臺灣博碩士論文加值系統

本論文以CoAPO-5 (含鈷之五型磷鋁分子篩)為觸媒,探討以醋酸為溶劑
,氧氣為氧化劑,進行環己烷之液相氧化反應, 探討了觸媒用量、反應溫度
、反應壓力、數種羧酸溶劑對反應速率與產物分佈的影響. CoAPO-5有強
的氧化力,在不添加任何助催化劑或共反應物的情況下,即可催化環己烷進
行氧化反應,反應時並沒有觀察到明顯的誘導期存在. 主要的產物為環己
酮、環己醇與二質子酸(己二酸、戊二酸、丁二酸) 使用過的觸媒,仍擁有
原來的結構,因此可回收與再利用.以CoAPO-5催化環己烷之氧化反應途徑
有二:一是觸媒孔洞中活性座的催化作用;另一是溶液中自由基所引發,當
觸媒用量增加,經由活性座催化之反應速率變大,但溶液中自由基終止反應
速率變慢,使自由基濃度降低,所以觸媒用量增加,環己烷反應速率不再增
加.本實驗之溫度範圍為120讈-135讈之間,升高溫度,可提高環己烷之反應
速率,且環己酮與己二酸的產率亦隨之提高,但高溫時,加快己二酸之脫醯
基氧化反應,使丁二酸對己二酸的比值增高,降低己二酸之選擇率.溶劑在
本反應中扮演重要的角色,含有羧基的溶劑(乙酸、丙酸、正丁酸、正戊
酸)可有效地促進本氧化反應. 以上述羧酸為溶劑時求出環己烷的活化能
在39-40kcal/mole之間,顯示其在反應控制範圍而以丙酸為溶劑時,環己烷
有較高之轉化率.

A new photosesitive naphthoquinone diazide CoAPO-5 was found
to be an effect catalyst for the liquid oxidation of
cyclohexane with oxygen as the oxidatant and with glacial
acetic acid as the solvent. The effect of operating
parameters such as catalyst loading,temperature, oxygen
pressure and kinds of solvents on reaction rate and products
distribution were studied. CoAPO-5 has strong oxidizing
ability. It can catalyze the one-step liquid phase
oxidation of cyclohexane without adding any promoter and co-
reactant.Under our reaction conditions ,no induction period
was observed.The main products of reaction were
cyclohexanone, cyclohexanol and dibasic acid (adipic acid
,glutaric acid and succinic acid). The fractional yield of
dibasic acid ranges from 0.35 to 0.55,that of cyclohexanone
is 0.3 to 0.45 ,and cyclohexanol is 0.08 to 0.15. This
catalyst can be reused several times,because it still has the
structure of CoAPO-5 after reaction. Solvent plays an
important role in these reaction system. Those with a carboxyl
group such as acetic acid, propionic acid, n-butyric acid and
n-pentanonic acid can effectively promotethese oxidation
reactions. Conversion of cyclohexane is higher when
propionic acid is used as solvent.