| 摘要: | 摘要 本研究以含浸-化學還原法製備負載式CuB/SiO2系列觸媒，並添加不同金屬(鉻、釷及鎢)促進劑，藉由丁醛液相氫化為模式反應，尋找負載式CuB/SiO2觸媒製備之最適條件，並探討糠醛(含呋喃環外羰基鍵及環內烯基鍵)、巴豆醛(含共軛烯基鍵-羰基鍵)及檸檬醛(含共軛烯基鍵-羰基鍵及一孤立烯基鍵)的選擇性氫化催化性質，並與非負載式CuB觸媒、傳統Cu/SiO2觸媒及商用銅-鉻觸媒做一比較。 以含浸-化學還原法製備負載式CuB/SiO2觸媒，最適條件為，以硝酸銅為先驅鹽，以臨溼含浸法含浸於SiO2擔體，經100℃乾燥過夜與140℃煅燒後，將硼氫化鈉以6ml/min及B/Cu=3(莫耳比)滴定還原製得。 以含浸-化學還原法製備負載式CuB/SiO2觸媒，硼的含量高於未負載CuB觸媒，且隨負載量增加而降低。CuB可以均勻負載於SiO2擔體上，未明顯阻塞擔體孔洞。不同其它金屬-硼觸媒的非晶態，CuB/SiO2屬晶態觸媒，CuB負載於SiO2擔體後熱穩定度可明顯提升，且引入促進劑鉻及釷不但能增加觸媒分散度亦能更進ㄧ步提升觸媒的穩定度。 CuB/SiO2觸媒在液相氫化反應，不同負載量觸媒中以10%CuB/SiO2觸媒氫化活性最佳，且活性遠優於未負載的CuB觸媒及傳統式CuB/SiO2，添加鉻後其活性可媲美商用銅-鉻觸媒。在糠醛氫化反應中，主要產物為氫化羰基得糠醇，幾乎無其他副產物。在巴豆醛氫化反應中，反應前三小時的主要產物為氫化烯基得丁醛(選擇 率約80%)，隨反應時間丁醛會繼續氫化成丁醇。在檸檬醛氫化反應中，由於檸檬醛有立體阻礙的影響，主產物為氫化羰基得橙花醇(選擇率約65%)，其餘為香茅醛，隨反應時間香茅醛會繼續氫化成香茅醇。 In our study ,the catalysts of CuB/SiO2 and Me-CuB/SiO2(Me: Cr, Th, W) were prepared by a reductive-impregnation method. Using butyradehyde liquid hydrogenation reaction searched suitable preparation conditions . Then, we probed to the catalysis property in selectivity hydrogenation of furfural, crotonaldehyde and citral ,and compared with CuB, Cu/SiO2 and Copper chromite. The suitable preparation conditions were base on the conversions, using copper nitrate precursor salt impregnated into SiO2 and furthermore passing through 100℃drying and 140℃calcination, the feeding rate of NaBH4 solusion about 6 ml/min and the copper salt/ NaBH4ratio of 1/3 was the optimal choices for preparing CuB/SiO2 and Me-CuB/SiO2 catalysts. In catalyst characterization, these borons of CuB/SiO2 catalyst were containing more than non-surport catalyst. CuB could loaded averagely above SiO2 ,and then didn’t block pore of surport. Diference from other amorphous Me-B catalysts, CuB/SiO2 is crystal. Passing through surporting, CuB could promote its stability of heat ,and doppimgTh and Cr could furthermore upgrate its dispersion and stability. In activity measurement, 10% loading had best activity in liquid hydrogenation and was better than CuB, Cu/SiO2, by dopping Cr, its activity could to compare favorably with copper chromite. In furfural hydrogenation reaction, major product was reduced the carbonyl bond to produce furfuryl alcohol and no residue was found. In crotonaldehyde hydrogenation reaction, the major product in 3 h was reduced conjugated C=C bond to produce butyraldehyde, with reaction time increasing, butyradehyde could proceed to butanol. In citral hydrogenation reaction, owing to steric hiderence effect, the major product was reduced the carbonyl bond to produce Nerol and Geraniol, and others were citronellal, with reaction time increasing, citronellal could proceed to citronellol. |
