Dehydrogenation of Butanediol to GBL

[g_junkie]

thanks... i kinda figured that out after i posted,  i forgot that there was also water in the equation.

another newbie question...

whats the difference between the two types of copper chromite catalyts?? (rhod's and org synth's)

i realise that they use different chemicals/methods, but the end product is still copper chromite, right? (wrong, obviously, but why?)

[foxy2]

They will have different activities.

There is no way to know exactly how your catalyst will perform until you test it.  There are many many variables that can affect how your catalyst performs.
I hate my government, does this mean I'm a terrorist??

[Rhodium]

A novel route for synthesis of -butyrolactone through the coupling of hydrogenation and dehydrogenation
Yu-Lei Zhu, Hong-Wei Xiang, Gui-Sheng Wu, Liang Bai and Yong-Wang Li

J. Chem. Soc. Chem. Commun. (3), 254-255 (2002)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/ma-bdo2gbl.pdf)
DOI:

10.1039/b109658n

Abstract
 
A coupling process of the hydrogenation of maleic anhydride and the dehydrogenation of 1,4-butanediol has been invented for the synthesis of -butyrolactone over a Cu–Zn catalyst, realizing optimal hydrogen utilization and better energy efficiency.

[Rhodium]

Dehydrogenative cyclization of 1,4-butanediol over copper-based catalyst
Naoki Ichikawa, Satoshi Sato, Ryoji Takahashi, Toshiaki Sodesawa and Kanichiro Inui

Journal of Molecular Catalysis A: Chemical, 212(1-2) 197-203 (2004)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/14-bd.dehydrogenative.cyclization.pdf)
DOI:

10.1016/j.molcata.2003.10.028

Abstract
Synthesis of ?-butyrolactone (GBL) from 1,4-butanediol (BDO) over copper-based catalysts with ZnO, Al₂O₃ and ZrO₂ was investigated. Catalytic activity of copper was greatly affected by the additive oxides. The highest activity was obtained at a catalyst molar ratio of CuO:ZnO:ZrO₂:Al₂O₃=6:1:2:2. ZrO₂ showed the highest additive effect for the GBL synthesis with enhancing dehydrogenation ability of metallic Cu and enlarging Cu surface area. Al₂O₃ enlarged Cu surface area, whereas a large amount of tetrahydrofuran (THF) was formed over the acid sites of Al₂O₃ surface, and ZnO reduced the THF yield. The reaction pathway from BDO to GBL was also clarified: BDO was initially dehydrogenated to 4-hydroxybutanal, which was immediately hemiacetalized to 2-hydroxytetrahydrofuran, followed by the dehydrogenation to GBL over metallic Cu.