Dimethyl Methyl Research Articles

Discovering Novel Organophosphorus Compounds in Wastewater Treatment Plant Effluents through Suspect Screening and Nontarget Analysis.

Limited knowledge on the structure of emerging organophosphorus compounds (OPCs) hampers our comprehensive understanding of their environmental occurrence and potential risks. Through suspect and nontarget screening, combining data-dependent acquisition, data-independent acquisition, and parallel reaction monitoring modes, we identified 60 OPCs (17 traditional and 43 emerging compounds) in effluents of 14 wastewater treatment plants (WWTPs) in Beijing and Qinghai, China. These OPCs comprise 26 organophosphate triesters, 17 organophosphate diesters, 6 organophosphonates, 7 organothiophosphate esters, and 4 other OPCs. Notably, 14 suspect OPCs were newly identified in WWTP effluents, and 16 nontarget OPCs were newly discovered in environmental matrices. Specifically, the cyclic phosphonate, (5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl dimethyl phosphonate P-oxide (PMMMPn), consistently appeared in all WWTP effluents, with semiquantitative concentrations ranging from 44.4 to 282 ng/L. Its analogue, di-PMMMPn, presented in 93% of wastewater samples. Compositional differences between the WWTP effluents of two cities were mainly attributed to emerging OPCs. Hazard and ecological risk assessment underscored the substantial contribution of chlorinated organophosphate esters and organothiophosphate esters to overall risks of OPCs in WWTP effluents. This study provides the most comprehensive OPC profiles in WWTP effluents to date, highlighting the need for further research on their occurrence, fate, and risks, particularly for chlorinated OPCs.

Development of the geopolymer-based zeolite from powdery silica fume and its application in methanol to dimethyl ether

A large number of non-biodegradable powdery silica fume waste produced in industry increase the severity of environmental problems due to their potential harmfulness. The synthesis of geopolymers or zeolitic materials using powdery silica fume as silicon source has become an attractive sustainable solution to remedy this crisis. In this paper, a cost-effective porous ferrierite was synthesized by a facile hydrothermal strategy using silica fume-based geopolymer as precursor and applied to methyl dimethyl ether reaction (MTD). The specific surface area of geopolymer increased from 30.5 to 258.4 m2/g of ferrierite, and the methanol conversion rate correspondingly improved from 16.04 % to 78.5 %. Moreover, rare earth (RE) metal ions were introduced to optimize the performance, and the maximum conversions of RE-modified ferrierite were higher than 90 %. The superior catalytic performance of RE-modified ferrierite was related to the synergy of abundant porosity, acidic active sites and metal functions, which could be realized by regulating the crystallization degrees and ion exchange concentrations. Moreover, the abundant active amorphous silica in silica fume is conducive to the preparation of eco-friendly geopolymers and the further development of zeolite materials, realizing the high value-added utilization of solid wastes.

Destruction of dimethyl ether and methyl formate by collisions with He+ (Corrigendum)

Destruction of dimethyl ether and methyl formate by collisions with He⁺ <i>(Corrigendum)</i>

Fireproofing wood using borate and vinyl phosphorus compounds and its water resistant treatment using copolymer of dimethyl vinylphosphonate and methyl methacrylate

Vinyl phosphorus compounds such as poly (vinyl phosphonic acid) (PVPA), poly (dimethyl vinyl phosphonate) (PDMVP) impart high flame retardancy to wood comparable to conventional fireproofing wood by combined use of sodium polyborate (SPB) in contrast to their single use. The differential thermal analysis and thermogravimetry (DTA/TG) suggest a synergy effect between SPB and PVPA. The water resistance of the treated wood is improved by copolymerization of dimethyl vinyl phosphonate (DMVP) with methyl methacrylate (MMA) inside the wood after the impregnation of SPB, and the incombustibility of the wood is mostly maintained after leaching tests. The combustion residues of the wood treated with DMVP and MMA after SPB show high compressive strength, and their SEM images suggest that the strength is due to formed charcoal.

Effects of Dimethyl Anthranilate-Based Repellents on Behavior, Plumage Condition, Egg Quality, and Performance in Laying Hens.

Feather pecking is a behavior that occurs in order to cope with a constrained environment and is a serious problem in the egg production industry. This longitudinal study was conducted under commercial conditions to investigate whether the application of two repellent mixtures, previously suggested as aversive to wild birds, to the plumage of Prelux-R hybrid egg layers is a viable alternative to beak trimming as a solution to discourage feather pecking among laying hens. A total of 180 untrimmed hybrid layers was reared together in a floor pen. At 18 weeks of age they were allocated randomly to three treatments (repellent P, repellent T, control), each consisting of 6 replicated enriched cages with 10 hens in each cage. Hens were evenly sprayed once every 2 weeks for 54 weeks with solution P (dimethyl anthranilate and methyl phenylacetate), solution T (dimethyl anthranilate and geraniol), or distilled water (control). Body weight, plumage condition, behavior, feed intake, and egg quality measurements were taken at five time periods from 26 to 76 weeks of age. Egg production and mortality were recorded daily. The treatments did not affect feather pecking behavior. Hens treated with repellent T tended to perform less cage pecking than the control hens. The use of the repellents did not reduce feather pecking, the plumage was even more significantly damaged in the hens given the repellents compared to the control hens. This suggests the chemicals in the repellents worsened the plumage. No differences in feed intake and daily egg production between treatments were found. Raw and hard-boiled eggs were highly uniform in odor/flavor/taste and no offensive odor absorption related to the chemicals in the repellents was detected. In conclusion, in the present study we did not find any beneficial effect of dimethyl anthranilate-based repellents on feather pecking frequency and plumage/feather condition. Therefore, we do not encourage their use in wider commercial settings.

Synthesis of Hydroxy Aminimide from Unsymmetric Dimethyl Hydrazine Through One Pot Reaction: A New Nanoscale Access for the Reutilization of Unsymmetrical Dimethyl Hydrazine.

In this paper, two new kinds of hydroxy aminimide were nanoscale synthesized utilizing Unsymmetrical dimethyl hydrazine (UDMH) and economical carboxylic acid methyl ester was analyzed through one pot reaction. The reaction conditions were examined and the best reaction temperature was 20 °C with the reaction time of 60 h, achieving a highest yield of 83.21% for the two aminimides. Structures of the final products are characterized by GC-MS, FT-IR and NMR. Then the thermal stability of the aminimide is tested and it is found that the decomposition temperature of one aminimide is 65.20 °C, which is better than any other aminimides used for the latent curing agent of epoxide resin.

Seminal characteristics and sensitivity of Astyanax lacustris (Characiformes: Characidae) sperm to cryoprotective solutions based on dimethylsufoxide and methylglicol

Abstract This study aimed to determine the semen characteristics of Astyanax lacustris after hormonal induction and to evaluate the sensitivity of the species sperm to cryoprotective solutions based on the cryoprotectants dimethyl sulfoxide and methyl glycol. Volume, color, sperm concentration, total motility and aspects of sperm movement were analyzed using “Integrated Semen Analysis System”. Three different extenders were tested: A) glucose 5%+egg yolk 10%, B) BTS®5% and C) glucose 5% and two permeable cryoprotectants: dimethyl sulfoxide (Me2SO) and methyl glycol (MTG). Fresh A. lacustris semen presented total motility of 76.6±11.2%, motility duration of 33.0±2.2s, sperm concentration of 7.22±3.2×109sptz/mL and seminal osmolality of 219±0.03mOsm/kg-1. The toxicity test showed the highest total motility values at the MTG15%+A, Me2SO15%+B and Me2SO10%+C dilutions, and the Me2SO10%+C and Me2SO15%+C dilutions presented the highest values for curvilinear velocity, linear velocity and average velocity. The tested protocol was not effective at maintaining the viability of A. lacustris semen after freezing because no motility was observed in any of the dilutions. However, the Comet Assay demonstrated that cryoprotectant solutions were effective in protecting the genetic material of cells, as DNA damage levels were low, with no difference between control and Me2SO10% + A, dilutions MTG10%+C, Me2SO10%+B and Me2SO15%+B.

Corrigendum to: Production performance of laying hens at peak lay, sulfur compounds in manure, and selected serum profiles: efficacy of Lactobacillus species as probiotics

ContextProbiotics have potential to improve health of laying hens, thus improving the overall quality of eggs. AimsA study was conducted to evaluate the use of probiotics containing Lactobacillus species to improve egg quality and serum biochemistry, and to lower the concentration of sulfur-containing gas compounds from poultry manure. MethodsNinety-six White Leghorn W-36 laying hens (32 weeks old) were randomly assigned to two feeding treatments: Control and Control + Probiotics. A combination of probiotics (Lactobacillus paracasei, L. plantarum and L. rhamnosus totalling 1 × 1012 CFU/kg feed) was provided for 8 weeks. At Weeks 0, 4 and 8, eggs were analysed for weight, shell thickness, albumen height and Haugh unit. Faecal matter was analysed for total sulfur, sulfate-sulfur and 20 reduced sulfur compounds. Blood serum was analysed for amylase, calcium, phosphate, total cholesterol and triglycerides. Key resultsNo significant differences were observed between the two treatments for any of the parameters. Five sulfide gases were detected in manure: hydrogen sulfide (H2S), dimethyl sulfide (CH3)2S, methyl mercaptan (CH3SH), carbonyl sulfide (COS) and carbon disulfide (CS2). Ratios of various detectable gases were computed. Trends for ratios H2S:(CH3)2S, H2S:CS2, and H2S:COS from manure for both treatments were &amp;gt;1, whereas the ratios H2S:CH3SH and (CH3)2S:CH3SH were ConclusionOverall, probiotics did not enhance production, egg quality or the serum profile. ImplicationsPossibly, the concentration of probiotics was too high, limiting bacterial colonisation and beneficial effects.

Synthetic and mechanistic studies in enantioselective allylic substitutions catalysed by palladium complexes of a modular class of axially chiral quinazoline-containing ligands

The application of palladium complexes of a modular series of axially chiral phosphinamine ligands, the Quinazolinaps, to the enantioselective alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate and methyl dimethyl malonate is described. Complete conversions and enantiomeric excesses of up to 91% were obtained. To elucidate the solution structure of these complexes and their dynamic behaviour, 2D COSY and NOESY NMR experiments were carried out. An X-ray crystal structure of a palladacycle derived from 2-phenylQuinazolinap which possesses two Pd3Cl5 units is shown. Computational studies were also undertaken to allow qualitative predictions of diastereomeric ratios. The observed enantioselectivity was then rationalised in terms of combined spectroscopic and theoretical data. The catalytic results obtained are best interpreted by the reaction proceeding with nucleophilic attack on the allyl trans to the phosphorus donor atom of the major diastereomeric intermediate.

Cascade Synthesis of 2-Azafluorene, Azocine, and Azabicyclononane Derivatives by Reaction of Activated Acetylenes with Some β-Amino Ketones

Double Mannich bases obtained from α-indanone and α-tetralone contain a bis-β-amino ketone fragment and are promising intermediate compounds for the synthesis of nitrogen heterocycles via reactions with dimethyl acetylenedicarboxylate and methyl propiolate. The products of these reactions are determined by the activated acetylene structure. The reaction begins with attack of the activated acetylenic compound on the tertiary nitrogen atom of the Mannich base to give 1,3-zwitterionic intermediate. The subsequent domino reaction is driven by neutralization of the charge on the nitrogen atom through formation and/or rupture of several C–C bonds. Intramolecular attack of the negatively charged center of the 1,3-zwitterion derived from the indanone base and dimethyl acetylenedicarboxylate on the carbonyl carbon atom of the indanone fragment is followed by domino process, leading to the formation of dimethyl 2-methyl-1,2-dihydro-9H-indeno[2,1-c]-pyridine-3,4-dicarboxylate. The reaction of the same Mannich base with methyl propiolate involves 1,3-sigma-tropic rearrangement with neutralization of the positive charge on the nitrogen atom in the intermediate structure and negative charge transfer to the carbonyl oxygen atom. Next follows aldolization/crotonization with the second β-amino carbonyl fragment to produce methyl 2′-methyl-1-oxo-1,1′,2′,3,5′,11′-hexahydrospiro-[indene-2,6′-indeno[2,1-c]azocine]-4′-carboxylate. One more reaction direction leading to the formation of linear enamines via intramolecular proton migration from the indan fragment to the C-anionic center in the 1,3-zwitterion with simultaneous elimination of 2-methylideneindan-1-one has been revealed by HPLC/MS analysis of both reaction mixtures. Such enamines, methyl 3-{methyl[(1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)methyl]amino}prop-2-enoate and dimethyl (2Z)-2-{methyl[(1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)-methyl]amino}but-2-enedioate, were isolated in the reactions of activated acetylenic compounds with the Mannich base derived from tetralone. Previously described synthesis of 1-azabicyclo[3.3.1]nonanes from Mannich bases has been reproduced, and detailed analysis of the reaction mixtures has revealed products resulting from elimination of one alkylaryl group from the zwitterionic intermediate. The formation of linear enamines, dimethyl (2Z)-2-[methyl(3-oxo-3-phenylpropyl)amino]but-2-enedioate and dimethyl (2Z)-2-{methyl-[3-oxo-3-(thiophen-2-yl)propyl]amino}but-2-enediate, suggests facile retro-aldol reaction of 3-aroyl-4-aryl-1-methylpiperidin-4-ols as the necessary step. PASS online predicted diverse biological activities of all newly synthesized compounds with a probability of 65–80%.

Addition flame‐retardant effect of nonreactive phosphonate and expandable graphite in rigid polyurethane foams

ABSTRACTA series of flame‐retardant rigid polyurethane foams (RPUFs) containing nonreactive phosphonate (5‐ethyl‐2‐methyl‐1,3,2‐dioxaphosphorinan‐5‐yl) methyl dimethyl phosphonate P‐oxide (EMD) and expandable graphite (EG) were prepared by water blown. The flame‐retardant properties and mechanism of EMD/EG on RPUFs were systematically investigated. The EMD/EG system effectively increased the limiting oxygen index (LOI) value and decreased the values of total heat release (THR), av‐effective heat of combustion (EHC), pk‐heat release rate (HRR), total smoke release (TSR) of RPUFs. The impact values of LOI, THR, and av‐EHC resulted by EMD/EG system are nearly equal to the sum of the impact values by EMD and EG individually in RPUFs, which implies the addition flame‐retardant effect from EMD and EG. EMD alone exerted excellent gas‐phase flame‐retardant effect by releasing PO fragments with quenching effect. The firm residue produced by EMD combined well with the loose and worm‐like expanded graphite from EG further to form compact and expanded char layer, which brought excellent barrier effect and filtration effect to matrix. That's why pk‐HRR and TSR values of RPUF reduced. Depending on the simultaneous actions of EMD/EG system in gas phase and condensed phase during combustion, the flame‐retardant effects from nonreactive phosphonate and EG on RPUFs were added together. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45960.

Silane-bridged diphosphine ligands for nickel-catalyzed ethylene oligomerization

In this study, bis(diphenyl phosphine) dimethyl silane (L1), bis(diphenyl phosphine) methyl dimethyl silane (L2), bis(diphenyl phosphine methyl) dimethyl silane (L3) and their nickel (II) halide complexes, L1/NiBr2 (C1), L2/NiBr2 (C2), L3/NiBr2 (C3), were synthesized and characterized. The X-ray single-crystal analysis of C3 complex showed bidentate coordination on the Ni center. In combination with methylaluminoxane as co-catalyst, these complexes produced catalytic systems for ethylene dimerization to butylene with catalytic activities of up to 3.12 × 106 g mol−1 (cat.) h−1 and selectivities up to 97.6 %. With the fine-tuned ligand backbone, such a PSiP-based catalyst system provides a model for precise understanding of the impact of ligand variations on catalytic performance.

Gas-phase carbonylation of dimethoxymethane to methyl methoxyacetate over the Cs2.5H0.5PW12O40 catalyst

It has been shown that cesium hydrogen phosphotungstate Cs2.5H0.5PW12O40 is a promising catalyst of the gas-phase carbonylation of dimethoxymethane (DMM) to methyl methoxyacetate (MMA). This catalyst provided the MMA selectivity and yield of 54% and 40%, respectively, under mild experimental conditions: T = 110°C, P = 10 bar, and GHSV = 6000 h–1 for DMM/CO/Ar = 4/76/20 mol/mol/mol. The carbonylation of DMM to MMA is accompanied by side reactions of DMM disproportionation into dimethyl ether (DME) and methyl formate (MF), as well as by secondary side reactions of MF decomposition into methanol and CO and methanol dehydration into DME.

Methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate: Synthesis and reactions with dimethyl malonate and methyl acetoacetate

Bromination–dehydrobromination of methyl (E)-3-(4-methylbenzenesulfonyl)prop-2-enoate gave methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate whose structure was determined by X-ray analysis. Methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate behaved as a synthetic equivalent of methyl 3-(4-methylbenzenesulfonyl)prop-2-ynoate in reactions with dimethyl malonate and methyl acetoacetate, which afforded the corresponding Michael adducts, trimethyl 3-(4-methylbenzenesulfonyl)prop-1-ene-1,1,2-tricarboxylate and dimethyl (Z)-2-acetyl-3-(4-methylbenzenesulfonyl)but-2-enedioate, respectively, via nucleophilic attack on the β-position with respect to the sulfonyl group.

Radical polymerization of acrylonitrile under the action of catalytic systems based on zero-valent copper

Specific features of the (co)polymerization of acrylonitrile in the presence of a catalytic system based on zero-valent copper and 2,2-bipyridyl in various solvents was studied. It is shown that these systems can be successfully used in the presence of halogen-containing initiators to obtain homo- and copolymers of acrylonitrile with dimethyl itaconate and methyl acrylate in the controlled mode. It was found that introduction of comonomers (methyl acrylate and dimethyl itaconate) in low concentrations has no effect on parameters of the acrylonitrile polymerization process, but strongly affects some properties and characteristics of samples being synthesized.

Experimental Study of the Effect of Post Processing Techniques on Mechanical Properties of Fused Deposition Modelled Parts

FDM (Fused Deposition Modelled) parts are chemically treated with two types of chemicals viz Dimethyl ketone (Acetone) and Methyl ethyl ketone to reduce the surface roughness. This chemical treatment method technique not only reduces surface roughness but also makes effect on strength of chemically treated parts of ABS (Acrylonitrile Butadiene Styrene) material. In this study Taguchi method of DOE (Design of Experiments) is conducted on test specimen of “tensile”, “bending” and “izod impact” components which are manufactured through Fused Deposition Modeling process using ABS-P400 material. DOE is conducted to optimize the effect of chemical treatment process parameters on strength of above specimen parts. The process parameters considered for the DOE are “different levels of concentration of chemical, temperature, time, layer thickness etc. ANOVA (Analysis of variance) is used to know the significance of contribution of each of these parameters. Results reveal that the prototypes when treated at optimum condition the tensile strength, flexural strength and izod impact strength improved significantly.

Assessment of cytotoxic and genotoxic potential of pyracarbolid by Allium test and micronucleus assay

The present study evaluates the cytotoxic and genotoxic potential of pyracarbolid using both micronuleus (MN) assay, in human lymphocytes, and Allium cepa assay, in the root meristem cells. In Allium test, EC50 value was determined in order to selecting the test concentrations for the assay and the root tips were treated with 25 ppm (EC50/2), 50 ppm (EC50) and 100 ppm (EC50 × 2) concentrations of pyracarbolid. One percent of dimethyl sulphoxide (DMSO) and methyl methane sulfonate (MMS) were used as negative and positive controls, respectively. In the micronucleus assay, the cultures were treated with four concentrations (250, 500, 750 and 1000 µg/ml) of pyracarbolid for 24 and 48 h, negative and positive controls were also used in the experiment parallely. The results showed that mitotic index (MI) significantly reduced with increasing the pyracarbolid concentration at each exposure time. It was also obtained that prophase and metaphase index decreased significantly in all concentration at each exposure time. Anaphase index decreased as well and results were found to be statistically significant, except 24 h. A significant increase was observed in MN frequency in all concentrations and both treatment periods when compared with the controls. Pyracarbolid also caused a significant reduction in the cytokinesis block proliferation index (CBPI) in all concentration and both exposure time.

Synthesis of 4-(2-(Piperazin-1-Yl)-7,8-Dihydro-5&lt;i&gt;H&lt;/i&gt;-Thiopyrano[4,3-&lt;i&gt;d&lt;/i&gt;]Pyrimidin-4-yl)Morpholine and 4-Morpholino-2-(Piperazin-1-Yl)- 7,8-Dihydro-5&lt;i&gt;H&lt;/i&gt;-Thiopyrano[4,3-&lt;i&gt;d&lt;/i&gt;]Pyrimidine 6,6-Dioxide

Two novel thiopyrano [4,3-d] pyrimidine derivatives 7 and 8 were synthesized from dimethyl 3,3'-thiodipropanoate through six steps including two times of cyclization, chlorination, oxidation, substitution with morpholine and piperazine and their structures were confirmed by1H NMR and MS spectrum. The total yield of the six steps was 18.6% (calculated from methyl dimethyl 3,3'-thiodipropanoate). The synthetic routes of them can be used to synthesize PI3K/mTOR inhibitors bearing a thiopyrano [4,3-d] pyrimidine nucleus.

Studies on volatile organic compounds of some truffles and false truffles

Results of solid phase micro-extraction coupled to gas chromatography and mass spectrometry analyses, accomplished on sporophores of 11 species of truffles and false truffles, are reported. Volatile organic compounds (VOCs) found in Gautieria morchelliformis were dimethyl sulphide, 1,3-octadiene, 3,7-dimethyl-1,6-octadien-3-ol, amorphadiene, isoledene and cis-muurola-3,5-diene. In Hymenogaster luteus var. luteus, presence of 1,3-octadiene, 1-octen-3-ol, 3-octanone, 3-octanol and 4-acetylanisole was revealed. Two VOCs, 4-acetylanisole and β-farnesene, constituted aroma of Hymenogaster olivaceus.Melanogaster broomeanus exhibited as components of its aroma 2-methyl-1,3-butadiene, 2-methylpropanal, 2-methylpropanol, isobutyl acetate, 3,7-dimethyl-1,6-octadien-3-ol, 3-octanone and β-curcumene. VOC profile of Octavianina asterosperma was characterised by the presence of dimethyl sulphide, ethyl 2-methylpropanoate, methyl 2-methylbutanoate and 3-octanone. Tuber rufum var. rufum and Pachyphloeus conglomeratus showed the presence of dimethyl sulphide only.

Preparation and Properties of Polysiloxane Modified Epoxy Encapsulating Material

In order to solve the poor toughness, fatigue durability and shock resistance defects of the cured epoxy resin, in this paper, the epoxy resin was modified via dichlorodiphenyl silane as a modifier. Then the electronic packaging materials were prepared using the modified EP as matrix, a nitrile rubber (CTBN) as a toughening agent, methyl nadic anhydride (MNA) as a curing agent, and 2, 4, 6 - tris (dimethyl amino methyl) phenol as a curing accelerator. The effects of raw materials ratio on the cured products’ properties was investigated. FT-IR, TG-DTG and DMA were used to test and characterize the product. And we determined the best raw materials ratio and reaction conditions. Finally epoxy encapsulating materials which have excellent mechanical properties, electrical properties were prepared.