Search

The forward osmosis (FO) membrane exhibits great performance degradation when contacting with chlorine solutions. The damage of chlorine to membrane material will seriously reduce the lifetime of the membrane and increase the cost of membrane treatment technology. Here, we prepared chlorine-stable membranes by a covalent modification method with cyclohexylamine. The cyclohexylamine observably changed the surface morphology, the roughness (arithmetic average) of the membrane decreased from 22 to 17.2 nm. The addition of cyclohexylamine produced a denser sacrificial layer of short chain polyamide, which made modified membranes possess significantly better chlorine resistance with slightly declined water flux. The water flux of the optimal modified membrane was 10.78 Lm−2 h−1, only 13% less than that of the pristine membrane. Importantly, after 20,000 ppm·h chlorine exposure, the membrane with 1.5 wt% cyclohexylamine had a salt rejection of 77.2% and showed 26.0% lower water flux than pristine TFC (thin film composite) membrane in FO mode. Notably, the grafting membranes could maintain a high performance under acidic chlorination conditions. The membrane with best performance had a salt rejection of 81.6%, exhibiting 24.4% higher salt rejection than pristine membrane with 20,000 ppm·h chlorine exposure at a pH of 4. The cyclohexylamine endowed the FO membrane with better chlorine resistance, making it attractive for the development of chlorine-resistant membrane for environmental and desalination processes. HIGHLIGHTS The addition of cyclohexylamine produced a chlorine-resistant sacrificial layer.; The 1.0 wt% addition of cyclohexylamine did not significantly decrease the water flux of the forward osmosis membrane.; Under acidic conditions, cyclohexylamine could still significantly improve the chlorine resistance of forward osmosis membranes.

In the conventional method of synthesis by using cyclohexylamine (CA) as template produces in the pore range of 0–3 nm. To enlarge the pore size which is suitable for biodiesel synthesis, the modif...

Organic and inorganic structure-directing agents (SDAs) impact Al distributions in zeolite, but the insights into how SDAs manipulate Al distribution have not been elucidated yet. Herein, the roles of different SDAs such as cyclohexylamine (CHA), hexamethylenimine (HMI), and Na+ in selective Al substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR. The results demonstrate that MCM-49 synthesized with HMI shows relatively more T6 and T7 Al, while more T2 Al is observed using CHA. The formation of T2 Al in both MCM-49(HMI) and MCM-49(CHA) is derived from Na+, while protonated HMIs show bias in incorporation of T6 and T7 Al. Most HMIs are occluded in protonated status, and about half of CHAs are occluded in nonprotonated status. The close spatial proximity between nonprotonated CHAs and Na+ synergistically promotes the formation of zeolite structure, leading to more Na+ ions occluded in the zeolite channel with preferential T2 Al substitution.

This work deals with a study of the effect of temperature on the cyclohexylamine disproportionation to dicyclohexylamine, conjointly with the thermodynamic analysis of this process. The laboratory experiments were carried out in a glass tubular continuous-flow reactor in a gaseous phase at the reaction temperature 433–463 K over a nickel catalyst. The results show, that the temperature has a trifling effect on equilibrium conversion of cyclohexylamine. However, temperature affects the formation of hydrocarbons, benzene and cyclohexane, and dehydrogenation products of dicyclohexylamine, i.e. N-cyclohexylidenecyclohexanamine and N-phenylcyclohexylamine. The latter one is the dominant product of dicyclohexylamine dehydrogenation. The disproportionation of cyclohexylamine has slightly exothermic character. At the experimental reaction temperature range, the cyclohexylamine disproportionation is spontaneous reaction and other reactions of this process are non-spontaneous.

Aim: Novel quinazolin-4(3H)-one heterocycles were synthesized and assessed for their anti-diabetic activity. Non-enzymatic glycosylation of haemoglobin assay was carried out to identify their potential as anti-diabetic. The cyclization of quinazolinone-4(3H)-one heterocycles was achieved, whereas carbon-carbon cross coupling reactions were carried out using Sonogashira and Suzuki-Miyaura reaction conditions and characterized with analysis. This synthesis method afforded corresponding 2, 3 and 6 substituted quinazolin-4(3H)-ones (3a to 3m) with excellent yields. Methods: 2-Amino-6-bromobenzoic acid was used as a substrate which was converted to corresponding benzamide derivatives (1a-1b) by reaction with benzylamine or cyclohexylamine using acid-amine reaction, followed by cyclization and oxidation using suitable aldehyde in DMSO under microwave condition to give bromo substituted quinazolin-4(3H)-ones (2a-2c), which were cross coupled to suitable terminal alkyne with palladium catalyst as well as copper co-catalyst using Sonogashira condition to obtain desired (3a-3h) and suitable boronic acid with palladium catalyst using Suzuki-Miyaura condition to obtain desired (3i-3m). All synthesized compounds were characterized by FTIR, proton NMR, LC-MS analysis and evaluated for in vitro anti-diabetic activity using non-enzymatic glycosylation of haemoglobin assay. Results: Compounds 3m showed good inhibition of glycosylation of haemoglobin which in turn suggest good anti-oxidant potential on metabolism of glucose and hence lower glucose concentration. It showed IC50 value of 35.91±0.82 µg/mL which was comparable to the standard alpha tocopherol (34.47±0.87µg/mL). Conclusion: In-vitro non-enzymatic glycosylation of haemoglobin method is one of important assays to judge the control of diabetes. The haemoglobin present in RBCs has an affinity to bind with glucose. The greater the glucose level in blood, more amount of glucose-bound (called glycosylated) haemoglobin will be formed. Accordingly, presence of lower concentration of glycosylated haemoglobin is a sure guide to the lower concentration of glucose in the blood. Synthesized compounds (3a-3m) lower the blood glucose level and 3m has highest potential among those which can be further developed as potent anti-diabetic.

Amine dehydrogenases (AmDHs) are one of the key emerging enzymes used in the synthesis of various amines with the expense of only one ammonium ion as an amino donor, thereby, generates only water molecule as a by-product. Currently, most available AmDHs have been created through protein engineering using the existing natural L-amino acid dehydrogenase, and native AmDHs are rarely reported. In this study, a novel native AmDH from Laribacter hongkongensis (LhAmDH) was identified based on the GenBank database using a sequence-driven approach. LhAmDH showed a good activity towards various carbonyl compounds such as cyclohexanone (170 mU/mg) and isovaleraldehyde (214 mU/mg). The reductive amination of model substrate, cyclohexanone (up to 100 mM) into cyclohexylamine was successfully performed in LhAmDH and FDH system with > 99% conversion using Escherichia coli whole-cell as well as purified enzymes. Furthermore, three enzymes cascade (ω-transaminase, LhAmDH, and FDH) was designed to produce chiral amine from the corresponding ketone using inexpensive ammonium formate as sole sacrificial agent. The active site of LhAmDH residues were predicted using the protein structure homology model building program SWISS-MODEL server. In the docking analysis, cyclohexanone is well-orientated with −5.4 kcal/mol of binding energy and 3.16 A distance from side chain of E104, which is a key residue for interacting ammonia and substrate. This LhAmDH model can be used as a promising template to produce chiral amines through semi-rational design.

[Image: see text] To improve the metabolic stability profile of BMS-741672 (1a), we undertook a structure–activity relationship study in our trisubstituted cyclohexylamine series. This ultimately led to the identification of 2d (BMS-753426) as a potent and orally bioavailable antagonist of CCR2. Compared to previous clinical candidate 1a, the tert-butyl amine 2d showed significant improvements in pharmacokinetic properties, with lower clearance and higher oral bioavailability. Furthermore, compound 2d exhibited improved affinity for CCR5 and good activity in models of both monocyte migration and multiple sclerosis in the hCCR2 knock-in mouse. The synthesis of 2d was facilitated by the development of a simplified approach to key intermediate (4R)-9b that deployed a stereoselective reductive amination which may prove to be of general interest.

In this work, the solubilities of carbamazepine (CBZ) (form III) in ethyl acetate, methyl acetate, ethylene glycol, chloroform and cyclohexylamine were determined by laser monitoring techniques at pressure above sea level, and the solubility data of CBZ (form III) in different pure solvents were fitted by the Modified Apelblat model and λh model. The result shows that the solubility of CBZ (form III) in five solvents increases as temperature rises, and the solubility in chloroform was the largest. The experimental solubility values of CBZ (form III) in ethyl acetate, methyl acetate, chloroform and cyclohexylamine were in better agreement with the simulated fitting values of the λh model. For ethylene glycol, the σ value was much larger than the other four solvents, and it can be seen from the λh model that ethylene glycol was closer to the ideal solution system than the other four solvents.

Alicyclic amines are widely used in several types of industries, and considerable attention has been devoted to possible environmental pollution by alicyclic amines in hypersaline industrial wastewater. In this study, a new hypersaline tolerant bacterial TYUT067 capable of growing in liquid basal salt medium with cyclohexylamine (CHAM) as the sole carbon source and energy source, was isolated from soil, and discovered with highly efficient CHAM degrading ability. The strain TYUT067 was identified as Paenarthrobacter sp. based on 16S rDNA gene sequence, and its degradation characteristic was examined. The results revealed that the isolated TYUT067 could grow well under pH range of 6.5–10.0, temperature from 20 °C to 30 °C. For degradation of 60 mM of cyclohexylamine, 100% degradation could be finished within 120 h. The TYUT067 could degrade 10 mM CHAM under hypersaline conditions (3–5% NaCl, w/v), revealed the hypersaline tolerance of TYUT067. Different type of amines was also tested with TYUT067, the degradations of >90% were achieved toward several alicyclic amines. The current results suggested that TYUT067 was a potential species could be efficiently used for the degradation of alicyclic amines and might be applicable to a hypersaline wastewater treatment system for the removal of alicyclic amines. HIGHLIGHTS A new cyclohexylamine degradation bacterial strain TYUT067 was isolated from soil environment.; The isolated TYUT067 is an alkali-tolerant strain and mesophilic microorganisms.; The isolated TYUT067 can degrade CHAM under hypersaline environment.; The isolated TYUT067 can degrade various alicyclic amines.

A simple and highly efficient method for manufacturing cyclohexanone oxime from solvent-free liquid-phase aerobic oxidation of cyclohexylamine over a glucose-modified TiO2 catalyst had been develop...

Two groups of commercially available Ni- and Pd-based catalysts were used for the direct amination of cyclohexanol (CHOL) with NH3 as aminating agent and in the presence of H2, aiming the selective production of cyclohexylamine (CHA) and aniline. The fresh catalysts were characterized in terms of metal loading, support composition (prevailing SiO2 and Al2O3) and metallic dispersion. Ni-based catalysts revealed to be highly active while Pd-based were more selective towards aniline, however requiring higher temperatures and catalyst loading to reach significant CHOL conversions (from 17 up to 67 %). The activity of the catalysts is intrinsically related to their metallic dispersion regardless the metal loading. The Ni-based catalyst with 46 wt. % of Ni is the most promising once it presents higher turnover frequency (TOF) values, as 10 fold high, particularly related to the ratio of desired to undesired by-products. Moreover, operating conditions considerably affect catalysts’ performance.

Herein, the catalytic performance of palladium nanoparticles grafted on the polymeric TSNH2 (Tentagel-S-NH2) resin was investigated for continuous-flow liquid-phase hydrogenation of two industrially relevant chemicals: 2-methyl-3-butyn-2-ol and nitrocyclohexane. We investigated the effect of process parameters such as temperature and pressure on PdTSNH2 activity and selectivity. Depending on the reaction conditions, well-dispersed PdNPs with average size of about 2 nm have shown very high flexibility in terms selectivity toward the desired products: 2-methyl-3-buten-2-ol or 2-methyl-2-butanol in the case of 2-methyl-3-butyn-2-ol hydrogenation and cyclohexanone oxime or cyclohexylamine as the main product in the case of nitrocyclohexane conversion. The optimal reaction conditions for 2-methyl-3-buten-2-ol formation were estimated at 25 °C and 5 bar, and in the case of cyclohexanone oxime formation at 40 °C and 10 bar. We demonstrated the general trend in the catalytic performance of 2.2 wt% Pd grafted on Tentagel-S-NH2. Independently of the hydrogenated substrate, the increase in conversion leads to decreased selectivity to 2-methyl-3-buten-2-ol and cyclohexanone oxime at the expense of increasing the selectivity to 2-methyl-2-butanol or cyclohexylamine. Graphic abstract

Several protonated amine-templated uranyl oxalate complex were designed and synthesized, and the structures and optical properties were investigated by different techniques. The amine templates have a significant structural-oriented effect on the construction of uranyl oxalate complex. When alkyl substituents are added to N atoms, templated amines will be more flexible and helps build the crystals with a denser structure and a better thermal stability. The crystal properties are closely related to the amine templates: 4# (using N,N-diethylcyclohexylamine as the template) has a potential application as CO gas storage materials; 1# (using cyclohexylamine as the template) has a potential application for ultraviolet irradiation chemical dosimeter.

Selective hydrogenation of aromatic amines, especially chemicals such as aniline and bis(4-aminocyclohexyl)methane for non-yellowing polyurethane, is of particular interests due to the extensive applications. To conquer the existing difficulties in selective hydrogenation, the Ru0-Ruδ+/CeO2 catalyst with solid frustrated Lewis pairs was developed for aromatic amines hydrogenation with excellent activity and selectivity under relative milder conditions. The morphology, electronic and chemical properties, especially the Ru0-Ruδ+ clusters and reducible ceria were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), CO2 temperature programmed desorption (CO2-TPD), H2 temperature programmed reduction (H2-TPR), H2 diffuse reflectance Fourier transform infrared spectroscopy (H2-DRIFT), Raman, etc. The 2% Ru/CeO2 catalyst exhibited good conversion of 95% and selectivity greater than 99% toward cyclohexylamine. The volcano curve describing the activity and Ru state was found. Owning to the "acidic site isolation" by surrounding alkaline sites, condensation between the neighboring amine molecules could be effectively suppressed. The catalyst also showed good stability and applicability for other aromatic amines and heteroarenes containing different functional groups.

The direct synthesis of cyclohexylamine via the hydrogenation of nitrobenzene over monometallic (Pd, Ru or Rh) and bimetallic (PdxRu1−x) catalysts was studied. The Pd0.5Ru0.5-PVP catalyst was the most effective catalyst for this reaction. The catalyst can be reused and applied for the synthesis of N-aryl pyrroles and quinoxalines from nitrobenzenes.

1,3-Dichloro-1,3-bis(dimethylamino)propenium salts react with primary amines to give different products depending on the structure of the amine. Reactions in which the primary amine is bonded to a tertiary carbon (tert-butylamine and 1-adamantylamine) result in 1,1-bis(dimethylamino)-3,3-bis(alkylamino)propenium salts which form via a 1,3-dimethylamino shift. In contrast, the reactions in which the primary amine is bonded to a secondary carbon (cyclohexylamine, cyclopentylamine, and sec-butylamine) result in 1-(ylidene)amino-1,3-bis(dimethylamino)propenium salts which form via an intramolecular hydride shift. All of the synthesized compounds have been fully characterized using spectroscopic methods, including single crystal X-ray diffraction. Finally, the mechanisms of the intramolecular rearrangements have been investigated computationally at the ωB97X-D/6-311G(d,p) level of theory, suggesting that the reactions proceed through putative keteniminium species.

Two bidentate PNP ligands N,N-bis(di-p-tolylphosphino)cyclohexylamine (Cy-pTolPNP) (1) and N,N-bis(di-p-tolylphosphino)cyclobutylamine (Cb-pTolPNP) (2) were synthesized and crystallized. Coordination to the fac-[MI(CO)3]+ core (M = Re, 99Tc) yielded fac-[Re(Cy-pTolPNP)(CO)3Br] (1A), fac-[99Tc(Cy-pTolPNP)(CO)3Cl] (1B), fac-[Re(Cb-pTolPNP)(CO)3Br] (2A) and fac-[99Tc(Cb-pTolPNP)(CO)3Cl] (2B) in relatively good yields (56 to 86 %): The structures of 1, 2, 1A and 1B were studied by single crystal X-ray crystallography. Preliminary mitochondrial/antimicrobial evaluation of the free ligand (N,N-bis(di-p-tolylphosphino)-cyclohexylamine) (1) and its respective fac-[Re(CO)3]+ (1A) complex indicates that neither the free ligand nor the complex was active against selected fungi Eremothecium ashbyii and Nadsonia fulvescens. In addition, all four compounds were found to have no activity against Gram-positive and Gram-negative bacterial species. These biological results are essential to the understanding of how these types of complexes behave and show they are perfectly stable in the evaluated bio-environments. In addition, the results indicate that these ligands and complexes may present themselves as excellent models for radiotoxicity studies using technetium-99m, but more specifically, rhenium Re-186 and Re-188.

We report a highly atom-efficient integrated cofactor/co-product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω-amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ϵ-caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole-cell biocatalysts. This cascade could be an alternative for bio-based production of ω-amino acids and corresponding lactam compounds.

In this work, a new mesoporous silicon sulfonic acid catalyst derived from silicic acid has been successfully prepared by the chemical bonding method. The physico-chemical properties of mesoporous silicon sulfonic acid catalysts have been systematically characterized using various techniques. The results demonstrate that sulfonic acid groups have been grafted on silicic acid by forming a new chemical bond (Si-O-S). The mesoporous silicon sulfonic acid exhibits excellent catalytic performance and stability in the vapor phase hydroamination reaction of cyclohexene with cyclohexylamine. Cyclohexene conversion of 61% and 97% selectivity to dicyclohexylamine was maintained after running the reaction for over 350 h at 280 °C. The developed mesoporous silicon sulfonic acid catalyst shows advantages of low cost, superior acid site accessibility, and long term reactivity stability. Moreover, a possible catalytic hydroamination reaction mechanism over silicon sulfonic acid was suggested. It has been demonstrated that the sulfonic acid groups of the catalyst play an important role in the hydroamination. The present work provides a simple, efficient, and environmentally friendly method for the hydroamination of cyclohexene to valuable dicyclohexylamine, which also shows important industrial application prospects.

Thickener formulation plays a significant role in the performance characteristics of grease. The polyurea greases (PUGs) were synthesized using mineral oil (500SN) as the base oil, and by regulating the reaction of diphenylmethane diisocyanate (MDI) and different organic amines. The as-prepared PUGs from the reaction of MDI and cyclohexylamine/p-toluidine exhibit the optimum physicochemical and friction-wear properties, confirming that the regulation of thickener formulation can improve the performance characteristics of grease, including friction reduction, wear, corrosion resistance, and load-carrying capacity. The anti-corrosion and lubrication properties of as-prepared PUGs depend on good sealing functions and a boundary lubrication film (synergy of grease-film and tribo-chemical reaction film), as well as their chemical components and structure.

The high-temperature (HT) and low-temperature (LT) hydrothermal stabilities of molecular-sieve-based catalysts are important for the selective catalytic reduction of NOx with ammonia (NH3-SCR). In this paper, we report a catalyst, Cu2+ loading SAPO-17, synthesized using cyclohexylamine (CHA), which is commercially available and inexpensive and is utilized in NH3-SCR reduction for the first time. After systematic investigations on the optimization of Si and Cu2+ contents, it was concluded that Cu-SAPO-17-8.0%-0.22 displays favorable catalytic performance, even after being heated at 353 K for 24 h and at 973 K for 16 h. Moreover, the locations of CHAs, host–guest interaction and the Bronsted acid sites were explored by Rietveld refinement against powder X-ray diffraction data of as-made SAPO-17-8.0%. The refinement results showed that two CHAs exist within one eri cage and that the protonated CHA forms a hydrogen bond with O4, which indicates that the proton bonding with O4 will form the Bronsted acid site after the calcination.

Purpose A novel compound was synthesized by cyclohexylamine, acetophenone and cinnamaldehyde through Mannich reaction in laboratory to use as corrosion inhibitor for steel in acidification process. Design/methodology/approach The corrosion and inhibition of 13Cr stainless steel in conventional acidification solution were investigated by electrochemical measurements and soaking experiments. The corrosion appearance was observed with scanning electron microscope on the whole surface of 13Cr stainless steel in 20% HCl solution, and the protection film was confirmed on the surface in presence with inhibitor. Findings Results manifested that the inhibitor C23H27NO can effectively inhibit the corrosion reaction by forming an adsorption layer function as a barrier. Polarization curves indicated that the mixed inhibitor can reduce anodic dissolution and cathodic hydrogen evolution reactions simultaneously. The results of impedance measurements indicated that this inhibitor cannot change the corrosion mechanism of 13Cr stainless steel in 20% HCl solution. The results of the study can provide a theoretical basis for the application of 13Cr stainless steel in conventional acidification solutions during oil well acidification construction process. Originality/value A novel compound was synthesized by cyclohexylamine, acetophenone and cinnamaldehyde through Mannich reaction in laboratory to use as corrosion inhibitor for steel in acidification process. The corrosion and anti-corrosion mechanism of 13Cr steel in acid solution was proposed.

Cyclohexylamine (CHA) is used as an important raw material in chemical industries. Since the production of CHA requires a high temperature and excess amounts of hydrogen gas (H2) and ammonia, the development of a simple reaction operated under milder conditions using a safe compound is indispensable for achieving sustainable chemistry. A highly selective ring hydrogenation of aniline (AN) to CHA over a titanium(IV) oxide photocatalyst having a co-catalyst in water at room temperature, in which oxalic acid was used as the hydrogen source in place of H2, is described in this paper. Among TiO2 photocatalysts having co-catalysts, Rh-TiO2 showed high activity for CHA production, while Pd-TiO2 and Ru-TiO2 showed negligible activity. When a bimetallic photocatalyst, Ru/Pd-TiO2, was used, the yield was larger than that when Rh-TiO2 was used. Metal particles loaded on TiO2 were observed by using TEM, and electronic states of Ru and Pd were evaluated by using XPS. Interactions among metal, AN and CHA were investigated through adsorption experiments. Based on the results, active sites for AN hydrogenation are discussed.

Background A new and simple effervescent CO2-table-induced switchable hydrophilicity solvent extraction method (CI-SHS) was used for the preconcentration of rhodamine B (RB). Objective The main theme of the proposed method to disperse green solvent by in situ CO2-table system overcome on the contamination and to avoid the dispersion by using different chemicals. Methods Switchable hydrophilicity solvent (N, N-Dimethyl cyclohexylamine) was dispersed in an aqueous solution by reaction of CO2-table of sodium carbonate and citric acid to enhance the contact area between two medium, which radically improved the extraction capacity of the RB from aqueous medium to switchable solvent. The phase separation was achieved by simple heating not by centrifugation that makes a change on hydrophilicity to hydrophobicity. The supernatant-enriched RB- N, N-Dimethyl cyclohexylamine phase was withdrawn and injected into the UV glass cells. The absorbance was measured at 542. Results Limit of detection and enhancement factor were achieved to be 0.042 and 50 µg/L. Validity and accuracy of the method verified by analysis of real samples by the spiking addition method. The relative standard deviation was obtained at 3.2%. The method was applied to food and soft drink samples. Conclusions This method offers high sensitivity, selectivity, accuracy, and precision for the separation, preconcentration, and spectrophotometric determination of RB. Simple, fast, low-cost, and green extraction method was developed. Highlights High enrichment factor and lower detection limits were observed in this microextraction method. Present method is sensitive, selective, very accurate, and precise.

Reactions of 2-[1-ethyl-3-methyl-7-(thietan-3-yl)- and 2-[1-ethyl-3-methyl-7-(1,1-dioxothietan-3-yl)xanth- 8-ylthio]acetic acids with amines (diethylamine, monoethanolamine, diethanolamine, triethanolamine, piperidine, cyclohexylamine, and benzylamine) gave 42 – 89% yields of 2-[1-ethyl-3-methyl-xanth-8-ylthio]- acetate salts containing thietanyl and dioxothietanyl rings. The structures of the synthesized compounds were confirmed using IR and PMR spectroscopy. The synthesized compounds exhibited anti-aggregation activity.

A series of new α-aminophosphonates was synthesized based on the acid-catalyzed Kabachnik–Fields reaction involving diethyl phosphite, cyclohexylamine and substituted benzaldehyde. Structure of the reaction products was established by IR, NMR spectroscopy, and mass spectrometry methods.

Взаимодействием 2-[3-метил-7-(тиетанил-3)- и 2-[3-метил-7-(1,1-диоксотиетанил-3)-1-этилксантинил-8-тио]уксусных кислот с аминами (диэтиламином, моноэтаноламином, диэтаноламином, трисамином, пиперидином, циклогексиламином, бензиламином) получены соли 2-[3-метил-1-этилксантинил-8-тио]уксусных кислот, содержащие тиетановый и диоксотиетановый цикл, с выходом 42 – 89 %. Структура синтезированных соединений подтверждена данными ИК- и ЯМР-спектроскопии. Выявлено, что синтезированные соединения проявляют антиагрегационную активность.

In the present study, an elevated temperature homogeneous liquid extraction coupled with ionic liquid‑based dispersive liquid–liquid microextraction was developed to extract five carbamate pesticides (pirimicarb, carbaryl, methiocarb, aldicarb, and carbofuran) from packed fruit juice samples. The method consisted of a two-step procedure in which cyclohexylamine was used in order to extract the target analytes. In the first step, the analytes were extracted from a sample solution thermostated at elevated temperature (80 °C) into a water-immiscible organic solvent (cyclohexylamine). In the second step, the separated organic phase was mixed with 1-butyl-3-methylimidazolium chloride (as the solvent for extraction) and the mixture was spread into deionized water. In this step, cyclohexylamine controlled the solubility of 1-butyl-3-methylimidazolium chloride in the aqueous phase and acted as a dispersive solvent and a phase separation agent, simultaneously. After centrifugation, we removed all the gathered organic phases and analyzed them by using high-performance liquid chromatography diode-array detector. Figure of merits of the method including the limits of detection and quantification, enrichment factors, extraction recoveries, and relative standard deviations were obtained within ranges 0.4–3.9 and 1.5–13.2 ng mL−1, 147–217, 59–87%, and 3.3–5.5%, respectively, indicating that the method was successful in determining the analytes.

Graphite oxide (GO) exhibits selective sorption of di-butylamine from a mixture of butylamine, di-butylamine and tri-butylamine. The selectivity is attributed to the higher basicity of di-butylamine in comparison to butylamine and tri-butylamine. Reaction of GO with a mixture of hexylamine and cyclohexylamine, two amines of similar basicity but different structures, suggests that in alkylamines, selectivity is predominantly due to the basicity of the amine with structural differences playing almost no role. However, when GO reacts with a mixture of aniline and cyclohexylamine (amines with a large difference in basicity) no selectivity is observed. The π-π interaction between the aromatic amine, aniline, and the aromatic regions of GO causes the sorption of aniline in its non-protonated form as much as cyclohexylamine with a far higher basicity.

The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine. In this work, dispersed Nb oxide supported on SBA-15 catalysts are disclosed to efficiently catalyze the selective oxidation of cyclohexylamine with high conversion (>75%) and selectivity (>84%) to cyclohexanone oxime by O2 without any addition of solvent (TOF = 469.8 h−1, based on the molar amount of Nb sites). The role of the active-site structure identity in dictating the site-specific catalytic activities is probed with the help of different reaction and control conditions and multiple spectroscopy methods. Complementary to the experimental results, further poisoning tests (with KSCN or dehydroxylation reagents) and DFT computational studies clearly unveil that the surface exposed active centers toward activation of the reactants are quite different: the surface –OH groups can catch the NH2 group from cyclohexylamine by forming a hydrogen bond and lead to a more facile cyclohexylamine oxidation to desired products, while the monomeric or oligomeric Nb sites with a highly distorted structure play a key role in the dissociation of O2 molecules beneficial for insertion of active oxygen species into cyclohexylamine. These catalysts exhibit not only satisfactory recyclability for cyclohexylamine oxidation but also efficiently catalyze the aerobic oxidation of a wide range of amines under solvent-free conditions.

A comparative model for the chemisorption of CO2 was explored via three representative reaction pathways: carboxylation of cyclohexanone, carbonation of cyclohexanol, and carbamation of cyclohexylamine. The model substrates were activated using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, an amidine superbase). For each of these reactions, the formation of the corresponding CO2 adducts was confirmed by 13C nuclear magnetic resonance and Fourier-transform infrared spectroscopy measurements. It was demonstrated that CO2 fixation occurred through either an enol-CO2 adduct (i.e. carboxylation), proton shuttling process (i.e. carbonation), or self-activation mechanism (i.e. carbamation). Volumetric adsorption measurements indicated that cyclohexanol was superior in its uptake capacity (11.7 mmol CO2 g−1 sorbent) in comparison to cyclohexylamine (9.3 mmol CO2 g−1 sorbent) or cyclohexanone (8.5 mmol CO2 g−1 sorbent). As supported by density functional theory calculations, this trend was expected given the fact that the carbonation reaction proceeded through a more thermodynamically favorable reaction process.

The data on adsorbability of oleamides and hexylamine, cyclohexylamine, morpholine, piperidine, and piperazine salts of oleic acid are systematized in this study. The protective mechanism of these compounds is studied in order to reveal a correlation between the inhibiting ability and the calculated parameters of the molecules. A procedure for measuring the Volta potential difference using a Poverkhnost-II high-sensitivity digital electrometer under the conditions when water- and hydrocarbon-soluble corrosion inhibitors interact with the steel and copper surface is elaborated. It has been proven that a high-efficiency corrosion inhibitor can be designed based on the data on its donor properties and adsorbability.

Modified UNIFAC (Dortmund) parameters for the interactions of the amino group at cycloaliphatic hydrocarbon with the hydroxyl group or the methanol group were determined by means of literature and our own experimental data. The vapor–liquid equilibria of the three binary systems cyclohexylamine + 2-butanol, cyclohexylamine + 2-methyl-2-butanol, and cyclohexylamine + 1-hexanol were measured isothermally with the dynamic method. The predictions of phase equilibrium data using the new parameter set for the amino group at cycloaliphatic hydrocarbon are compared to the predictions using the amino group at aliphatic hydrocarbon. The improvement of the description of experimental data is shown for binary and ternary systems.

Nitrogen-doped bamboo-like carbon nanotube (N-BCNT) coating was synthesized onto the surface of zeolite beads by using Catalytic Chemical Vapour Deposition (CCVD) method to develop a “support on support” (SoS) system. These complex structured materials were used as supports during the preparation of hydrogenation catalysts. Rhodium, palladium and platinum nanoparticles were deposited homogeneously onto the surface of the N-BCNTs of the SoS (final metal content 2 wt%). The catalytic activity of these samples was compared in the hydrogenation of nitrobenzene. The Pt/N-BCNT-zeolite sample was the most active (182 mol nitrobenzene after 30 min). The activity of the other two catalysts at 20 bar was well below this value, 99.5 mol after 60 min and 96 mol after 120 min for Pd and Rh, respectively. The aniline selectivity was different for the three catalysts and they facilitate the formation of various by-products (e.g. N-methylaniline, cyclohexylamine). The usage of the Pd and Pt/N-BCNT-zeolite catalysts are more convenient, as only one main by-product was formed. It was confirmed that the zeolite supported N-BCNTs are efficient catalyst supports in hydrogenation processes. Furthermore, by using this special SoS structure to support the catalytic metals the applicability is widened and the catalyst removal is easier.

In this work, we investigated the host ability of TETROL [(+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] in the presence of two guest series, namely saturated cyclohexanone, cyclohexanol and cyclohexylamine on the one hand, and aromatic/saturated combinations of aniline, cyclohexylamine, phenol and cyclohexanol on the other. TETROL formed complexes with all of these guests in single solvent experiments, while mixed complexes were obtained when the host was recrystallized from guest mixtures. However, most notably, TETROL showed enhanced selectivities for the amino-containing cyclic organic compounds compared with the ketone and alcohol, results of which allude to the potential of purifying various combinations of such compounds through host‒guest chemistry. We conducted single crystal X-ray diffraction experiments in order to reveal the underlying reasons for the selectivity displayed by TETROL for these amines.

The present work is aiming to utilize Re based catalysts for hydrodenitrogenation (HDN) of cyclohexylamine over SBA-15 supported catalyst under optimized conditions. Siliceous SBA-15 was synthesized by hydrothermal method and used as a support for Re catalysts with different Re loadings (1, 3, 5 and 7 wt%). The supported catalysts were characterized by various physico-chemical techniques like XRD, N2-sorption studies, UV-DRS, FE-SEM, HR-TEM, NH3-TPD, Raman spectroscopy and XPS (sulfided catalyst). The oxide catalysts were presulfided before the hydrodenitrogenation reaction using ditertiary butyl polysulfide (DBPS) as sulfiding agent and hydrogen. The catalytic activity of the sulfided catalysts was tested for HDN of cyclohexylamine. A high HDN activity was observed on 5 wt% Re loaded SBA-15 catalyst. The catalytic activity was correlated with characterization results.

A medicinal chemistry program to develop potent and selective LABA compounds required the synthesis of both carbon-14 and stable-isotope labelled materials. Carbon-14 labelled AZD7307 was successfully synthesised in 6 steps from [14C]chloroacetyl chloride in an overall radiochemical yield of 10%. In addition, the synthetic route of a stable labelled isotopomer of AZD7307 is also described and synthesised in four linear steps from [13C6]cyclohexylamine hydrochloride in an overall yield of 12%.

An atom-economic and moderate approach for highly selective one-step catalytic amination of cyclohexene to cyclohexylamine using HZSM-5 with a Si/Al ratio of 38 has been successfully developed in this work. Results showed that 4.3% cyclohexene conversion with 100% selectivity to cyclohexylamine was achieved under optimal reaction conditions. The acid strength of the catalyst played an extraordinarily important role in the present amination reaction. The possible catalytic amination mechanism of cyclohexene with NH3 using HZSM-5 has also been suggested. This approach is a promising process for the preparation of cyclohexylamine from one-step amination of cyclohexene employing commercialized HZSM-5 as an effective and regenerable catalyst under relatively mild conditions.

The influence of domestic nitrogen-containing corrosion inhibitors of the VNKh-L type on corrosion regularities of a zinc coating on steel in neutral media is investigated. This work is aimed at studying the surface structure of a corroding zinc coating, as well as the influence of conditions simulating the degradation of inhibitors during real operation on their protective properties. Mechanical activation in a ball planetary mill is used to simulate the deformation and thermal operational conditions of inhibitors. Corrosion of a zinc coating on steel is carried out in a sulfate–chloride medium simulating atmospheric corrosion and in a borate buffer solution. The concentration of inhibitors in the corrosion media was 0.2 wt %. The morphology of a corroded surface of a zinc coating is studied using a Philips SEM-515 scanning electron microscope (at an accelerating voltage of 10 kV) with an X-ray microprobe. Studies of the corrosion rate of zinc coating on St 08 are carried out by the indirect measurement of corrosion resistance with the help of a MONIKOR-1 corrosion meter. A borate buffer solution (Na2B4O7 + H3BO3, pH 6.6) and a solution simulating atmospheric corrosion (NaCl + Na2SO4, pH 6.0) are used as corrosion media. The corrosion rate of samples in corrosive media without an inhibitor is accepted 1. The exposure time of each sample in corrosive media is 3 h. The chemical composition of corrosion products is studied by the mirror reflection in the IR range. The IR spectra of the metal plate surface are recorded using an FSM-1202 IR Fourier spectrometer in a wavelength range of 450–4000 cm–1 with a resolution of 2 cm–1 and an accumulation of 100 scans. To record the reflection spectra, a mirror-reflection attachment with a 10° angle of incidence is used. The corrosion rate of zinc coating in sulfate–chloride and solvent media in the presence of inhibitors based on benzotriazole and cyclohexylamine is practically not decreased when compared with the corrosion rate in the same media without inhibitors. The addition of both initial and mechanically activated inhibitors based on morpholine and benzotriazole to the corrosion medium decreases the corrosion rate of iron when compared with the corrosion in the same media without inhibitors. The pitting corrosion of a zinc coating is observed in the presence of initial and mechanically activated inhibitors of both types in studied corrosion media. Herewith, the pitting depth is smaller than the zinc-coating thickness under these conditions.

Heat-induced homogeneous liquid-liquid microextraction method (HIH-LLME) has been proposed for separation/enrichment of trace levels of erythrosine in drug, cosmetic and food samples prior to its UV-Vis spectrophotometric determination. Cyclohexylamine was utilised as extraction phase to produce two different phases. It dissolves in water at low temperatures and decreases its solubility in water when heated. Thus, the heated sample forms a two-phase system in NaCl medium and erythrosine was extracted into cyclohexylamine phase. Analytical parameters such as volume of cyclohexylamine, amount of NaCl, pH, effect of matrix ions and temperature have been optimised. Optimum pH has been set at pH 5. The proposed (HIH-LLME) method exhibits a limit of detection (LOD) of 0.006 mu g mL(-1) and a limit of quantification (LOQ) of 0.021 mu g mL(-1). A pre-concentration factor was obtained as 37.5 and the relative standard deviation was 2.9%. This method is environmentally sensitive due to the usage of very little organic solvent and at the same time, it is simple and fast and it has a low cost and short extraction period. Cyclohexylamine solvent showed a high affinity and good accessibility for erythrosine.

Hexamethyleneimine (HMI) is used as the structure-directing agent (SDA) in the conventional synthesis method of MCM-49 zeolite. Cyclohexanine (CA) is less toxic and cheaper than HMI. Hence, in this paper, MCM-49 zeolite was successfully synthesized by using CA as a sole SDA with the aid of seeds. Both the seed and template CA are indispensable for the synthesis of MCM-49 zeolite. The optimum synthesis conditions were obtained. The range of the SiO2/Al2O3 ratio of the initial gel was broadened to 70. The synthesis of MCM-49 followed the liquid-phase crystallization mechanism. The MCM-49 zeolites synthesized by using CA and conventional template hexamethyleneimine (HMI) exhibit similar intrinsic properties, such as morphology, acidity, BET surface area, SiO2/Al2O3, and so on. The MCM-49(CA) exhibite good catalytic activity and product distribution in alkylation of benzene with methanol.

A new sample preparation method, cyclohexylamine-based heat-induced homogeneous liquid–liquid microextraction, has been developed for the extraction and preconcentration of Cd(II) and Zn(II) ions in edible oils followed by flame atomic absorption spectrometry determination. First, the analytes are extracted into an acidic solution (a balanced mixture of HNO3 and HCl). Second, they are preconcentrated via the microextraction method. Accordingly, cyclohexylamine (as a complexing agent and an extraction solvent) is added at µL-level into the obtained solution containing the analytes to form a homogeneous solution followed by the addition of sodium chloride. After manual shaking, the obtained solution is placed in a water bath thermostated at 60 °C. A cloudy solution because of the decrease in cyclohexylamine solubility in water at high temperature is formed. After centrifuging fine droplets of cyclohexylamine containing Cd(II) and Zn(II)—cyclohexylamine complexes are collected on the top of the aqueous phase. The preconcentrated analytes in the upper phase by use of flame atomic absorption spectrometry are analyzed and determined. Several variables possibly affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, the calibration curves were linear in the ranges of 10–300 and 2.5–200 µg kg− 1 for Cd(II) and Zn(II), respectively. Repeatability of the proposed method, expressed as relative standard deviation, was obtained 2.4 and 1.7% for Cd (II) and Zn(II), respectively. Moreover, the detection limits of the selected analytes were obtained 3.8 and 0.6 µg kg− 1 for Cd(II) and Zn(II), respectively.

The kinetics of the reaction of 2,4-dinitrofluorobenzene with cyclohexylamine were studied at different concentrations in toluene and toluene-alkanol mixtures. The reaction was not base-catalysed in toluene. Addition of small amounts of hydrogen-bond donor solvent, alkanol (ranging from methanol to hexanol) to the toluene medium of the reactions produced a different effect in comparison to uncatalysed reactions — slight increase in rate of reaction. The results are rationalized in terms of the effect of amine-solvent interaction on the nucleophilicity of the amine in addition to some other factors operating through cyclic transition states leading to products. It is also attributed to the peculiar nature of fluoride ion as a leaving group.

An efficient method for the synthesis of 1-isopropyl-4-isothiocyanato-4-methylcyclohex-1-ene has been developed with p-menth-3-en-1-amine as raw material. Next, a number of p-menth-3-en-1-amine thiourea derivatives (4a–f) have been obtained from the reactions between 1-isopropyl-4-isothiocyanato-4-methylcyclohex-1-ene and cyclohexylamine or the reactions between p-menth-3-en-1-amine and different isothiocyanates. Then, the herbicidal activities of these compounds were evaluated. The result indicated that some of these newly synthesised compounds displayed remarkable herbicidal activities against annual ryegrass. In addition, the derivative containing cyclohexane ring (4a) displayed much higher herbicidal activity against annual ryegrass than the derivatives containing benzene ring.

International audience; Cyclohexylammonium perchlorate (C6H14N)ClO4 have been achieved from the mixture of perchloric acid with an ethanol solution containing cyclohexylamine by slow evaporation technique. The structure of this compound has been determined by single crystal X-ray diffraction method. This compound crystallizes in monoclinic P21/c space group with the lattice parameters a = 11.1501(19) Å, b = 8.4987(15) Å, c = 9.9517(16) Å, β = 104.166(6) °, Z = 4 and V = 914.4(3) Å3. The FT-IR was used to identify the different vibrational assignments present in the compound. The optical properties were analyzed by UV–Vis spectral analysis. The intermolecular interactions in the crystal structure were examined via topological Atom-in-Molecules (AIM), Natural Bond Orbital (NBO) and Hirshfeld surface (HS) analyses. Reduced density gradient (RDG) was used to study non-covalent interactions. HOMO-LUMO orbital energies were studied by using DFT calculations at B3LYP/6-311++G(d,p) level of theory.

A combined approach to paint was used to increase the effectiveness of anti-corrosion protection was used. In particular, passive insulating coating materials was modified with active additives. A water-soluble anodic inhibitor of atmospheric corrosion was encapsulated in a phosphate conversion coating NOTECH. As a result, the corrosion under a layer of paint primer was suppressed. It is important that phosphating does not create a layer like paint. So, such an approach is universal and compatible with most known types of paint coatings and can be combined with temporary protection (preservation). The second paint layer of the coating contained a water-oil-soluble corrosion inhibitor of the group “M”, namely: N-M-1. It is adduct of natural fat vegetable acids and cyclohexylamine. The data of corrosion tests and polarization curves are presented, which confirm the high protective properties of the proposed binary inhibitory anti-rust paint.

Background - Para-nitrophenyl phosphate, the common substrate for alkaline phosphatase (AP), is available as a cyclohexylamine salt. Here, we report that cyclohexylamine is a non-competitive inhibitor of APs. Methods - Cyclohexylamine inhibited four different APs. Co-crystallization with the cold-active Vibrio AP (VAP) was performed and the structure solved. Results - Inhibition of VAP fitted a non-competitive kinetic model (Km unchanged, Vmax reduced) with IC50 45.3 mM at the pH optimum 9.8, not sensitive to 0.5 M NaCl, and IC50 27.9 mM at pH 8.0, where the addition of 0.5 M NaCl altered the inhibition to the level observed at pH 9.8. APs from E. coli and calf intestines were less sensitive to cyclohexylamine, whereas an Antarctic bacterial AP was similar to VAP in this respect. X-ray crystallography at 2.3 Å showed two binding sites, one in the active site channel and another at the surface close to dimer interface. Antarctic bacterial AP and VAP have Trp274 in common in their active-sites, that takes part in binding cyclohexylamine. VAP variants W274A, W274K, and W274H gave IC50 values of 179 mM, 188 mM and 187 mM, respectively, at pH 9.8. Conclusions - The binding of cyclohexylamine in locations at the dimeric interface and/or in the active site of APs may delay product release or reduce the rate of catalytic step(s) involving conformational changes and intersubunit communications. General significance - Cyclohexylamine is a common chemical in industries and used as a counterion in substrates for alkaline phosphatase, a clinically important and common enzyme in the biosphere.

Made available in DSpace on 2021-06-25T10:36:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01. Added 1 bitstream(s) on 2021-07-15T15:04:44Z : No. of bitstreams: 1 S0103-50532020001002038.pdf: 1452643 bytes, checksum: 5c848da2aacc2cab5a4c989049e3d2ef (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A new methodology using gas-diffusion microextraction (GDME) was developed for the analysis of volatile corrosion inhibitors (VCIs). The evaluation of the inhibition efficiency and corrosion rate (ν) was performed by NaCl deliquescence tests and correlated with measurements of polarization resistance (Rp) obtained from electrochemical impedance spectroscopy (EIS) analysis and with the pH resulting from the atmosphere of the inhibitor (pHGDME). The correlation obtained between ν and pHGDME indicates that the higher the value of pHGDME the lower the corrosion rate. The Raman spectra of steel was used to monitor in situ adsorption of VCI and the surface modifications caused by the inhibitors. The scanning electron microscopy (SEM) images corroborate the data of ν, both indicating that the cyclohexylamine vapor showed the best corrosion resistance performance. Departamento de Físico-Química Instituto de Química Universidade Estadual Paulista (Unesp) Departamento de Química Fundamental Instituto de Química Universidade de São Paulo (USP) REQUIMTE/LAQV Departamento de Química e Bioquímica Faculdade de Ciências da Universidade do Porto Departamento de Química Analítica Instituto de Química Universidade Estadual Paulista (Unesp) Departamento de Físico-Química Instituto de Química Universidade Estadual Paulista (Unesp) Departamento de Química Analítica Instituto de Química Universidade Estadual Paulista (Unesp) FAPESP: 2018/14425-7