- 上一篇：基于HTRI的换热器优化设计
- 下一篇：金属离子负载凹凸棒土催化碱抽提木质素制备芳香醛的研究
摘 要： 木质纤维素中的木质素组分可通过氢化、热裂解、氧化等途径降解为有商业价值的有机小分子。酶解木质素没有经过药剂蒸煮的工艺过程，也没有经过萃取溶剂等化学药剂的破坏，基本保留了木质素的化学活性，是制备芳香醛的良好原料。凹凸棒土是一种层链状过渡结构的以含水富镁硅酸盐为主的黏土矿，具有广泛应用。本论文以稻草秸秆酶解渣为原料，借助凹凸棒土优良的物理化学性质和结构特点，分别采用 、 、 、 、 对凹凸棒土进行改性并作为催化剂催化木质素降解，以对羟基苯甲醛、香草醛及丁香醛的总产量为指标，比较改性前后及不同金属离子改性的凹凸棒土的催化效果，优选出较佳的催化剂及催化条件。实验结果表明：催化剂的加入能明显提高芳香醛的总产率，其中， 改性凹凸棒土催化剂催化效果最好。最佳的催化反应条件为：160 ℃、180 r/min、0.5 MPa、90 min，6 g酶解渣可制备芳香醛0.1666 g，其中对羟基苯甲醛0.01887 g，香草醛0.07021 g，丁香醛0.07752 g，得率分别为：0.83 %、3.11 %、3.43 %，总得率为7.37 %（对木质素）。70307
毕业论文关键词： 酶解渣，凹凸棒土，催化氧化降解，芳香醛，动力学
Abstract: Lignin in lignocellulose can be degraded by hydrogenation, thermal cracking or oxygen to get commerical organic small molecular. The enzymatic lignin without the pretreatment process of pharmaceutical cooking and the destruction of chemical agents such as extraction solvents basically keep the chemical activity of lignin. It is a good raw material for the preparation of aromatic aldehydes. Attapulgite is a kind of hydrated magnesium silicate based clay mineral with transition layer chain structure. In this paper, the enzymatic hydrolysis residue of rice straw was used as raw material and Attapulgite was modified by 、 、 、 、 and then used as catalyst to catalyze the degradation of lignin. The yield of p-hydroxybenzaldehyde, vanillaldehyde and syringaldehyde was calculated for catalyst selection and optimization of catalytic conditions. The results showed that the total yield of aromatic aldehydes could be improved by the addition of catalyst and was the best catalyst. The optimized catalytic reaction conditions are: 160 ℃、180 r/min、0.5 MPa、90 min under which the total aromatic aldehydes was 0.1666 g. P-hydroxybenzaldehyde was 0.01887g, vanillaldehyde was 0.07021g, syringaldehyde was 0.07752 g and the yield were 0.83 %、3.11 %、3.43 %, respectively.
Keywords：enzymatic hydrolysis residue,attapulgite,catalytic oxidation degradation,aromatic aldehyde, kinetics
目 录
1 绪论 4
1.1 木质素的来源和利用 4
1.1.1木质素的来源 4
1.1.2木质素的利用 4
1.2凹凸棒土 4
1.2.1凹凸棒土的物化性质 4
1.2.2凹凸棒土的催化作用 4
2 实验材料与步骤 5
2.1 实验材料与仪器 5
2.2 实验步骤 5
2.2.1酶解渣的测定 5
2.2.2 凹凸棒土的改性 7
2.2.3 催化剂优化实验 7
2.2.4 检测方法 9
3 结果与讨论 9
3.1色谱图分析处理 9