影響汽油氧化安定性的(de)因素

汽(qi)油(you)(you)在常(chang)溫和(he)液相(xiang)時(shi)抵抗大氣(或(huo)氧氣)的作(zuo)用而(er)保持其性(xing)能不(bu)發生變化的能力，叫氧化安定(ding)性(xing)。汽(qi)油(you)(you)在貯存(cun)和(he)使用過程(cheng)中(zhong)(zhong)，常(chang)常(chang)發現(xian)汽(qi)油(you)(you)顏色(se)變深，產生沉淀(dian)(dian)物，含鉛汽(qi)油(you)(you)還會(hui)出現(xian)灰白色(se)沉淀(dian)(dian)。這(zhe)都是因為汽(qi)油(you)(you)中(zhong)(zhong)某些成分被空氣中(zhong)(zhong)氧氣氧化的結果。

影響其汽(qi)油(you)安(an)定(ding)(ding)性(xing)的根本的原因在(zai)(zai)于(yu)汽(qi)油(you)的化學組成部(bu)分(fen)。組成汽(qi)油(you)的各(ge)種烴(jing)類的化學性(xing)質(zhi)(zhi)是(shi)不(bu)同的，芳香烴(jing)、環皖在(zai)(zai)常溫下均不(bu)易(yi)(yi)(yi)和(he)(he)空(kong)氣(qi)中(zhong)(zhong)氧(yang)氣(qi)反應。所以，主要由上述(shu)三種怪組成的汽(qi)油(you)的安(an)定(ding)(ding)性(xing)較好，汽(qi)油(you)也(ye)(ye)就在(zai)(zai)貯存(cun)和(he)(he)使用中(zhong)(zhong)不(bu)易(yi)(yi)(yi)變質(zhi)(zhi)。不(bu)飽和(he)(he)烴(jing)在(zai)(zai)常溫液相時，易(yi)(yi)(yi)與空(kong)氣(qi)中(zhong)(zhong)氧(yang)氣(qi)發生反應。所以，汽(qi)油(you)中(zhong)(zhong)如含有較多(duo)的不(bu)飽和(he)(he)烴(jing)，安(an)定(ding)(ding)性(xing)就差，生成膠質(zhi)(zhi)等而導致汽(qi)油(you)變質(zhi)(zhi)。另(ling)外汽(qi)油(you)中(zhong)(zhong)各(ge)種非烴(jing)類化合物也(ye)(ye)是(shi)引起汽(qi)油(you)氧(yang)化變質(zhi)(zhi)的重要因素。

直(zhi)餾(liu)汽(qi)(qi)油(you)中(zhong)不(bu)(bu)含不(bu)(bu)飽和(he)烴(jing)(jing)(jing)，其(qi)安(an)(an)定性(xing)(xing)很好；部分二次加(jia)(jia)工(gong)汽(qi)(qi)油(you)中(zhong)含有(you)(you)大(da)量不(bu)(bu)飽和(he)烴(jing)(jing)(jing)及非(fei)(fei)烴(jing)(jing)(jing)化(hua)(hua)合物(wu)(wu)，其(qi)安(an)(an)定性(xing)(xing)較(jiao)差。汽(qi)(qi)油(you)在貯(zhu)存(cun)和(he)使(shi)用中(zhong)，易變質(zhi)(zhi)生(sheng)膠(jiao)或生(sheng)成有(you)(you)機酸。特別是(shi)不(bu)(bu)飽和(he)短中(zhong)的(de)二烯烴(jing)(jing)(jing)最(zui)不(bu)(bu)安(an)(an)定，很容易氧化(hua)(hua)。盡管汽(qi)(qi)油(you)中(zhong)有(you)(you)時含有(you)(you)的(de)二烯烴(jing)(jing)(jing)量非(fei)(fei)常(chang)少，但卻能使(shi)汽(qi)(qi)油(you)的(de)安(an)(an)定性(xing)(xing)顯著變差。此外，汽(qi)(qi)油(you)中(zhong)的(de)硫、氮、氧的(de)非(fei)(fei)烴(jing)(jing)(jing)類化(hua)(hua)合物(wu)(wu)，對汽(qi)(qi)油(you)安(an)(an)定性(xing)(xing)都有(you)(you)不(bu)(bu)同(tong)程度的(de)影響。一(yi)般來(lai)說(shuo)，上述三(san)類非(fei)(fei)烴(jing)(jing)(jing)化(hua)(hua)合物(wu)(wu)含量越大(da)，其(qi)汽(qi)(qi)油(you)的(de)變質(zhi)(zhi)速(su)度越快(kuai)。值得注意的(de)是(shi)，汽(qi)(qi)油(you)氧化(hua)(hua)以(yi)后生(sheng)成膠(jiao)質(zhi)(zhi)，膠(jiao)質(zhi)(zhi)本身具有(you)(you)氧化(hua)(hua)催化(hua)(hua)作(zuo)用。也就是(shi)說(shuo)，膠(jiao)質(zhi)(zhi)會(hui)加(jia)(jia)速(su)汽(qi)(qi)油(you)的(de)氧化(hua)(hua)生(sheng)膠(jiao)。認識這一(yi)規律對汽(qi)(qi)油(you)的(de)使(shi)用有(you)(you)著重要意義，因(yin)為它告訴人(ren)們一(yi)旦發現汽(qi)(qi)油(you)開始生(sheng)膠(jiao)，在肢質(zhi)(zhi)急劇增(zeng)加(jia)(jia)前，就應及時安(an)(an)排使(shi)用以(yi)防(fang)止(zhi)引起汽(qi)(qi)油(you)嚴(yan)重變質(zhi)(zhi)。

外部條(tiao)件(jian)對(dui)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)安定性的(de)(de)影響外部條(tiao)件(jian)包括強度(du)(du)(du)(du)(du)、氧(yang)(yang)氣(qi)、水分及金屬催(cui)化(hua)(hua)等(deng)的(de)(de)影響。溫度(du)(du)(du)(du)(du)升高(gao)時(shi)，汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)速(su)度(du)(du)(du)(du)(du)加(jia)(jia)快。當(dang)環境溫度(du)(du)(du)(du)(du)在c-or時(shi)，汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)生膠的(de)(de)進程很慢；當(dang)環境溫度(du)(du)(du)(du)(du)高(gao)于15°e時(shi)，汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)生膠的(de)(de)進程加(jia)(jia)快；如(ru)(ru)環境溫度(du)(du)(du)(du)(du)高(gao)于35°e時(shi)，汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)生膠的(de)(de)進程將隨著貯(zhu)存(cun)時(shi)間的(de)(de)延長(chang)而(er)成倍增加(jia)(jia)。空氣(qi)與(yu)(yu)油(you)(you)(you)(you)(you)面的(de)(de)接觸(chu)量大(da)小及液面上空氣(qi)變(bian)換(huan)強度(du)(du)(du)(du)(du)對(dui)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)的(de)(de)安定性有(you)著很大(da)的(de)(de)影響。貯(zhu)油(you)(you)(you)(you)(you)容(rong)(rong)器(qi)中(zhong)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)裝(zhuang)滿的(de)(de)程度(du)(du)(du)(du)(du)，決定著汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)與(yu)(yu)空氣(qi)的(de)(de)接觸(chu)量。貯(zhu)油(you)(you)(you)(you)(you)容(rong)(rong)器(qi)是否密封(feng)，決定著汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)液面空氣(qi)的(de)(de)變(bian)換(huan)強度(du)(du)(du)(du)(du)。如(ru)(ru)空氣(qi)與(yu)(yu)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)液面接觸(chu)量大(da)且變(bian)換(huan)強度(du)(du)(du)(du)(du)大(da)，則(ze)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)的(de)(de)氧(yang)(yang)化(hua)(hua)變(bian)質(zhi)速(su)度(du)(du)(du)(du)(du)就會增大(da)。金屬對(dui)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)的(de)(de)氧(yang)(yang)化(hua)(hua)起(qi)著催(cui)化(hua)(hua)作(zuo)用(yong)(yong)，不(bu)同的(de)(de)金屬所起(qi)的(de)(de)催(cui)化(hua)(hua)作(zuo)用(yong)(yong)有(you)很大(da)差別。其中(zhong)銅(tong)的(de)(de)催(cui)化(hua)(hua)作(zuo)用(yong)(yong)強，其次是鉛。據實驗證(zheng)明，銅(tong)能使(shi)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)生臟的(de)(de)速(su)度(du)(du)(du)(du)(du)增加(jia)(jia)6倍。在汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)發動機燃料供給系(xi)中(zhong)，不(bu)僅有(you)銅(tong)(如(ru)(ru)銅(tong)濾網等(deng))，而(er)且有(you)鉛反(fan)如(ru)(ru)容(rong)(rong)器(qi)內壁鍍鉛層)。因(yin)(yin)而(er)，宜在汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)箱長(chang)期貯(zhu)存(cun)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)。因(yin)(yin)此，貯(zhu)存(cun)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)時(shi)，應(ying)盡(jin)(jin)量使(shi)用(yong)(yong)大(da)容(rong)(rong)器(qi)。少用(yong)(yong)或不(bu)用(yong)(yong)小油(you)(you)(you)(you)(you)桶或油(you)(you)(you)(you)(you)箱貯(zhu)油(you)(you)(you)(you)(you)。汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)中(zhong)含有(you)水分，也會使(shi)汽(qi)(qi)(qi)油(you)(you)(you)(you)(you)氧(yang)(yang)化(hua)(hua)速(su)度(du)(du)(du)(du)(du)加(jia)(jia)快。故應(ying)盡(jin)(jin)量避免水分進入油(you)(you)(you)(you)(you)中(zhong)。