Regeneration of 2-amino-2-methyl-1-propanol used for carbon dioxide absorption

To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regeneration runs descended from 98.3% to 94.0%. A number of heat-stable salts （HSS） could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine （MEA）, diethanolamine （DEA）, diethylenetriamine （DETA）, and N-methyldiethanolamine （MDEA）.

Controlled Self-assembly of Two Coordination Polymers via subtly Varying Bis(2-methyl imidazole) Ligands:from 3-Connected(6,3) Net to 4-Connected sql Net

Two coordination polymers constructed from 3,4-thiophenedicarboxylic acid and bis（2-methyl imidazole） ligands, namely, {[Cd2（tdc）2（bip）2]·7H20}n （1） and [Cd（tdc）（bib）]n （2） （Hgtdc = 3,4-thiophenedicarboxylic acid, bip = 1,3-bis-（imidazol-2-methyl）propane and bib = 1,4-bis（imidazol-2-methyl）butane）, have been synthesized and structurally characterized by single-crystal X-ray diffraction. Structural analyses reveal that 1 exhibits a two-dimensional （2D） layered network with 3-connected （6,3） topology, which is further connected into a three- dimensional （3D） supramolecular structure by intermolecular hydrogen bonds. However, 2 features a 2D network which can be rationalized as a 4-connected sql net. The results indicate the subtle difference of auxiliary bis（imidazol-2-methyl） ligands may lead to diverse architectures. Moreover, they exhibit luminescence emission in the solid state at room temperature.

The First Two-dimensional Supramolecular Network Constructed by Na(Ⅰ) with 2-Methylimidazole-4,5-dicarboxylate Building Blocks

The title complex [Na（H2MIA-）（H2O）]（1,H3MIA = 2-methyl-1H-imidazole-4,5-dicarboxylic acid） has been synthesized by hydrothermal synthesis and structurally characterized by X-ray crystallography.Compound 1 crystallizes in orthorhombic,space group ibam with a = 14.4737（19）,b = 17.553（2）,c = 6.5285（9）,V = 1658.6（4） 3,C6H7N2NaO5,Mr = 210.12,Z = 8,Dc = 1.675 g/cm3,F（000） = 864,μ = 0.188 mm-1,λ（MoKα） = 0.071073 ,R = 0.0383 and wR = 0.0987 for 1046 observed reflections（I 2σ（I））.In the structure of 1,each coordination water coordinates with two Na（I） ions at the same time and links the neighboring Na（I） ions to form a one-dimensional Na（I）-water chain.Each H2MIA-ligand links the neighboring Na（I） of Na（I）-water chain to form a novel two-dimensional supramolecular network.The 2-D network is stabilized by O-H…N hydrogen bonds and π-π interaction.The 2D network is further linked via O-H…O hydrogen bonds to yield a three-dimensional framework.

Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system(water + 1,6-diaminohexane + 2-methyl-1-propanol) and(water +1,6-diaminohexane + 3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient(D) and selectivity(S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid(NRTL) and universal quasi-chemical(UNIQUAC) models.The percent-root-mean-square deviation(RMSD) values for NRTL and UNIQUAC models were less than 0.15,which indicated that the experimental data have been sufficiently correlated.

Theoretical Study on the Reaction Mechanism of o-Aminophenol, Acetic Acid and Phosphorus Oxytrichloride One-pot to Form 2-Methyl Benzoxazole

The reaction mechanism of o-aminophenol, acetic acid and phosphorus oxytrichloride in one-pot to form 2-methyl benzoxazole was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the GGA/PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Two possible reaction pathways were investigated in this study. The result indicates that the reaction Re→TS1→IM1→TSA2→IMA2→TSA3→IMA3→TSA4→IMA4→TSA5→P2 is the main pathway, the activation energy of which is the lowest. Re→TS1→IM1 is the rate-limiting step, with the activation energy being 221.54 kJ·mol^(-1) and the reaction heat being 10.06 kJ·mol^(-1). The dominant product predicted theoretically is in agreement with the experiment results.

Interaction of N-(2-Methyl Thio Phenyl)-2-Hydroxy-1-Naphthaldimine with Tin Dioxide Nanoparticles: A Spectroscopic Approach

The interaction of N-(2-methyl thiophenyl)-2-hydroxy-1-naphthaldimine (NMTHN) with tin dioxide nanoparticles (SnO2 NPs) has been investigated by spectroscopic tools such as absorption and fluorescence spectroscopy. Absorption spectroscopy reveals the formation of ground state complex. Fluorescence spectroscopy has been used to study the signatures of fluorescence quenching. SnO2 NPs are found to quench the intrinsic fluorescence of NMTHN via static and dynamic quenching. The deviation from linearity in the Stern-Volmer plot has been observed.

Electron Transfer Reaction Between Desoxyadenosine and Triplet 2-Methyl-1,4-naphthaquinone:A Laser Photolysis Study

Introduction Electron transfer oxidation of DNA by triplet artificial photonuclease reveals a bright prospect of its application in biology and medicine. Both molecular orbital calculation and laser experiments have indicated that the homo guanine sequence should be the final localization site of photoexcited hole via long range migration within DNA. However, the direct observation of the produced ion pairs of biomolecules especially the stabilized radical cation DNA or its components is hampered by the overwhelming transient absorption of protonated radical anion of photosensitizers, such as 2-methyl-1,4-naphthaguinonel （MQ）.

XRD Pattern of Liquid Crystal Monomer Acrylate That Conjugated with Cholesterol and p-Hydroxyphenyl-2-Methyl Butanoic

It was successfully synthesized liquid crystal monomer acrylate that conjugated with two mesogens were cholesterol and p-hydroxyphenyl-2-methyl Butanoat which called MA （monomer cholesteryl acrylate） and monomer （S）-（＋）-4-（2-Methyl butanoat-l-butyloxy） phenyl 4-[1-（propenoyloxy） butyloxy] benzoate （MB）. Two monomers were characterized by DSC （differential scanning calorimetry）, POM （polarization optical microscopy） and XRD （X-ray diffraction）. Mesophase temperatures of MA and MB are 81.28 ~C and 54.36~C, respectively. Textures analysis by POM shows that MA was oily streak and MB was schlieren. XRD pattern shows the strongest three peaks of MA at room temperature which are （20, deg）： 2.7153, 5.2992 and 18.8500. The Strongest three peaks of MB at room temperature are （20, deg）： 9.1726, 9.7707 and 12.5389. XRD pattern of MA and MB at mesophase and above mesophase temperature that each peaks disappear.

Synthesis and Characterization of the Terpolymer of Itaconic Acid with Acrylamide and 2-Acrylamido-2-methylpropanesulfonic Acid

The terpolymer of itaconic acid, acrylamide and 2-acrylamido-2-methyl-1-propane sulfonic acid was synthesized through the free-radical polymerization. The IR spectra confirmed that there was no olefinic band, while the TGA results revealed that the terpolymer was of high thermal stability.

Synthesis, Crystal Structure and Quantum Chemistry of Tris[(2-methyl- 2-phenyl)propyl](2,4-dinitro-phenolato)tin

The tris[（2-methyl-2-phenyl）propyl]（2,4-dinitro-phenolato）tin was synthesized by the reaction of bis[tri（2-methyl-2-phenyl）propyltin] oxide with 2,4-dinitrophenol. The compound was characterized by IR, 1H NMR spectra and elemental analysis. The crystal structure has been determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 0.9649（0）, b = 1.0087（8）, c = 3.4867（4） nm, β = 90.965（7） , Z = 4, V = 3.3933（7） nm3, Dc = 1.369 Mg·m-3, （MoKa） = 0.796 mm-1, F（000） = 1440, R = 0.0345 and wR = 0.0821. The tin atom has a distorted tetrahedral geometry. The 2D network structure of the complex is formed by hydrogen bonds and π-π effects. The stabilities, orbital energies and composition characteristics of some frontier molecular orbitals of the complexes have been investigated with the aid of G98W software.

COPOLYMERS OF 2-ACRYLAMIDO-2-METHYL-1-PROPANESULFONIC ACID/MALEIC ACID:SYNTHESIS,CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY

2-Acrylamido-2-methyl-1-propanesulfonic acid （AMPS）, and maleic acid （MA） copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide （Bz2O2） as an initiator at 70℃. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis （content of N for AMPS-units）. Monomer reactivity ratios for AMPS （M1）-MA （M2） pair were determined by the application of conventional linearization methods such as Fineman-Ross （F-R）, Kelen-Tudos（KT） and Extended Kelen-Tudos （EKT） and a nonlinear error invariable model method using a computer program RREVM. The characterizations were done by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC） thermal gravimetry analysis （TGA）, and and X-ray diffraction. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.

Synthesis and Crystal Structure of an Adipate-bridged Dinuclear Cadmium(Ⅱ)Polymer with 2-Methylpyrazino[2,3-f][1,10]-phenanthroline(mpphen)Terminal Ligands

A metal-organic coordination polymer, [Cd（C15H10N4）（C6H8O4）]2n （1, C15H10N4： 2-methyl-pyrazino-[2,3-f][1,10]-phenanthroline （mpphen）, C6H8O4： adipate）, was synthesized via hydrothermal synthesis. The polymer was characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. X-ray diffraction shows that 1 is a cadmium polymer constructed by adipate-bridged dmuclear clusters, and each adipate connects two clusters to form a two-dimen- sional planar structure. Crystal data for 1： monoclinic, space group C2/c, a = 22.403（9）, b = 16.039（6）, c = 13.808（6） A, β= 125.262（6）°, V = 4051（3） A3, Mr = 502.79, Dc = 1.649 g/eraa, μ（MoKa） = 1.114 mm^-1, F（000） = 2016, Z = 8, the final R = 0.0509 and wR = 0.1054 for 1509 observed reflections （I 〉 2σ（I））.

Syntheses, Characterization and Biological Activity of Coordination Compounds of 3-Hydroxy-2-methyl-4<i>H</i>-pyran-4-one and Its Mixed Ligand Complexes with 1,2-Diaminocyclohexane

Coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one with iron(III), cobat(III) and chromium(III) were synthesized with M:L (1:2). Mixed ligand coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one and 1,2-diaminocyclohexane using the same metal ions were also synthesized M:L1:L2 (1:1:1) where L1 is 3-hydroxy-2-methyl-4H-pyran-4-one and L2 is 1,2-diaminocyclohexane. The coordination compounds obtained were characterized using electronic and infrared spectral analyses, magnetic susceptibility and percentage metal analysis. They were also evaluated for their cytotoxic and antioxidant activities. The result obtained suggested that octahedral geometry was obtained for all the compounds, as a result of additional two molecules of the solvent coordinated to the metal ions. Both the primary and secondary ligands coordinated in a bidentate fashion. The synthesized compounds exhibited moderate cytotoxicity, although none was as active as the standard. The cobalt(III) mixed ligand complex elicited the highest activity. The synthesized compounds all exhibited good to moderate antioxidant activity.

Swelling Properties of New Hydrogels Based on the Dimethyl Amino Ethyl Acrylate Methyl Chloride Quaternary Salt with Acrylic Acid and 2-Methylene Butane-1,4-Dioic Acid Monomers in Aqueous Solutions

Hydrogels of dimethylaminoethyl acrylate methyl chloride quaternary salt (Q9) have been synthesized with different monomer ratio by copolymerization of this poorly studied monomer either with acrylic acid or with 2-methylene bu-tane-1,4-dioic acid. Hydrogel swelling was measured as a function of the composition of the hydrogel and of the crosslinking agent ratio. High values of swelling have been obtained at very high crosslinking values (【14 wt %) and the equilibrium swelling was reached at very low time (less than 15 minutes). The swelling isotherms consisted of a steep initial portion and then levelled off as asymptotically to the equilibrium swelling limit. The experimental data suggest clearly that the swelling process obeys second-order kinetics. According to this, the kinetics rate constant and the equilibrium water content were determined at different comonomer composition and crosslinker concentration. The calculated kinetic constants ranged from 0.48 to 3.76 &#215;10-2 min-1 for poly (acrylic acid-co-Q9) hydrogels and from 0.68 to 4.0 &#215;10-2 min-1 for poly (2-methylene butane-1,4-dioic acid-co-Q9) hydrogels depending on the hydrogels composition. The diffusion process was evaluated for each hydrogel showing a non-Fickian type diffusion. In all cases was observed a considerable increase in diffusion coefficient as Q9 content increases.

Biodegradation of 2-methylisoborneol by bacteria enriched from biological activated carbon

One of the most common taste and odour compounds （TOCs） in drinking water is 2-methylisobor- neol （2-MIB） which cannot be readily removed by conventional water treatments. Four bacterial strains for degrading 2-MIB were isolated from the surface of a biological activated carbon filter, and were characterized as Micrococcus spp., Flavobacterium spp., Brevibacterium spp. and Pseudomonas spp. based on 16S rRNA analysis. The removal efficiencies of 2-MIB with initial concentra- tions of 515 ng.L i were 98.4%, 96.3%, 95.0%, and 92.8% for Micrococcus spp., Flavobacterium spp., Brevibacter- ium spp. and Pseudomonas spp., respectively. These removal efficiencies were slightly higher than those with initial concentration at 4.2 mg. L~ （86.1%, 84.4%, 86.7% and 86.0%, respectively）. The kinetic model showed that biodegradation of 2-MIB at an initial dose of 4.2 mg. L1 was a pseudo-first-order reaction, with rate constants of 0.287, 0.277, 0.281, and 0.294d-1, respectively. These degraders decomposed 2-MIB to form 2-methylenebor- nane and 2-methyl-2-bornane as the products.

Treatment of taste and odor causing compounds 2-methyl isoborneol and geosmin in drinking water:A critical review

Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds - 2-methyl isobomeol （MIB） and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed alongwith the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a full- scale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for removal of M1B/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be effective in treatment of these two compounds. Although some of these technologies are more effective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and effectiveness of the treatment system.

Cloning and analysis of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase genes HsHDR1 and HsHDR2 in Huperzia serrate

We cloned and analyzed the two genes of the 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase(HDR) gene family from Huperzia serrate.The two transcripts coding HDR,named Hs HDR1 and Hs HDR2,were discovered in the transcriptome dataset of H.serrate and were cloned by reverse transcription-polymerase chain reaction(RT-PCR).The physicochemical properties,protein domains,protein secondary structure,and 3D structure of the putative Hs HDR1 and Hs HDR2 proteins were analyzed.The full-length c DNA of the Hs HDR1 gene contained 1431 bp encoding a putative protein with 476 amino acids,whereas the Hs HDR2 gene contained 1428 bp encoding a putative protein of 475 amino acids.These two proteins contained the conserved domain of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase(PF02401),but without the transmembrane region and signal peptide.The most abundant expression of Hs HDR1 and Hs HDR2 was detected in H.serrate roots,followed by the stems and leaves.Our results provide a foundation for exploring the function of Hs HDR1 and Hs HDR2 in terpenoid and sterol biosynthesis in Huperziaceae plants.

Synthesis and Antimicrobial Activity of 2-Methyl-5-nitroaniline Derivatives： A Structure-Activity Relationship Study

A series of 2-methyl-5-nitroaniline derivatives, 5a--Sk and 6a--6f, were synthesized in order to determine their in vitro antimicrobial activity. The chemical structures of the synthesized compounds were confirmed by elemental analyses, UV-visible, FT-IR, 1H NMR and 13C NMR spectral studies. The structure-activity relationships of the synthesized compounds were also discussed. Among the synthesized compounds, 5f, 5d, 6b and 6e showed good antimicrobial activity compared to standard drugs.

FAM 19A 4、PAX 1及miRNA124-2基因启动子区甲基化在宫颈病变早期诊断中的价值

背景与目的:目前有关宫颈病变的DNA甲基化研究较多,但DNA甲基化作为宫颈病变的诊断及分流指标在临床实践中的报道较少。本研究拟探讨FAM19A4、PAX1及miRNA124-2基因启动子区甲基化在宫颈病变进展中早期诊断的价值。方法:收集2020年3月—2022年3月在郑州大学第三附属医院同时行宫颈液基细胞学(thinprep cytologic test,TCT)和HPV检测的患者的宫颈细胞学标本共129例,采用甲基化特异性PCR(methylation-specific PCR,MSP)检测不同宫颈病变中FAM19A4、PAX1及miRNA124-2基因启动子区甲基化改变情况,采用受试者工作特征(receiver operating characteristic,ROC)曲线评估3个基因甲基化改变对宫颈病变的诊断价值。本研究经郑州大学第三附属医院伦理委员会批准(伦理审批编号:2023-135-01)。结果:根据病理学检查结果分为4组:未见上皮内病变或恶性细胞(no intraepithelial lesions or malignant lesions,NILM)组(42例)、低度鳞状上皮内病变(low grade squamous intraepithelial lesion,LSIL)组(28例)、高度鳞状上皮内病变(high grade squamous intraepithelial lesion,HSIL)组(36例)和鳞癌(squamous cervical cancer,SCC)组(23例)。随宫颈病变级别的增加,FAM19A4、PAX1及miRNA124-2基因甲基化检出率逐步增高,差异有统计学意义(P均<0.05)。在HSIL组FAM19A4、PAX1、miRNA124-2甲基化检出率分别为81.2%、80.5%和71.8%,在SCC组3种基因甲基化检出率均高达100.0%;细胞学诊断宫颈癌的ROC曲线下面积(area under curve,AUC)为0.731,诊断灵敏度和特异度分别为65.9%和80.4%;FAM19A4、PAX1及miRNA124-2基因单独诊断HSIL+(HSIL和SCC)时,PAX1甲基化诊断HSIL+的效能最高,AUC为0.925,灵敏度为92.8%,特异度为87.3%;两两联合诊断时,FAM19A4与PAX1联合诊断HSIL+的AUC为0.930,灵敏度为95.7%,特异度为87.1%;FAM19A4与miRNA124-2联合诊断HSIL+,AUC为0.895,灵敏度为97.6%,特异度为85.7%;PAX1联合miRNA124-2诊断HSIL+,AUC为0.928,灵敏度为95.7%,特异度为89.1%;PAX1、FAM19A4及miRNA124-2基因甲基化联合诊断HSIL+,AUC为0.928,灵敏度为100.0%,特异度为81.8%。结论:FAM19A4、PAX1及miRNA124-2基因启动子区甲基化诊断宫颈病变具有较高的灵敏度和特异度,有潜力成为宫颈病变早期诊断的新指标。