Benzyl Chloride Research Articles

Study on the corrosion inhibition performance of imidazoline composite inhibitor

AbstractImidazoline quaternary‐ammonium‐salt corrosion inhibitor and thioureido‐imidazoline quaternary‐ammonium‐salt compound corrosion inhibitor were synthesized using oleic acid, diethylenetriamine, benzyl chloride, and thiourea as the raw materials. The resulting samples were characterized by static weight‐loss method, electrochemical polarization curve, X‐ray photoelectron spectrometry (XPS), and scanning electron microscope (SEM). The electrochemical characteristics of the inhibitors' inhibition towards carbon dioxide corrosion were investigated, the major constituents of the protective film formed on the surface of A3 carbon steel by thioureido‐imidazoline compound corrosion inhibitor were analyzed, and the corrosion inhibiting mechanism for thioureido‐imidazoline in hypersaline was explored. The results indicated that thioureido‐imidazoline compound corrosion inhibitor had better corrosion inhibiting effect than imidazoline and can efficiently inhibit the corrosion of A3 carbon steel by CO2‐saturated hypersaline water.

Electrochemical Cobalt-Catalyzed Selective Carboxylation of Benzyl Halides with CO2

The direct, transition metal-catalyzed carboxylation of organohalides with carbon dioxide is a highly desirable transformation in organic synthesis as it utilizes feedstock chemicals and delivers carboxylic acids –among the most utilized class of organic molecules. This article reports the development of a sustainable and selective cobalt-catalyzed electrochemical carboxylation of benzyl halides with CO2 to generate phenyl acetic acids. The success of this transformation is enabled by the development of low-coordinate cobalt/pyrox complexes as electrocatalysts to convert various benzyl chlorides and bromides to their corresponding phenyl/heteroaryl acetic acids with high selectivity over undesired homocoupling of the benzyl chloride. The combination of electroanalytical methods, control reactions, and density-functional theory (DFT) calculations informed the mechanistic analysis of this reaction.

Phosphine-Catalyzed Cross-Coupling of Benzyl Halides and Fumarates.

A phosphine-catalyzed olefinic cross-coupling between benzyl halides and fumarates is described, which affords trisubstituted alkenes in good yields and excellent E-selectivity under metal-free conditions. Mechanistic studies suggest a catalytic cycle involving phosphorus ylide formation, Michael addition, water-assisted hydrogen transfer, and phosphine elimination.

Trisubstituted Triptycenes: Toward the Preparation of Three-Dimensional Dendrimers

A synthesis of benzyl trisubstituted triptycenes is described. These triptycenes are precursors for producing a first generation (G1) poly(triptycylether) dendrimer, a derivative of known poly(arylether) dendrimers. The molecule necessary for the further elaboration into the eventual dendrimer is a carboxylic acid ester triptycene terminated with two ether substituents on another ring; the zero generation (G0). The synthesis begins with formation of the Diels-Alder adduct of benzoquinone and methyl 2-anthroate. This adduct is aromatized under basic conditions and the resulting anion trapped with a benzyl halide as an electrophile to form the trisubstituted triptycene. Access to the trisubstituted system is obtained through a highly improved, efficient and chromatography free preparation of anthracene derivatives, mainly methyl 2-anthroate.

Palladium-Catalyzed Three-Component Coupling Reaction via Benzylpalladium Intermediate.

Transition-metal catalyzed multi-component reactions have captured the attention of researchers in organic synthesis and drug synthesis due to their advantages of simple operation, easy availability of raw materials and without separation of intermediates. Among the multi-component reactions, the three-component processes have been developed into effective organic procedures. This personal account reviews our and other group's studies on the development of three-component coupling reaction for the rapid construction of two new chemical bonds simultaneously via benzylpalladium intermediates. Catalyst-switched three-component reactions of benzyl halides, activated olefins, and allyltributylstannane were successfully conducted to produce the corresponding benzylallylation products. Activation and conversion of carbon monoxide and carbon dioxide via π-benzylpalladium intermediates provide access to a wide range of unsaturated ketones and esters with excellent functional group tolerance. Meanwhile, other methods to produce benzylpalladium intermediates, including Heck insertion of alkenes into arylpalladium complexes, the oxidative addition of benzyl carbonate to palladium complexes and palladium-carbene migratory insertion, were also highlighted.

A Cobalt-Catalyzed Enantioconvergent Radical Negishi C(sp3)–C(sp2) Cross-Coupling with Chiral Multidentate N,N,P-Ligand

A cobalt-catalyzed enantioconvergent radical Negishi C(sp3)–C(sp2) cross-coupling of racemic benzyl chlorides with arylzinc reagents has been developed in good yield with moderate enantioselectivities. This strategy provides an expedient access toward a range of enantioenriched 1,1-diarylmethanes. Key to this discovery is the utilization of a chiral multidentate anionic N,N,P-ligand to strongly coordinate with the cobalt catalyst and tune its chiral environment, thus achieving the enantiocontrol over the highly reactive prochiral alkyl radical species.

Supported Cu(II)-Schiff base: novel heterogeneous catalyst with extremely high activity for eco-friendly, one-pot and multi-component C-S bond-forming reaction toward a wide range of thioethers as biologically active cores.

An effective and proficient process for the synthesis of a variety of thioethers via the one-step reaction of benzyl halides, aryl halides, and thiourea is presented. This strategy is a one-pot procedure to achieve a variety of thioethers without the requirement to thiols as starting compounds. A range of thioethers containing electron donating/electron-withdrawing functional groups were obtained with good to excellent yields under mild conditions. Moreover, the nanocatalyst exhibited excellent recyclability for the reaction, making it more sustainable. One-pot and multi-component synthesis, high yields of final products, green reaction media, high activity of nanocatalyst, simple separation of the products and catalyst, and high regioselectivity are several highlights of this method.

Efficient Synthesis of a New Family of 2,6-Disulfanyl-9-selenabicyclo[3.3.1]nonanes.

The efficient synthesis of a new family of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonanes in high yields has been developed based on 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion generated from bis-isothiouronium salt of 2,6-dibromo-9-selenabicyclo[3.3.1]nonane. The derivatives of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonane containing alkyl, allyl and benzyl moieties have been prepared in 90–99% yields by nucleophilic substitution of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion with alkyl, allyl and benzyl halides. The reaction of nucleophilic addition of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion to alkyl propiolates afforded 2,6-di(vinylsulfanyl)-9-selenabicyclo[3.3.1]nonanes. The conditions for regio- and stereoselective addition of 9-selenabicyclo[3.3.1]nonane-2,6-dithiolate anion to a triple bond of alkyl propiolates have been found. To date, not a single representative of 2,6-disulfanyl-9-selenabicyclo[3.3.1]nonanes has been described in the literature.

Synthesis of branched polyisobutylenes via cationic copolymerization of p‐chloromethylstyrene and isobutylene

AbstractBranched polyisobutylenes (PIBs) with relatively low dispersities (1.4–1.8) and benzylic halide functionalities are synthesized by self‐condensing vinyl cationic copolymerization of p‐chloromethylstyrene (p‐CMS) and isobutylene (IB) coinitiated by TiCl4. It is found that the [IB]/[p‐CMS] feed ratio plays a crucial role for the initiating behavior of p‐CMS: the initiation arising from p‐CMS is suppressed at [IB]/[p‐CMS] ≥17; in contrast, the pendant benzyl chloride moiety of p‐CMS monomer in the formed copolymer chains can initiate branching reactions. The resulting branched PIBs are of a gradient composition as well as a gradual increase in branching density due to large disparity in reactivity ratios. This strategy is successfully employed to create branched PIBs with low to moderate molecular weights (Mn, 5 k–78 k Da) through controlling the monomer/initiator mole ratio. However, it is shown that this method failed to obtain branched PIBs with high Mn, bearing a complicated copolymerization mechanism.

Preparation and characterization of the side-chain quaternized poly(phthalazinone ether ketone)s with phenyl groups for vanadium redox flow battery

A series of new side-chain substitution poly (phthalazinone ether ketone)s with benzyl chloride moieties (CMPPEK-P) were synthesized through the chloromethylation of poly (aryl ether ketone)s containing pendant phenyl groups (PPEK-P). The content of side-chain phenyl groups in the PPEK-P was controlled by the feed ratios of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-ketone to 4-(3-phenyl-4-hydroxyphenyl)-2,3-phthalazin-1-ketone during polymerization process. The chemical structures of PPEK-P and CMPPEK-P were assessed by 1H NMR and FTIR spectroscopy. Based on the characterization results, a new anion exchanged membrane (QAPPEK-P) was prepared by amination reaction used for vanadium redox flow batteries. The ion-exchange capacity of QAPPEK-P membranes (0.21–0.88 mmol g−1) was related to the content of side-chain phenyl groups. The cell performance of QAPPEK-P membrane was increased with the increasing values of IEC. Compared with Nafion 115, QAPPEK-P-50 displayed higher voltage efficiency (82.8% vs. 76.9%) and energy efficiency (80.2% vs. 76.5%) at the current density of 140 mA/cm2. Furthermore, the efficiencies of QAPPEK-P-50 remained stable for 150 cycles and there was no obvious change in its structure.

Cu2+ ion crosslinked carboxymethylcellulose/diatomite composite beads as an efficient catalyst for CuAAC reactions

Cu2+‐crosslinked carboxymethylcellulose/diatomite composite beads (CuII@CMC/DE) were prepared in simple and efficient way using ionic crosslinking techniques. In CuII@CMC/DE beads, diatomite serves as a reinforcing filler, and divalent copper cation acts as crosslinking agent. The chemical structure and morphology of as‐fabricated CuII@CMC/DE beads were well characterized using various techniques such as ICP, FT‐IR, XRD, SEM, EDS, elemental mapping, TEM, XPS, and TGA. The CuII@CMC/DE beads exerted superior catalytic performance in CuAAC reactions of benzyl halides, sodium azide, and alkynes to yield regioselected 1,4‐disubstitued‐1,2,3‐triazoles in excellent yields under green conditions. In these resultant catalytic composite beads, Cu2+ was used not only as a crosslinking agent but also as a metal catalyst for CuAAC reaction. The composite beads can be easily separated by filter and reused at least four times without any significant decrease on its activity and selectivity.

Relative activity of metal cathodes towards electroorganic coupling of CO2 with benzylic halides

Electrochemical reduction of benzylic halides represents a convenient route to generating carbanions for their subsequent coupling with CO2 to obtain various carboxylic acids. Despite the industrial prospects of this synthetic process, it still lacks systematic studies of the efficient catalysts and reaction media design. In this work, we performed a detailed analysis of the catalytic activity of a series of different metal electrodes towards electroreduction of benzylic halides to corresponding radicals and carbanions using cyclic voltammetry. Specifically, we screened and summarized the performance of 12 bulk metal cathodes (Ag, Au, Cu, Pd, Pt, Ni, Ti, Zn, Fe, Al, Sn, and Pb) and 3 carbon-based materials (glassy carbon, carbon cloth, and carbon paper) towards electrocarboxylation of eight different benzylic halides and compare it to direct CO2 reduction in acetonitrile. Extensive experimental studies along with a detailed analysis of the results allowed us to map specific electrochemical properties of different metal electrodes, i.e., the potential zones related to the one- and two-electron reduction of organic halides as well as the potential windows where the electrochemical activation of CO2 does not occur. The reported systematic analysis should facilitate the development of nanostructured electrodes based on group 10 and 11 transition metals to further optimize the efficiency of electrocarboxylation of halides bearing specific substituents and make this technology competitive to current synthetic methods for the synthesis of carboxylic acids.

Copper immobilized on biomimetic assembled calcium carbonate/carboxymethylcellulose hybrid: a highly active recoverable catalyst for CuAAC reactions

A novel copper immobilized on biomimetic assembled carboxymethylcellulose/calcium carbonate hybrid (CuII@CMC/CaCO3) as an efficient heterogeneous catalyst for the synthesis of 1,2,3-triazoles has been described herein. The fabrication of CuII@CMC/CaCO3 is accomplished through a bioinspired mineralization process using sodium carboxymethylcellulose (CMC-Na) as the template and ion exchange agent, while the metathesis, nucleation, assemble, hybridization, and immobilization of Cu(II) occurred by successful treatment with CaCl2, Na2CO3, and CuSO4 in water at room temperature. The resultant CuII@CMC/CaCO3 hybrid was well characterized by various analyses such as FT-IR, XRD, SEM, EDX, EDX-mapping, TEM, and TGA techniques. In the presence of low copper loading of CuII@CMC/CaCO3 hybrid, benzylic halides, azide, and alkynes proceeded smoothly to afford 1,4-disubstituted 1,2,3-triazoles in high yields. The catalyst can be conveniently recovered from the reaction mixture by filter and reused for at least 5 consecutive runs with a slight drop in its catalytic activity. The remarkable activity and stability of the catalyst may be attributed to the coordination of both carboxyl and hydroxyl groups of the hybrid of CMC/CaCO3.

Synthesis of Shape-Controllable Anisotropic Microparticles and "Walnut-like" Microparticles via Emulsion Interfacial Polymerization.

Anisotropic microparticles have plenty of applications for their asymmetric structure and precisely modified surface. In our research, the uniform anisotropic microparticles with benzyl chloride group were synthesized successfully via emulsion interfacial polymerization. By varying the degree of cross-linking and the concentration of slightly hydrophilic monomer 4-vinyl benzyl chloride (VBC), several types of microparticles with different concavities and different shapes of microparticles (hemisphere, bowl-like, egg-like, etc.) were obtained. Nanoporous microparticles with a walnut-like heterostructure were achieved with modified hydrophilic seeds with the same strategy. The potential applications of shape-controllable fluorescent microparticles and surface modification of microparticles by thiol-click reaction were explored. The modified microparticles achieved in this study are very useful in labeling, tracing, protein separation, and other biomedical fields.

Synthesis of Mono-Ketone Curcumin Analogs from 3-Benzyloxybenzaldehyde and their Activity Assay as Inhibitor of α-Amylase

Synthesis, characterization, and biological evaluation of mono-ketone curcumin analogs as an inhibitor of α-amylase enzyme have been conducted. This research was initiated by synthesizing 3-benzyloxybenzaldehyde from 3-hydroxybenzaldehyde using benzyl chloride, potassium iodide, and potassium carbonate in dimethylformamide under reflux condition for an hour. Synthesis of monoketone curcumin analogs was performed through Claisen-Schmidt reaction by refluxing 3-benzyloxybenzaldehyde with acetone (analog A), cyclopentanone (analog B), and cyclohexanone (analog C) using potassium hydroxide 5% as a catalyst for an hour. The structures of the products were elucidated by FTIR, MS/MS,1H-NMR, and13C-NMR. Mono-ketone curcumin analogs were evaluated for their activity assay towards inhibition of α-amylase enzyme. The inhibition type of mono-ketone curcumin analogs was also investigated. The inhibition results of monoketone curcumin analogs were compared to acarbose as a positive control. The results showed that 3-benzyloxybenzaldehyde and mono-ketone curcumin analogs (A, B, and C) yielded in 90.2, 89.7, 97.4, and 94.6%, respectively. The inhibitory activity of curcumin analog C was higher than the acarbose and other curcumin analogs (A and B). The inhibition types of mono-ketone curcumin analogs (A, B, and C) and acarbose were considered as uncompetitive inhibitors.

Towards a Strategy for the Synthesis of Polymeric Ionic Liquids with a Bulk Anion in Various Reaction Media

The interest in polymerizable ionic liquids of researchers is due to their unique properties, such as good thermal stability, low vapor pressure, and wide potential window of stability. The complex of these properties determines the prospect of using ionic liquids and polymers based on them in the technology of membrane separation. This article describes the synthesis of monomeric ionic liquids (IL) containing quaternary amino groups, pyridine, and imidazole groups based on vinyl benzyl chloride (conversion was 95%). Further, on their basis, polymer ionic liquids were obtained by the method of free radical polymerization with bulky anionic substituents. Proof of the formation of polimeric IL was carried out by NMR and FTIR spectroscopy methods. The molecular weight of the IL was determined by gel permeation chromatography and reached ~ 140,000. An anion exchange reaction was carried out to replace the Cl anion with Tf2N.

The effect of ionic liquid containing AlCl3 catalytic systems on the microstructure and properties of polyalphaolefin based lubricants

A new class of ionic liquid (IL) containing AlCl3 catalysts was synthesized from 1-methylimidazole, and different alkyl chlorides, including: 1-butyl chloride, cyclohexyl chloride and benzyl chloride, named as IL-But/AlCl3, IL-CH/AlCl3 and IL-Benz/AlCl3, respectively. The as-synthesized catalysts were employed along with half dosage of AlCl3 in the 1-decene oligomerization to related polyalphaolefins (PAOs), as a less-toxic alternative to the conventional, corrosive and toxic AlCl3 and BF3 catalysts. Besides aiming to achieve new, safer and cost-effective catalyst, the microstructure-flow properties of the synthesized oils were studied by using various techniques. Results revealed that the catalytic efficiency of IL/AlCl3 catalysts can be tuned by the proper choice of alkyl chloride. IL-Benz/AlCl3 and IL-CH/AlCl3 yielded more uniformly structured PAOs with low molecular weight, kinematic viscosity (KV), and short chain branching, but, higher viscosity index (VI) values. However, IL-CH/AlCl3 resulted PAO whose characteristic was very close to the one obtained by neat AlCl3. Synthesized from greener IL/AlCl3 system, in which the loading of AlCl3 as catalyst is halved, together with enabling to control PAO microstructure by proper selection of IL ligand are substantial achievements of the suggested catalytic systems.

Single-Step Approach toward Nitrones via Pyridinium Ylides: The DMAP-Catalyzed Reaction of Benzyl Halides with Nitrosoarenes.

A single-step approach is reported for the preparation of nitrones from benzyl halides and nitrosoarenes via pyridinium ylides, utilizing 4-dimethylaminopyridine (DMAP) catalyst and mild reaction conditions (Li2CO3, dimethylacetamide, and room temperature). The reaction provides both keto- and aldonitrones in high yields with a wide scope for benzyl halides and nitrosoarenes. In the same reaction system, 2-methyl-2-nitrosopropane, which does not have an aryl group, also affords the corresponding N-tert-butyl nitrones from primary benzyl bromides that have an electron-withdrawing group. As an application of the reaction, methyl 2-bromo-2-phenylacetate was used to prepare the corresponding isoxazolidine by a sequential one-pot synthesis.

Characteristics of tailpipe volatile halogenated hydrocarbon (VHC) emissions from in-use vehicles during real-world driving.

Vehicular emissions have become a primary anthropogenic source of urban atmospheric volatile halogenated hydrocarbons (VHCs) with the rapid increase of vehicle population, while characteristics of the VHC emissions from different vehicles were rarely systematically investigated. In this study, the on-road tailpipe emissions were sampled from seven in-use vehicles, including two light-duty gasoline vehicles (LDGV), three light-duty diesel trucks (LDDT), one heavy-duty diesel truck (HDDT), and a liquefied petroleum gas-electric hybrid bus (LPGB), using a portable emission measurement system (PEMS) combined with summa canisters, and 35 individual VHC species were identified by a gas chromatography mass spectrometry detector (GC-MSD). Results showed that VHC emissions under urban driving conditions were much higher than those on the suburban roads and highways. The VHC emission factors of LDGV were 1.2 ± 0.34 mg/km and 3.6 ± 1.5, 6.8 ± 0.89, and 1.6 ± 0.28 mg/km for LDDT, HDDT, and LPGB, respectively. For the LDGV, chlorobenzene, 1,2-dichloroethane, and hexachlorobutadiene were the top three VHC species. 1,2-Dichloroethane, trichloromethane, and methyl chloride were the main VHC constituents in the LDDT. Chlorobenzene was the most abundant VOC species for the HDDT, followed by 1,2-dichloroethane and 1,4-dichlorobenzene. The major species for LPGB were 1,2,4-trichlorobenzene, carbon tetrachloride, and benzyl chloride. The major tailpipe VHC species obtained in this study were partial consistent with previous studies with different test methods. The results provide an initial evaluation of the tailpipe VHC emissions, which may provide experimental data support for the refined source apportionment of atmospheric VHCs and the control of vehicular VHCs.

Catalytic Benzylation Reactions: From C—H Bond Activation to C—N Bond Activation

AbstractTransition‐metal mediated activation of inert chemical bonds is an ongoing topic in homogeneous catalysis. In view of the abundance and accessibility of alkylarenes and benzylamines, the use of them as benzyl source in catalytic benzylation reactions via benzylic C—H and C—N bond activation is highly desirable. Indeed, compared with the traditional approaches with benzyl halide as the substrates, benzylation reactions via C—H and C—N bond cleavage provide more efficient, atom‐economic strategies to access myriads of synthetically important molecules. In this account, our group's efforts on catalytic benzylation reactions via directed C—H activation, nondirected C—H activation and C—N bond activation are summarized. What is the most favorite and original chemistry developed in your research group?Palladium‐catalyzed aminal chemistry.How do you supervise your students?Discuss with my students and encourage them to think about where the scientific problem is.What is the most important personality for scientific research?Honesty, curiosity and passion.What are your hobbies?Reading and playing badminton.Who influences you mostly in your life?My parents, who always inspire me to go forward.What is your favorite journal(s)?Journals that fairly review the manuscripts and publish inspiring, innovative research results.