本文關(guān)鍵詞： 鉻釩雙中心 Phillips催化劑 乙烯聚合 烷基鋁 預(yù)還原　出處：《華東理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：聚乙烯是目前世界上應(yīng)用最廣泛,使用量最大的高分子聚合材料。雖然我國近年來聚乙烯總產(chǎn)能不斷提升,但是高附加值的高等級雙峰聚乙烯國內(nèi)產(chǎn)能依舊不足,大幅度依賴于進(jìn)口。而且隨著我國的經(jīng)濟(jì)不斷發(fā)展,雙峰聚乙烯的缺口也在進(jìn)一步擴(kuò)大。又由于近年來對節(jié)能減排的高要求,相比于現(xiàn)在主流的雙釜雙峰工藝,在單反應(yīng)器中直接生產(chǎn)雙峰聚乙烯的工藝擁有顯著優(yōu)勢,因此對應(yīng)催化劑的研發(fā)很重要。本文研究了之前在傳統(tǒng)Phillips鉻系催化劑基礎(chǔ)上開發(fā)的無機(jī)鉻釩雙中心催化劑在加壓條件下的聚合性能同時(shí)進(jìn)一步使用烷基鋁對無機(jī)鉻釩雙中心催化劑進(jìn)行預(yù)還原研究。通過對加壓條件下的乙烯均聚和與1-己烯的共聚行為及聚合產(chǎn)物比較,研究催化劑的制備方式,聚合溫度,釩含量,助催化劑濃度,催化劑種類和預(yù)還原劑種類等因素對催化性能的影響。實(shí)驗(yàn)結(jié)果表明,在實(shí)驗(yàn)的加壓條件下(0.4MPa),共浸漬和分步浸漬醋酸鉻和偏釩酸銨制備的雙中心催化劑在聚合活性和產(chǎn)物性能上并沒有顯著差異,考慮到更簡單的步驟和操作以及工業(yè)生產(chǎn)中較低的生產(chǎn)和設(shè)備費(fèi)用,共浸漬法是較優(yōu)的選擇。比較了共浸漬制備的不同釩金屬含量的雙中心催化劑的聚合活性,確定催化劑的最佳鉻釩比為1:1之后分別選用三乙基鋁(TEA)和三異丁基鋁(TIBA)作為助催化劑以及預(yù)還原劑對該雙中心催化劑進(jìn)行研究。以TEA與TIBA作為預(yù)還原劑的催化劑在聚合過程中助催化劑的用量大大降低。使用相同助催化劑時(shí),這兩種催化劑聚合活性的高低和變化趨勢基本一致,得到的產(chǎn)品分子量高低和分子量分布寬窄基本相同,說明TEA和TIBA的預(yù)還原效果相近。同時(shí)預(yù)還原后催化劑共聚產(chǎn)物的1-己烯插入率顯著提高,體現(xiàn)出催化劑預(yù)還原處理的獨(dú)特優(yōu)勢。
[Abstract]:Polyethylene is the most widely used and used polymer polymeric material in the world at present. Although the total production capacity of polyethylene in China has been increasing in recent years, the domestic production capacity of high-grade bimodal polyethylene with high added value is still insufficient. The gap of bimodal polyethylene is also expanding with the economic development of our country. And because of the high demand for energy saving and emission reduction in recent years, compared with the current mainstream double-pot bimodal process, The process of producing bimodal polyethylene directly in a single reactor has significant advantages. Therefore, the development of corresponding catalysts is very important. In this paper, the polymerization performance of inorganic chromium vanadium double center catalysts developed on the basis of traditional Phillips chromium system catalysts under pressure and the further use of alkyl aluminum to inorganic materials were studied. The prereduction of Cr-V double center catalyst was studied. The copolymerization behavior and polymerization products of ethylene homopolymer and 1-hexene under pressure were compared. The effects of preparation method, polymerization temperature, vanadium content, cocatalyst concentration, type of catalyst and type of prereductant on the catalytic performance were studied. Under the experimental pressure of 0.4MPA, there was no significant difference in the polymerization activity and the properties of the products prepared by co-impregnation and stepwise impregnation of chromium acetate and ammonium metavanadate. In view of simpler steps and operations and lower production and equipment costs in industrial production, co-impregnation is the preferred choice. The polymerization activity of bicentral catalysts with different vanadium metal contents prepared by co-impregnation is compared, When the optimum Cr / V ratio of the catalyst was 1: 1, triethylaluminotriethylaluminotrimethylammonium (TIBA) and triisobutyl aluminum (TIBA) were used as cocatalysts and pre-reductant respectively. The binocentral catalyst was studied with TEA and TIBA as prereductants. The amount of cocatalyst is greatly reduced during polymerization. When the same cocatalyst is used, The polymerization activity of the two catalysts is basically the same as the change trend, and the molecular weight and the molecular weight distribution of the products obtained are basically the same. The results show that the prereduction effect of TEA and TIBA is similar, and the insertion rate of 1-hexene in the copolymerized product of the catalyst after prereduction is improved significantly, which shows the unique advantage of the pre-reduction treatment of the catalyst.
【學(xué)位授予單位】：華東理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ325.12;O643.36

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本文編號：1514070