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1、二、光化学反应基础二、光化学反应基础Thebasisofphotochemicalreaction1、光子、光子photon的能量的能量爱因斯坦爱因斯坦爱因斯坦爱因斯坦- -普朗克（普朗克（普朗克（普朗克（Einstein-PlanckEinstein-Planck）关系式：）关系式：）关系式：）关系式： = h = hc/ (J)(J)E= N0 h = N0 hc/ (KJ/mol)(KJ/mol)式中式中式中式中h hPlanckPlanck常数，常数，常数，常数，6.621034J.s6.621034J.s； 光子的频率，光子的频率，光子的频率，光子的频率，HzHz； c c光速，光速
2、，光速，光速，2.998102.998101010cm/scm/s； 光子的波长，光子的波长，光子的波长，光子的波长，cmcm；N N0 0阿佛加德罗常数，阿佛加德罗常数，阿佛加德罗常数，阿佛加德罗常数，6.02106.02102323/mol/mol。l l随着波长的增加，光子的能量减小。随着波长的增加，光子的能量减小。波长（波长（nm）能量（能量（kJ/mol）光的区域光的区域200300597.2398.4紫外光紫外光400700298.9170.8可见光可见光2000500059.723.9红外线红外线不同波长光的能量不同波长光的能量高能光，能引起光化高能光，能引起光化学反应（光离解）
3、学反应（光离解）低能光，不能引起低能光，不能引起光化学反应光化学反应l l例例1计算波长为计算波长为200nm紫外光的能量。紫外光的能量。一般化学鍵的键能大于一般化学鍵的键能大于一般化学鍵的键能大于一般化学鍵的键能大于167.44KJ/mol167.44KJ/mol2、光化学、光化学photochemistry反应原理反应原理光化学反应光化学反应：由一个原子、分子、自由基或离：由一个原子、分子、自由基或离：由一个原子、分子、自由基或离：由一个原子、分子、自由基或离子吸收一个光子后所引发的反应。子吸收一个光子后所引发的反应。子吸收一个光子后所引发的反应。子吸收一个光子后所引发的反应。初级过程：初
4、级过程： 引发：引发：引发：引发：A(A(分子分子分子分子) )hhA A*(*(激发态分子激发态分子激发态分子激发态分子) )次级过程：次级过程： 离解：离解：离解：离解：A*A*C+C+ 与其他分子反应生成新的物种：与其他分子反应生成新的物种：与其他分子反应生成新的物种：与其他分子反应生成新的物种：A*+BA*+BD+D+ 与惰性与惰性与惰性与惰性inertia分子碰撞失活分子碰撞失活分子碰撞失活分子碰撞失活( (返回基态返回基态返回基态返回基态) )：A*+MA*+MA+MA+M 发光而失活发光而失活发光而失活发光而失活( (返回基态返回基态返回基态返回基态) )：A*A*A Ahh3、
5、 大大 气气 中中 重重 要要 吸吸 光光 物物 质质 的的 光光 离离 解解Photodissociationl l吸光物质吸光物质Absorbingmaterials高层大气：高层大气：高层大气：高层大气：N N2 2、OO2 2、OO33（290nm290nm）低层大气：低层大气：低层大气：低层大气：NONO2 2、SOSO2 2等等等等l l氧和氮的光离解氧和氮的光离解氧氧分分子子键键能能：493.8kJ/mol（240nm以以下下紫外光可引发）：紫外光可引发）：O2hO+O氮氮分分子子键键能能：939.4kJ/mol（127nm，仅仅限于臭氧层以上）：限于臭氧层以上）：N2hN+N当
6、当当当入入入入射射射射波波波波长长长长低低低低于于于于79.6nm79.6nm(1391kJ/mol)(1391kJ/mol)时时时时，N N2 2将电离成将电离成将电离成将电离成N N2 2。l l臭氧臭氧ozone和过氧化物和过氧化物Peroxide的光离解的光离解l l臭氧臭氧臭氧臭氧分子键能：分子键能：分子键能：分子键能：101.2kJ/mol101.2kJ/mol220220290nm290nm强吸收（强吸收（强吸收（强吸收（254nm254nm最强吸收）最强吸收）最强吸收）最强吸收）290290320nm320nm少量吸收少量吸收少量吸收少量吸收450450700nm700nm微弱
7、吸收微弱吸收微弱吸收微弱吸收离解反应：离解反应：离解反应：离解反应：OO3 3hhOO2 2+O+O烷基过氧化物烷基过氧化物烷基过氧化物烷基过氧化物在在在在300300700nm700nm范围有微弱吸收，范围有微弱吸收，范围有微弱吸收，范围有微弱吸收，光离解反应：光离解反应：光离解反应：光离解反应： ROORROORh h RO+RORO+ROl lNO2的光离解的光离解键键键键能能能能：300.5300.5kJ/molkJ/mol（300300400nm400nm吸吸吸吸光光光光），光光光光离离离离解反应：解反应：解反应：解反应：NONO2 2hhNO+ONO+OOO2 2+O+OMMOO3
8、 3MMNONO2 2是是是是污污污污染染染染大大大大气气气气中中中中最最最最重重重重要要要要的的的的吸吸吸吸光光光光物物物物质质质质, ,在在在在低低低低层层层层大大大大气气气气中中中中可可可可以以以以吸吸吸吸收收收收全全全全部部部部来来来来自自自自太阳的紫外光和部分可见光。太阳的紫外光和部分可见光。太阳的紫外光和部分可见光。太阳的紫外光和部分可见光。OO3 3的唯一人为来源的唯一人为来源的唯一人为来源的唯一人为来源OXIDIZING NATURE OF THE ATMOSPHERE Earths atmosphere is oxidizing due to presence of O2SO
9、2 - SO42-; CH4 - CO; CO - CO2; NO2 - HNO3 Radicals are oxidizing agents in the atmosphere OH is the cleansing agent of the atmosphere Key to understanding atmospheric oxidant chemistry Understand radical cycling but radical cycle is intimately connected to oxidant chemistry of other trace compounds
10、including O3 Start with O3O3 is important from chemical, climate, and health perspectivesATMOSPHERIC O3 A BRIEF HISTORY 1840: Ozone discovered in 1840 by C. F. Schnbein thought it was made up of oxygen and hydrogen 1848: Systematic measurement attempts curiousity, growing interest in env., health ef
11、fects, economy of nature 1861: Odling suggested that ozone was O3 1930: Chemical mechanism for O3 layer postulated 1952: O3 identified as component of chemical smogChristian Frederich SchnbeinOZONE AND HEALTH 90% of O3 is in the stratosphere; O3 layer with max 9 ppm Absorption of = 200-320 nm (UV-B
12、and UV-C) by strat. O3Source: Stratospheric Ozone, NASA/GSFCOZONEANDSTRATOSPHERICTEMPERATUREOZONEANDSTRATOSPHERICTEMPERATURE Local heating of the stratosphere due to UV absorption by O3 Tropospheric O3 is also an important greenhouse gasSource: Stratospheric Ozone, NASA/GSFCSource: Environmental Sci
13、ence, Cunningham, P. W. and B. W. Saigo, 2001O3O(1D)O(3P)2OHSolar radiation, wavelength 290-320 nmH2OO2, N2O2OZONEANDATMOSPHERICCHEMISTRYOZONEANDATMOSPHERICCHEMISTRY O3 is the primary source of tropospheric OH OH is atmospheric detergent LATITUDINAL & TEMPORAL VARIATION OF TOTAL O3 Total O3 in range
14、 of 300-400 DU Patterns due to stratospheric circulation Low total O3 at high southern lat in southern spring due to ozone holeDobson units 1 DU = 2.69 x 1016 molecules O3 cm-2Source: Stratospheric Ozone, NASA/GSFCSTRATOSPHERIC O3 CHEMISTRYTHE CHAPMAN MECHANISM FOR STRATOSPHERIC O3 Cycling between O
15、, O2, and O3 Source: Stratospheric Ozone, NASA/GSFCMISSING CHEMISTRY IN CHAPMAN MECHANISM Global O3 production rate = 5 times destruction rate Imbalance suggests overest. of prodn. or underest. of loss O3 production well constrained by good spectroscopic data Implies missing chemical sinks for Ox Re
16、actions of radicals with O and/or O3 But radicals will also be consumed by reaction measuredcalculatedSource: Stratospheric Ozone, NASA/GSFCCATALYTIC OX DESTRUCTION IN THE STRATOSPHERE Radical chain reactions X + O3 XO + O2 XO + O X + O2 Net: O + O3 2O2 X in the stratosphere H, OH, NO, Cl HOx, NOx,
17、and Clx HOx = H + OH + HO2 NOx = NO + NO2 Clx = Cl + ClO Reservoirs tie up active radicals e.g. ClO + NO2 ClONO2 Stratospheric Clx precursorsSource: Stratospheric Ozone, NASA/GSFCColumn O3 (DU) ANTARCTIC TOTAL OZONE DECREASE Depletion of total column O3 starting in mid- to late-70s during SH spring
18、Gas-phase chemistry predicted smaller decreases & not over AntarcticaO3Source: Stratospheric Ozone, NASA/GSFCSource: Farmann et al., Nature, v. 315, May 1985 ALTITUDE DEPENDENCE OF ANTARCTIC O3 DECREASE Strong depletion between 12 and 20 km Gas phase chemistry predicted decrease near 40 kmSource: St
19、ratospheric Ozone, NASA/GSFC TEMPORAL DEPENDENCE OF ANTARCTIC O3 DECREASE Depletion begins around Sep 1. & minimum is reached around Oct 1Source: NOAA/CMDL REACTIONS ON POLAR STRATOSPHERIC CLOUDS Conversion of inactive Cl to active Cl and removal of NOxSource: Stratospheric Ozone, NASA/GSFCROLE OF M
20、ETEOROLOGY Low temps.PSC formation release of active Cl and removal of NOxStrong vortexIsolates air from mid-lats. prevents high O3 air influxFigure shows strong polar vortex旋涡(as shown by size of wind vectors) & low polar temps. (as shown by colors) at various altitudes in the southern hemisphere s
21、tratosphereSource: Stratospheric Ozone, NASA/GSFCNORTHERN vs SOUTHERN HEMISPHERE O3 TRENDS Vortex not as strong and temps. not as low in NHSource: Stratospheric Ozone, NASA/GSFCPROJECTED CHANGES IN STRATOSPHERIC Clx Montreal Protocol and subsequent amendments will have signifcant impacts on projecte
22、d Clx loading of stratosphere(ppb)Source: Stratospheric Ozone, NASA/GSFC WMO 1998 Scientific Assessment of Ozone Depletion Ozone depletion in 2050 would be at least 50% at midlatitudes in the Northern Hemisphere and 70% at midlatitudes in the Southern Hemisphere, about 10 times larger than today Sur
23、face UV-B radiation in 2050 would at least double at midlatitudes in the Northern Hemisphere and quadruple at midlatitudes in the Southern Hemisphere compared with an unperturbed atmosphere. This compares to the current increases of 5% and 8% in the Northern and Southern Hemispheres, respectively, s
24、ince 1980 ESTIMATED IMPACTS OF Clx CONTROLSTROPOSPHERIC O3 CHEMISTRYSource: EPA Tropospheric O3 generally less than 100 ppb away from urban areasTROPOSPHERIC O3Source: Wang et al., 1998l lOO3 3 chemical production in stratosphere followed chemical production in stratosphere followed by downward tran
25、sport to the troposphere by downward transport to the troposphereO2O(3P)Solar radiation, ( 240 nm)O3O2Solar radiation ( CO2 + O3 Catalytic role of NOx (NO + NO2) in recycling HO2 to OH Coupling between OH and HO2 (HOx) via NOCO OXIDATION CYCLE O3 PRODUCTIONCO2O3NO or O3 OHHO2COO2Net: CO + O3 - CO2 +
26、 O2 Chemical O3 destruction Coupling between OH and HO2 (HOx) via O3CO OXIDATION CYCLE O3 DESTRUCTIONCO2O32O21.O3 + hv O2 + O(1D)2. O(1D) + M O + M3. H2O + O(1D) 2OH4. RH + OH RO2 + H2O5. RO2 + NO RO + NO26. RO + O2 RCHO + HO27. HO2 + NO OH + NO28. HO2 + HO2 H2O2 + O29. OH + NO2 + M HNO3 + MSCHEMATI
27、C OF HYDROCARBON CHEMISRYO2Net rxns 1-7:RH + 4O2 RCHO + 2O3 + H2OSource: Introduction to Atmospheric Chemistry, Jacob, D. J., 1999can produce more O3ROLEOFNOROLEOFNOX XINOINO3 3CHEMICALPRODUCTIONCHEMICALPRODUCTIONl lCycling of Cycling of HOHOx x (OH + HO (OH + HO2 2) by ) by NONOx x vs. radical vs.
28、radical termination reactionstermination reactionsl lToo little Too little NONOx x: Radical termination (e.g. HO: Radical termination (e.g. HO2 2 + HO + HO2 2) ) rather than radical cycling (e.g. HOrather than radical cycling (e.g. HO2 2 + NO) leading to + NO) leading to OO3 3 chemical destruction c
29、hemical destructionl lToo much Too much NONOx x: Radical termination by alternate route : Radical termination by alternate route (e.g. OH + NO(e.g. OH + NO2 2) as well as short-term O) as well as short-term O3 3 destruction destruction by NO + Oby NO + O3 3 - NO - NO2 2 = implications for O = implic
30、ations for O3 3 peak peak downwind of strong NOdownwind of strong NOX X sources sourcesNOx- AND HYDROCARBON-LIMITED REGIMESNOx limitedHydrocarbon limitedComplications:Natural emissions of hydrocarbons are importantTransport of pollutants into and out of regionSource: Introduction to Atmospheric Chem
31、istry, Jacob, D. J., 1999l lQuestions:Questions:l lNONOx x or HC emission controls or combination or HC emission controls or combinationl lDegree of emission controlsDegree of emission controlsl lUncertaintiesUncertaintiesl lReliability of emission inventoriesReliability of emission inventories清单清单(
32、e.g. natural (e.g. natural hydrocarbon inventories)hydrocarbon inventories)l lReliability of air quality models (e.g. local Reliability of air quality models (e.g. local vsvs transported NOtransported NOx x/HC/O/HC/O3 3) ) ISSUES IN O3 POLLUTION CONTROL1998 MEASURED SURFACE OZONE CONCENTRATIONS2nd h
33、ighest daily max 1-hr (ppb)65 65-124125-16465-84205-404Source: 1998 EPA National Trends Report11815316936141155167165-2044th highest daily max 8-hr (ppb) 50 ppbv and 10-20% of crops in areas with growing-season mean O3 50 ppbv Potentially large impact in future years:Year 2100 IPCC scenario from HAR
34、VARD model gives 50% of population in areas with max. monthly-mean O3 85 ppbv, and 50% of crops in areas with growing season mean O3 70 ppbvATMOSPHERICAEROSOLSANDACIDRAINATMOSPHERICAEROSOLSANDACIDRAINCombustion generated Aerosols and acid rain can effect natural & managed ecosystemsRO-NORO-NO2 2键能：键
35、能：键能：键能：199.4kJ/mol199.4kJ/mol（吸收（吸收（吸收（吸收120120335nm335nm）：）：）：）：硝酸：硝酸：硝酸：硝酸：HNOHNO3 3（HONOHONO2 2）hhHOHO+NO+NO2 2烷基硝酸酯：烷基硝酸酯：烷基硝酸酯：烷基硝酸酯：RONORONO2 2hh RO+NORO+NO2 2对对对对于于于于300nm300nm以以以以上上上上的的的的光光光光的的的的吸吸吸吸收收收收速速速速度很小度很小度很小度很小 l硝酸硝酸硝酸硝酸nitricacidnitricacid和烷基硝酸酯和烷基硝酸酯和烷基硝酸酯和烷基硝酸酯AlkylnitratesAlkyl
36、nitrates的光离解的光离解的光离解的光离解l l亚硝酸亚硝酸nitrite和烷基亚硝酸酯和烷基亚硝酸酯alkylnitrite的的光离解光离解HO-NOHO-NO键能：键能：键能：键能：201.1kJ/mol201.1kJ/molH-ONOH-ONO键能：键能：键能：键能：324.0kJ/mol324.0kJ/molHNOHNO2 2对对对对200200400nm400nm的光有吸收，发生光离解：的光有吸收，发生光离解：的光有吸收，发生光离解：的光有吸收，发生光离解：HONOhHO+NOHNO2hH+NO2RONOhNO+RO仅仅仅仅次次次次于于于于NONO2 2光光光光离离离离解解解解
37、的的的的最最最最重重重重要要要要的的的的光光光光离解初级反应。离解初级反应。离解初级反应。离解初级反应。l l醛的光离解醛的光离解（CH2O和和CH3CHO）H-CHO键键 能能 ： 365.5kJ/mol（ 吸吸 收收 240360nm），光离解反应：），光离解反应： 甲醛甲醛H2COhH+HCOH2COhH2+CO 乙醛乙醛CH3CHOhH+CH3COCH3CHOhCH3+HCOCH3CHOhCH4+COl l卤代烃卤代烃halocarbon的光离解的光离解卤代甲烷的光解：卤代甲烷的光解：CH3XhCH3+X式中式中X代表代表Cl, Br, I, F。键键键键 强强强强 顺顺顺顺 序序序序
38、 ： CHCH3 3 F F CHCH3 3 HHCHCH3 3ClClCHCH3 3BrBrCHCH3 3I Il lSO2的光吸收的光吸收SO2键键能能：545.1kJ/mol（200nm），吸吸收收三个波段：三个波段：340340400nm400nm（极弱）（极弱）（极弱）（极弱）240240330nm330nm（较强）（较强）（较强）（较强）280280240nm240nm（很强）（很强）（很强）（很强）SO2不能光离解，只能形成激发态分子：不能光离解，只能形成激发态分子：SO2hSO2活活活活性性性性粒粒粒粒子子子子：HOHO、RORO、RORO2 2、H H、HCOHCO、CHCH
39、3 3、CHCH3 3COCO等等等等自自自自由由由由基基基基被被被被称称称称为为为为大大大大气气气气中中中中的的的的“ “活活活活性性性性粒粒粒粒子子子子” ”，它它它它们们们们性性性性质质质质特特特特别别别别活活活活泼泼泼泼，能能能能够够够够引引引引发发发发一一一一系系系系列列列列反反反反应应应应，参参参参与与与与很很很很多多多多的的的的污污污污染染染染物物物物的的的的化化化化学学学学转转转转化化化化过过过过程程程程，导导导导致致致致生生生生成成成成各种各样的二次污染物。各种各样的二次污染物。各种各样的二次污染物。各种各样的二次污染物。三、大气中重要自由基的来源三、大气中重要自由基的来源s
40、ourceoffreeradicalsintheatmospherel l键的断裂与自由基（键的断裂与自由基（freeradical）的形成：）的形成：l l不对称裂解形成正、负离子；不对称裂解形成正、负离子；不对称裂解形成正、负离子；不对称裂解形成正、负离子；l l对称裂解形成自由基。对称裂解形成自由基。对称裂解形成自由基。对称裂解形成自由基。l l自由基自由基具有强烈的夺取电子倾向和结合力。具有强烈的夺取电子倾向和结合力。l l自由基自由基具有很强的氧化能力和化学活性。具有很强的氧化能力和化学活性。l l1、HO的来源的来源HOH2OO+ O2O3315nmHNO2400nmH2O2370
41、nmNOHO2O2H+HCOHCHO313nmHOHO基的形成途径基的形成途径基的形成途径基的形成途径（1 1）HONOHONOHOHONONO（ 400nm400nm）（2 2）H H2 2OO2 22HO2HO（ 300nm300nm）（3 3）OOH H2 2OO2HO2HO（OO来自来自来自来自OO3 3的光离解）的光离解）的光离解）的光离解）（4 4）HOHO2 2NONOHOHONONO2 2（HOHO2 2来自来自来自来自HCHOHCHO光离解，光离解，光离解，光离解，产生的产生的产生的产生的H H与与与与OO2 2作用）作用）作用）作用）HO基的基的形成途径形成途径l l大气中
42、大气中HO的浓度的浓度concentration测算测算：用用用用数数数数学学学学模模模模拟拟拟拟算算算算出出出出大大大大气气气气中中中中HOHO基基基基的的的的全全全全球球球球平平平平均均均均浓浓浓浓度度度度约约约约为为为为7107105 5个分子个分子个分子个分子/cm/cm3 3；用用用用激激激激光光光光共共共共振振振振荧荧荧荧光光光光光光光光谱谱谱谱法法法法测测测测定定定定HOHO基基基基的的的的浓浓浓浓度度度度范范范范围围围围为为为为3 35105104 4个分子个分子个分子个分子/cm/cm3 3，浓浓浓浓度度度度数数数数值值值值随随随随纬纬纬纬度度度度、高高高高度度度度及及及及地
43、地地地区区区区的的的的不不不不同同同同而而而而变变变变化化化化，与季节有关。与季节有关。与季节有关。与季节有关。HOHO在对流层中随高度和纬度的分布在对流层中随高度和纬度的分布在对流层中随高度和纬度的分布在对流层中随高度和纬度的分布HOHO最最最最高高高高浓浓浓浓度度度度出出出出现现现现在在在在热热热热带带带带（温温温温度度度度高高高高，太太太太阳阳阳阳辐辐辐辐射射射射强强强强）；在在在在两两两两半半半半球球球球间分布不对称。间分布不对称。间分布不对称。间分布不对称。HOHO和和和和HOHO2 2自由基的日变化曲线自由基的日变化曲线自由基的日变化曲线自由基的日变化曲线光光光光化化化化学学学学生
44、生生生成成成成产产产产率率率率白白白白天天天天高高高高于于于于夜夜夜夜间间间间，峰值出现在阳光最强的时间。峰值出现在阳光最强的时间。峰值出现在阳光最强的时间。峰值出现在阳光最强的时间。夏季高于冬季。夏季高于冬季。夏季高于冬季。夏季高于冬季。2、HO2的来源的来源l l由由CH2O、CH3ONO以及以及H2O2形成：形成： （1 1）HCHOHCHOHH HCOHCO （ 313nm313nm） HH OO2 2HOHO2 2 HCOHCO OO2 2HOHO2 2 COCO （2 2）CHCH3 3ONOONONONO CHCH3 3OO （ 300300400nm400nm）CHCH3 3O
45、O OO2 2HOHO2 2 CHCH2 2OO （3 3）H H2 2OO2 22 2HOHO （ 370nm370nm） 2 2HOHO 2H2H2 2OO2 22 2HOHO2 2 2H2H2 2OO 2 2HOHO 2CO2CO2CO2CO2 22 2H H 2 2H H OO2 22 2HOHO2 2 3、CH3、CH3O、RO2的来源的来源l lCH3：CH3CHOhCH3+HCOCH3COCH3hCH3+CH3COl lCH3O：CH3ONOhCH3O+NOl lCH3O2和和RO2：CH3+O2CH3O2RO2RO2四、氮氧化物的转化四、氮氧化物的转化Transformatio
46、nl l1、NOx的光化学反应的光化学反应PhotochemicalreactionPhotochemicalreactionNO(nitricoxide)NO(nitricoxide)、NONO22(nitrogendioxide)(nitrogendioxide)与与与与OO33(ozone)(ozone)之间存在着的化学循环之间存在着的化学循环之间存在着的化学循环之间存在着的化学循环chemicalcyclingchemicalcycling是是是是大气光化学过程的基础。大气光化学过程的基础。大气光化学过程的基础。大气光化学过程的基础。当阳光照射到含有当阳光照射到含有当阳光照射到含有当阳
47、光照射到含有NONO和和和和NONO2 2的空气时，反应：的空气时，反应：的空气时，反应：的空气时，反应：NONO2 2hhNO+ONO+OOO2 2+O+OMMOO3 3MMOO3 3NONONONO2 2+O+O2 22、NOx的气相转化的气相转化l lN2O光解光解photolysis：N2OhN2+O清除清除elimination：N2OON2+O2N2OONO+NO2、NOx的气相转化的气相转化gasphasetransformationl lNONONO OO3 3 NONO2 2+O+O2 2HO+NOHO+NOHONOHONORO+NORO+NORONORONORORO2 2+
48、NO+NORO+NORO+NO2 2HOHO2 2+NO+NOHO+NOHO+NO2 2RCOORCOO2 2+NO+NORO+CO+NORO+CO+NO2 2l lNO2HO+NOHO+NO2 2 HNOHNO3 3OO3 3+NO+NO2 2 NONO3 3+O+O2 2NONO3 3可以和可以和可以和可以和NONO反应或光解作用再生成反应或光解作用再生成反应或光解作用再生成反应或光解作用再生成NONO2 2，或者，或者，或者，或者再与再与再与再与NONO2 2进一步反应生成进一步反应生成进一步反应生成进一步反应生成N N2 2OO5 5。N N2 2OO5 5与与与与H H2 2OO作用
49、形成作用形成作用形成作用形成HNOHNO3 3。 PAN（过过氧氧乙乙酰酰基基硝硝酸酸酯酯 peroxyacetylnitrate）CHCH3 3CO+OCO+O2 2 CHCH3 3COOCOO2 2CHCH3 3COOCOO2 2NONO2 2CHCH3 3COOCOO2 2NONO2 2 PANPAN具具具具 有有有有 热热热热 不不不不 稳稳稳稳 定定定定 性性性性 ， 遇遇遇遇 热热热热 会会会会 分分分分 解解解解 回回回回 到到到到CHCH3 3COOCOO2 2和和和和NONO2 2。3、NOx的液相转化的液相转化liquidPhasetransformationNOx可溶于大
50、气的水中，构成一个液相平衡可溶于大气的水中，构成一个液相平衡体系。体系。l lNOxNOx的液相平衡的液相平衡的液相平衡的液相平衡NO(gNO(g) )NO(aqNO(aq) )aquaticNONO2 2(g)(g)NONO2 2(aq)(aq)2NO2NO2 2(aq)(aq)N N2 2OO4 4NO(aqNO(aq)+NO)+NO2 2(aq)(aq)NN2 2OO8 8(aq)(aq)对于对于对于对于NO-NONO-NO2 2体系，存在液相平衡：体系，存在液相平衡：体系，存在液相平衡：体系，存在液相平衡：2NO2NO2 2(g)+H(g)+H2 2OO2H2H+ +NO+NO2 2- -+NO+NO3 3- -NO(gNO(g)+NO)+NO2 2(g)+H(g)+H2 2OO2H2H+ +2NO+2NO2 2- -l lNH3和和HNO3的液相平衡的液相平衡aquaticbalanceNHNH3 3(g)+H(g)+H2 2OONHNH3 3 HH2 2OONHNH3 3 HH2 2OONHNH4 4+ +OH+OH- -HNOHNO3 3(g)+H(g)+H2 2OOHNOHNO3 3 HH2 2OOHNOHNO3 3 HH2 2OOHH+ +NO+NO3 3- -
