学科分类
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21 个结果
  • 简介:Reviewsonthecunentstudiesontheseatoairfluxofdimethylsulfide(DMS)havebeenmadeathomeandabroad,pointingoutthatthefluxofDMSisinfluencedbymanyfactors.Thereisgreatdifferencebetweentheresultscomingfiomdifferentmodels.Besides,thispaperfocusesontheoxidationmechanismsofDMSbyOHandNO3radicalsafteritenterstheatmosphere,theoxidationproducts'contributiontoacidrainandfogandtherelationshipsamongtheDMS,CCNandclimatesystem.

  • 标签: DIMETHYL sulfide sea-air flux marine atmosphere
  • 简介:Thethreeprojects——“Synthesisofdimethylcarbonatethroughureaalcoholysis”,“CleanprocessandcatalystforMDIproduction”and“Synthesisofdiphenylcarbonatethroughtrans-esterification”——jointlyperformedbyChengduOrganicChemicalCo.,Ltd.,PetroChinaUrumqiBranchCompanyandPetroChinaJilinBranchCompanyhavemetthetargetsspecifiedinthecontractandpassedtheexperts'acceptancecheckorganizedbyPetroChina.Thesethreeprojectsrepresentacleanproductionprocessthatappliesureaordimethylcarbonateinlieuofphosgeneasthefeedstocktomakedimethylcarbonate,

  • 标签: 二甲基碳酸盐 成都化学有限公司 中国石化公司 清洁生产 生产技术
  • 简介:AnefficientprocessfortheconversionofdimethyloxalateintoethyleneglycolwithhighselectivityandhighyieldoverCu2Owasinvestigated.InsituformedCuasatruecatalyticallyactivespeciesshowedagoodcatalyticperformanceforDMOconversiontoproduceEGin95%yield.

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  • 简介:过量音量(VE),超声的速度(u),isentropic压缩的可能性(K)和粘性()为有在303.15点的1,2-dichlorobenzene,1,3-dichlorobenzene,1,2,4-trichlorobenzene,o-chlorotoluene,m-chlorotoluene,p-chlorotoluene,o硝基甲苯和m硝基甲苯的dimethylformamide(DMF)的二进制混合物,K被学习。过量卷数据展览在为有1,2-dichlorobenzenes和1,3-dichlorobenzenes和性质的dimethylformamide的混合物的符号的倒置在为有1,2,4-trichlorobenzene,o硝基甲苯和m硝基甲苯的dimethylformamide的混合物的全部作文范围上是完全积极的。在另一方面,数量为有chlorotoluenes的dimethylformamide的混合物是否定的。Isentropic压缩的可能性(K)从精确健全速度和密度数据为一样的系统被计算了。进一步,从理想的行为的isentropic压缩的可能性(K)的偏差也是计算的。K值在在所有二进制混合物的全部音量部分范围上是否定的。试验性的健全速度数据以免费长度理论(FLT)和碰撞因素理论(CFT)被分析。粘性数据根据相应州的途径被分析。测量数据根据在不同分子之间的分子间的相互作用被讨论。

  • 标签: 二元液体混合物 二甲基甲酰胺 过剩容积 超声性质 输运性质 分子间相互作用
  • 简介:OrderedmesoporouscopperincorporatedAl2O3(Cu/Al2O3)withhighCudispersionwerepreparedbyafacilesolutioncombustionsynthesismethodusingaluminumnitrateandcoppernitrateasoxidantsandureaasfuel.Itisafacileandgreenroutetosynthesizecatalystsfordimethyletherdirectlyfromsyngas.Cu/Al2O3catalystswerecharacterizedbyXRD,N2adsorption–desorption,SEM-EDS,andH2-TPR.Theresultsindicatethatthecatalystsobtainanorderedmesoporousstructureandcopperishomogenouslydispersed.ThemesoporousCu/Al2O3catalystswereutilizedasbifunctionalcatalystsinsyngastodimethyletherreaction(STD).ThecoppercontentaffectsthecatalyticperformanceinSTDreaction.TheCOconversionandDMEselectivityofCu/Al2O3with15%coppermolarratioachieve52.9%and66.1%,respectively.Moreover,themesoporousCu/Al2O3catalystsshowexcellentstabilityinSTDreaction.

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  • 简介:Micro-mesoporouscompositemolecularsievesH-ZSM-5/MCM-41werepreparedbythehydrothermaltechniquewithalkali-treatedH-ZSM-5zeoliteasthesourceandcharacterizedbyscanningelectronmicroscopy,transmissionelectronmicroscopy,energydispersivespectroscopy,X-raydiffraction,N2adsorption-desorptionmeasurementandNH3temperature-programmeddesorption.ThecatalyticperformancesforthemethanoldehydrationtodimethyletheroverH-ZSM-5/MCM-41wereevaluated.Amongthesecatalysts,H-ZSM-5/MCM-41preparedwithNaOHdosage(nNa/nSi)varyingfrom0.4to0.47presentedexcellentcatalyticactivitywithmorethan80%methanolconversionand100%dimethyletherselectivityinawidetemperaturerangeof170—300℃,andH-ZSM-5/MCM-41preparedwithnNa/nSi=0.47showedconstantmethanolconversionofabout88.7%,100%dimethyletherselectivityandexcellentlifetimeat220℃.Theexcellentcatalyticperformanceswereduetothehighlyactiveanduniformacidicsitesandthehierarchicalporosityinthemicro-mesoporouscompositemolecularsieves.ThecatalyticmechanismofH-ZSM-5/MCM-41forthemethanoldehydrationtodimethyletherprocesswasalsodiscussed.

  • 标签: HIERARCHICAL POROSITY H-ZSM-5 composite molecular SIEVE
  • 简介:Anewformulawaspresentedforlocatingdoublebondpositionindodecenols,tetrade-cenols,hexadecenolsandtheiracetates,basedonmassspectraldataofdimethyldisulfidederivatives.Inthisprocedure,molecularionandbasepeakionwereutilizedascharacteristicparameterstoidentifythepositionalisomers.Themethodwastestedwithmassspectraof25dimethyldisulfldederivativesofmono-unsaturatedacetatesandalcohols,andtheoriginaldouble-bondpositionineachisomerwaslocatedunambiguously.

  • 标签: MASS spectrometry double bond positional ISOMER
  • 简介:HighlyactiveandselectiveCu/SiO2catalystsforhydrogenationofdimethyloxalate(DMO)toethyleneglycol(EG)weresuccessfullypreparedbymeansofaconvenientone-potsyntheticmethodwithtetraethoxysilane(TEOS)asthesourceofsilica.XRD,H2-TPR,SEM,TEM,XRFandN2physisorptionmeasurementswereperformedtocharacterizethetextureandstructureofCu/SiO2catalystswithdifferentcopperloadings.TheactivecomponentswerehighlydispersedonSiO2supports.Furthermore,thecoexistenceofCu0andCu+contributedalottotheexcellentperformanceofCu-TEOScatalysts.TheDMOconversionreached100%andtheEGselectivityreached95%at498Kand2MPawithahighliquidhourlyspacevelocityoverthe27-Cu-TEOScatalystwithanactualcopperloadingof19.0%(massfraction).

  • 标签: CU/SIO2催化剂 草酸二甲酯 TEOS 乙二醇 催化性能 加氢
  • 简介:Variousenolsof2-acylmethyl-4,4-dimethyl-2-oxazolineswerepreparedinmoderateyieldsviaultrasonicallycatalyzedreactionsof2,4,4-trimethyl-2-oxazolinewitharenecarboxylicestersinthepresenceofUDP-t-BuCl-i-Pr2NHsystem.

  • 标签: Ultrasonically dispersed POTASSIUM 2 4 4-trimethyloxazoline
  • 简介:TherearesomeIndicationsthttherpesaimplexvirus(HSV)maybemutagenic.SpecificchromosomalchangeshavealsobeendemonstratedInculturedcellsinfectedwithHSV.TofurtherInvestigatethemutagenicactivityofHSVtype2(HSV-2)weusedmouseskinasamodelsystemforcardnogenetls.Inoculationofthebackskinof4-week-oldSencarmkewithlivevirustwiceperweekforoneweekorwithInactivatedvirustwiceperweekfortwoweekswasusedtoInitiatethemouseakin.AfterInitiationwithHSV-2,12-O-tetradecanoylphorbol-13-acetale(TPA)wasappliedtwiceweeklyfor50weeksasapromoter.Duringaperiodof52weeks,noskincarcinomawasfoundIntheexperimentalgroups,whereas55%ofcontrolmicetreatedwith9,10-dlmethy1-1,2-benzanthracene(DMBA)andthenwithTPA-developedskincarcinoma.TheresultsdemonstratethatHSV-2couldnotsubstituteforDMBAinthisanimalmodeloftwo-stageskincarcinogenesis.

  • 标签: DMBA weekly CARCINOGENESIS twice HERPES Initiation
  • 简介:Thetitlecompounds5a-5cwerepreparedviathereactionofmethyl2-perfluoroal-kynoates(4)withmethyl5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate(3),whichwasobtainedfromthereactionofmethylpropynate(2)withacetylmethylenetriphenylphosphorane(1)at-5-0℃.IntramoleculareliminationofPh3POtookplacewhencompound5washeatedinaqueousmethanolat115-120℃insealedtube,yieldingdimethyl2-trifluoromethyl-4-methylisophthalate(6a)from5aandmethyl5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate(6b)from5b,respectively.Thestructuresofcompounds5,6aand6bwereconfirmedbyIR,MS,1HNMR,19FNMRand13CNMRspectroscopyandelementalanalyses.Rectionmechanismsfortheformationofcompounds5,6aand6bwereproposed.

  • 标签: Phosphorane polysubstituted ARENE INTRAMOLECULAR CYCLIZATION
  • 简介:热行为,机制和在一个规划温度的模式的标题混合物的发热的第一阶段的分解反应的运动参数借助于DSC,TG-DTG和红外被调查了。反应机制被建议。在微分形式,明显的激活精力(Ea)和这反应的pre指数的因素(A)的实验运动模型功能是(1-)?1.119,211.3kj/mol和1020.2s?1分别地。混合物的热爆炸的批评温度是202.2爠慥瑣潩?㈠低??湡敧漠??????????????鈿酌顛鱎?????疞????陴?陴?T

  • 标签: DECOMPOSITION GLYCOLURIL KINETICS mechanism
  • 简介:Anovelflower-likehydratedmagnesiumcarbonatehydroxide,Mg_5(CO_3)_4(OH)_2·4H_2O,withmicro-structurecomposedofindividualthinnano-sheetswassynthesizedusingafacilesolutionroutewithouttheuseoftemplateororganicsurfactant.Reactiontimehasanimportanteffectonthefinalmorphologyoftheproduct.Themicro-structureandmorphologyofMg_5(CO_3)_4(OH)_2·4H_2OwerecharacterizedbymeansofX-raydiffractometry(XRD),field-emissionscanningelectronmicroscopy(FE-SEM).Brunauer-Emmett-Teller(BET)surfaceareasofthesampleswerealsomeasured.Theprobableformationmechanismofflower-likemicro-structurewasdiscussed.ItwasfoundthatMg_5(CO_3)_4(OH)_2·4H_2Owithflower-likemicro-structurewasanovelandefficientcatalystforthesynthesisofdiphenylcarbonate(DPC)bytransesterificationofdimethylcarbonate(DMC)withphenol.

  • 标签: 碳酸镁氢氧化 合成 微观结构 催化活性 酯交换反应