometalated 2-arylpyridines instead of aryl-N-heterocyclic carbenes indicate that the {Pt(trz)2} subunit is crucial to enable efficient emissions from diimine-centered excited states. It is also shown that the introduction of protective bulky substituents on the diimine, such as the tert-butyl groups in 3, is a key strategy to reach higher emission efficiencies. The new compounds represent rare examples of luminescent Pt(IV) complexes that show quasi-reversible one-electron reductions, indicating an unusually high redox stability.

Origins of Narrowband Emission in Nitrogen/Carbonyl Multiresonance Thermally Activated Delayed Fluorescence Emitters: Steric Locks and Vibrational Coupling Effects.

The incorporation of tert-butyl groups and spiro-functionalization into C═O/N-embedded multiresonance thermally activated delayed fluorescence (MR-TADF) systems has yielded materials with superior narrowband emission and excellent color purity. To elucidate the mechanisms underlying the enhanced properties, we present a theoretical study of a series of fused nitrogen/carbonyl derivatives with narrower emission profiles. The key steric factors that contribute to narrowband emission were identified through energy decomposition analysis, induced by structural relaxation in states S0 and S1. Additionally, we achieved potential narrower-band and deep-blue emission by targeting the suppression of vibrational coupling effects. This work provides compelling evidence that a 1-tert-butyl substitution, acting as an end lock, offers minimal reorganization energy and optimal structural stability when combined with a fused lock. Furthermore, new compounds such as 1tBuCZQ and 1tBuDQAO have been identified as promising MR-TADF emitters, delivering ultranarrowband emission as high-quality organic light-emitting diodes.

Controlled Helical Organization in Supramolecular Polymers of Pseudo-Macrocyclic Tetrakisporphyrins.

Tetrakisporphyrin monomers with amino acid side chains at each end form intramolecular antiparallel hydrogen-bonds to adopt chirally twisted pseudo-macrocyclic structures that result in right-handed and left-handed (P)- and (M)-conformations. The pseudo-macrocyclic tetrakisporphyrin monomers self-assembled to form supramolecular helical pseudo-polycatenane polymers via head-to-head complementary dimerization of the bisporphyrin cleft units in an isodesmic manner. The formation of one-handed supramolecular helical pseudo-polycatenane polymers was confirmed by circular dichroism (CD) spectroscopy. The methyl and iso-propyl groups at the stereogenic center greatly enhanced the induced circular dichroism in the Soret bands of the supramolecular helical pseudo-polycatenane polymers. The induced CDs were reduced upon the introduction of large iso-butyl and tert-butyl groups. Atomic force microscopy revealed well-grown and long supramolecular helical pseudo-polycatenane polymer chains with chain lengths in the range of 361 to 13.6 nm. The right-handed helical chains were established by the self-assembly of the right-handed (P)-conformation of the pseudo-macrocyclic monomer.

CF3-Cyclobutanes: Synthesis, Properties, and Evaluation as a Unique tert-Butyl Group Analogue.

Isosteric replacement of functional groups is an emerging strategy for optimizing bioactive molecules in drug discovery. tert-Butyl group is a particularly important moiety, yet its isosteric replacement with 1-trifluoromethyl-cyclobutyl group has been rather neglected. To enable the advance of this molecular fragment in drug discovery programs, we report the synthesis of over 30 small-molecule building blocks featuring the trifluoromethyl-cyclobutyl fragment, achieved by reacting sulfur tetrafluoride with cyclobutylcarboxylic acids on a gram-to-multigram scale. Furthermore, we characterized the structural properties of this group through X-ray analysis, studied its effect on acid-base transitions, and evaluated its Hammett parameters. Finally, we evaluated the replacement of tert-butyl with 1-trifluoromethyl-cyclobutyl in several bioactive compounds that represent commercial drugs and agrochemicals. Our findings indicate that while the trifluoromethyl-cyclobutyl group exhibited slightly larger steric size and moderately increased lipophilicity, it preserved the original mode of bioactivity in the examined cases and, in some cases, enhanced resistance to metabolic clearance.

SERCA Modulators Reveal Distinct Signaling and Functional Roles of T Lymphocyte Ca2+ Stores.

The allosteric SERCA (Sarcoplasmic/Endoplasmic Reticulum Ca2+-ATPase) activator CDN1163 has been recently added to the group of pharmacological tools for probing SERCA function. We chose to investigate the effects of the compound on T lymphocyte Ca2+ stores, using the well-described Jurkat T lymphocyte as a reliable cell system for Ca2+ signaling pathways. Our study identified the lowest concentrations of the SERCA inhibitors thapsigargin (TG) and 2,5-di-(tert butyl)-1,4-benzohydroquinone (tBHQ) capable of releasing Ca2+, permitting the differentiation of the TG-sensitive SERCA 2b Ca2+ store from the tBHQ-sensitive SERCA 3 Ca2+ store. We proceeded to test the effects of CDN1163 on Ca2+ stores, examining specific actions on the SERCA 2b and SERCA 3 Ca2+ pools using our low-dose SERCA blocker regimen. In contrast to previous work, we find CDN1163 exerts complex time-sensitive and SERCA isoform-specific actions on Ca2+ stores. Surprisingly, short-term exposure (0-30 min) to CDN1163 perturbs T cell Ca2+ stores by suppressing Ca2+ uptake with diminished Ca2+ release from the SERCA 2b-controlled store. Concomitantly, we find evidence for a SERCA-activating effect of CDN1163 on the SERCA-3 regulated store, given the observation of increased Ca2+ release inducible by low-dose tBHQ. Intriguingly, longer-term (>12 h) CDN1163 exposure reversed this pattern, with increased Ca2+ release from SERCA 2b-regulated pools yet decreased Ca2+ release responses from the tBHQ-sensitive SERCA 3 pool. Indeed, this remodeling of SERCA 2b Ca2+ stores with longer-term CDN1163 exposure also translated into the compound's ability to protect Jurkat T lymphocytes from TG but not tBHQ-induced growth suppression.

Microwave assisted synthesis of ErxYbyCa1-x-yMoO4 nano-phosphor for efficient temperature sensing and catalytic applications

Here, Er/Yb Co-doped CaMoO4 materials (ErxYbyCa1−x−yMoO4 NPs where x = 0, 0.01 and y = 0, 0.05, 0.10, 0.15, 0.20) were prepared by microwave-assisted method and its pure-tetragonal structure were confirmed by X-ray diffraction spectra (XRD), Rietveld-refinement and Raman-vibrational spectra. The transmission-electron microscopy (TEM) study indicates the formation of nearly spherical shaped nanomaterial with average size of ~ 15 nm. Additionally, absorption and emission properties were studied by UV–Visible–NIR and photoluminescence (PL) spectrometer. The UV–Visible–NIR spectra attribute absorption of Er3+ ion in visible region (380–700 nm) and absorption of Yb3+ ion in near-infrared region (700–1400 nm). Moreover, PL up-conversion spectra of the sample recorded under excitation wavelength 980 nm. The PL peaks were observed at 530, 544–552, and 656–670 nm. Prominent PL-intensity was observed for Er0.01Yb0.15Ca0.84MoO4 phosphor. Temperature dependent PL study reveals that present phosphor is robust phosphor for temperature sensor. In addition, Er3+/Yb3+ doped CaMoO4 nanomaterials exhibited excellent activity and selectivity in the aerial oxidation of benzoin over benzyl under oxidant-free reaction conditions. The synergistic effect Er3+/Yb3+ co-doing in CaMoO4 matrix was observed, where only CaMoO4 material found to be inactive towards above oxidation reaction. Moreover, the oxidation of primary benzyl-alcohols was furnished in presence of tertiary butyl hydroperoxideas oxidant.

Stereo-Hindrance Induced Conformal Self-Assembled Monolayer for High Efficiency Inverted Perovskite Solar Cells.

Self-assembled monolayers (SAMs) are employed as hole-selective contacts in inverted perovskite solar cells (PSCs) and have achieved record power conversion efficiency (PCE) over 26%. However, the tendency of extensively employed SAM [2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid to aggregate leads to its uneven coverage to the transparent conducting oxide substrate, which subsequently compromises the photovoltaic performance. Herein, a novel tert-butyl functionalized phosphonic acid carbazole SAM is developed, i.e., (4-(3,6-di-tert-butyl-9H-carbazol-9-yl)butyl)phosphonic acid (tBu-4PACz), and introduced to a mixed SAM system as the hole-extraction layer in inverted PSCs. The stereo-hindrance of the bulky tert-butyl group prevents undesired aggregation and leads to better conformality, which facilitates more efficient hole-extraction and suppresses interfacial recombination losses. The tBu-4PACz SAM-based inverted PSC has achieved record level PCE of 26.25% (26.21%, certificated) with outstanding fill factors over 86%. Moreover, the mixed SAM based inverted PSC devices maintained over 94.7% of their initial efficiency after 500h continuous maximum power-point tracking under simulation 1-sun irradiation.

Study of Hydrolysis Kinetics and Synthesis of Single Isomer of Phosphoramidate ProTide-Acyclovir.

Acyclovir (ACV) is a vital treatment for herpes simplex (HSV) and varicella-zoster virus (VZV) infections that inhibit viral DNA polymerase. Phosphoramidate ProTides-ACV, a promising technology, circumvents the reliance on thymidine kinase (TK) for activation. Twelve novel single isomers of phosphoramidate ProTide-ACV were synthesized. Successful isomer separation was achieved, emphasizing the importance of single isomers in medical advancements. The enzymatic hydrolysis kinetics of the synthesized compounds were investigated by using carboxypeptidase Y (CPY). The results revealed a faster conversion for the isomer Rp- than for the Sp-diastereomer. Hydrolysis experiments confirmed steric hindrance effects, particularly with the tert-butyl and isopropyl groups. Molecular modeling elucidated the mechanisms of hydrolysis, supporting the results of the experiments. This research sheds light on the potential of phosphoramidate ProTides-ACV, bridging the gap in understanding their biological and metabolic properties, while supporting future investigations into anti-HSV activity. Preliminary screening revealed that three of the four single isomers demonstrated superior antiviral efficacy against wild-type HSV-1 compared to acyclovir, with isomer 24a ultimately reducing the viral yield at 200 μM. These findings emphasize the importance of isolating racemic ACV-ProTides as pure single isomers for future drug development.

Measurement of Acrylamido Tertiary Butyl Sulfonate Polymer Retention on Limestone by Three Methods Under Varying Temperature and Oil Presence

Summary Polymer retention poses a significant challenge in polymer flooding applications, emphasizing the importance of accurately determining retention levels for successful project design. In carbonate reservoirs of the Middle East, where temperatures exceed 90°C, conducting adsorption tests under similar temperature conditions becomes crucial for the precise determination of adsorption values. The choice of analytical method potentially impacts the accuracy of retention measurements from effluent analysis. This study investigates the effect of temperature on the performance of a polymer, specifically its rheological behavior and retention. Rheological and polymer flooding experiments were carried out using an acrylamido tertiary butyl sulfonate (ATBS)-based polymer in formation water (167,114 ppm) at different temperatures (25°C, 60°C, and 90°C) with required oxygen control measures. Dynamic polymer retention was conducted in both the absence of oil (single-phase tests) and the presence of oil (two-phase tests). In addition, different analytical techniques were evaluated, including viscosity measurements, ultraviolet (UV)-visible spectroscopy, and total organic carbon-total nitrogen (TOC-TN) analysis, to determine the most accurate method for measuring the polymer concentration with the least associated uncertainty. Furthermore, the study investigates the effects of these uncertainties on the final dynamic polymer retention values by applying the propagation of error theory. The effluent polymer concentration was determined using viscosity correlation, UV spectrometry, and TOC-TN analysis, all of which were reliable methods with coefficient of determination (R2) values of ~0.99. The study analyzed the effects of flow through porous media and backpressure regulator on polymer degradation. The results showed that the degradation rates were around 2% for flow through porous media and 16% for mechanical degradation due to the backpressure regulator for all temperature conditions. For the effluent sample, the concentration of polymer was lower when using the viscosity method due to polymer degradation. However, the TOC-TN and UV methods were unaffected as they measured the TN and absorbance at a specific wavelength, respectively. Therefore, all viscosity results were corrected for polymer degradation effects in all tests. During the two-phase coreflooding experiment conducted at 25°C, the accuracy of the UV spectrometry and viscosity measurements was affected by the presence of oil, rendering these methods unsuitable. However, the TOC-TN measurements were able to determine effluent polymer concentration and, subsequently, the retention value. Moreover, the use of glycerin preflush to inhibit oil production during polymer injection in the two-phase studies showed that all three methods were appropriate. The error range was obtained using the propagation of error theory for all the methods. Accordingly, it was noted that the temperature did not affect the dynamic retention values in both single-phase and two-phase conditions. The findings of this study highlight that when adequate oxygen control measures are implemented, the temperature does not exhibit a statistically significant impact on the retention of the ATBS-based polymer under investigation. Furthermore, TOC-TN has been identified as the optimal analytical method due to its minimal uncertainties and ease of measuring polymer concentration under varying experimental conditions.