Improving Selectivity in 2-Butyne-1,4-diol Hydrogenation using Biogenic Pt Catalysts
Improving Selectivity in 2-Butyne-1,4-diol Hydrogenation using Biogenic Pt Catalysts
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DOI：
10.1021/cs200572z
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发表时间：
2012-04-01
期刊：
影响因子：
12.9
通讯作者：
Wood, J.
中科院分区：
文献类型：
--
作者：
Bennett, J. A.;Attard, G. A.;Wood, J.
报道了标准的、在石墨负载的催化剂上的5wt%Pt和生物来源的Pt类似物两者对1，4-丁炔二醇氢化的选择性。在这两种情况下，使用循环伏安法确定台阶位点提供最大程度的氢化，并且故意阻断这些位点产生有利于1，4-丁炔二醇产物的显著选择性。对于5重量%的Pt/石墨催化剂，铋的不可逆吸附被用作台阶位点阻断剂。在细菌大肠杆菌内合成的生物Pt纳米颗粒（NPs）的情况下，观察到在化学清洁和随后从细菌支持物分离后留下的残留分子有机片段优先在缺陷位点处积累。这种现象促进了在炔氢化过程中对烯烃产物的选择性增加至高达1.4。当还研究了负载在细菌生物质上的铂的生物纳米颗粒时，发现它们也是活性和选择性的，尽管只有在颗粒被化学清洁并与生物质分离之后才优化对1，4-丁烯二醇的选择性。铋中毒的5%的铂在石墨上，虽然高度选择性，给出了一半的反应速率的生物对应物（20%和45%的转化率的起始材料分别在2小时后），但后者表现出较低的选择性丁烯二醇（分别为0.7和0.9）。因此，提出这样的生物源材料可能以与Lindlar型催化剂类似的方式潜在地起作用，Lindlar型催化剂广泛地用于有机合成中用于炔的选择性氢化，其中添加剂部分地使金属位点中毒，但不存在有毒重金属如铅的相关危害。
The selectivity towards 1,4-butynediol hydrogenation of both a standard,5 wt % Pt on graphite supported catalyst and a biogenic Pt analogue is reported, In both cases, it is determined using cyclic voltammetry that step sites afford the greatest extent of hydrogenation and that deliberate blocking of such sites gives rise to significant selectivity in favor of the 1,4-butenediol product. For the 5 wt % Pt/graphite catalyst, irreversible adsorption of bismuth was used as the step site blocking agent. In the case of the biogenic Pt nanoparticles (NPs) synthesized within the bacterium Escherichia coli, residual molecular organic fragments, left over after chemical cleaning and subsequent separation from the bacterial support, were observed to have accumulated preferentially at defect sites. This phenomenon facilitated an increase in selectivity toward alkenic products of up to 1.4 during hydrogenation of the alkyne. When biogenic NPs of platinum supported upon bacterial biomass were also investigated, they too were found to be active and selective although selectivity toward 1,4-butenediol was optimized only after the particles were chemically cleaned and separated from the biomass. Bi-poisoned 5% Pt on graphite, although highly selective, gave half the reaction rate of the biogenic counterpart (20% and 45% conversion of starting material respectively after 2 h), but the latter exhibited less selectivity for butenediol (0.7 and 0.9 respectively). It is proposed therefore that such biogenic materials may potentially act in a similar manner to Lindlar-type catalysts, used extensively in organic synthesis for selective hydrogenation of alkynes, in which an additive partially poisons metal sites but without the associated hazards of toxic heavy metals such as lead being present.