| US 7,495,138 B2 | ||
| Method for producing butadiene from n-butane | ||
| Sven Crone, Limburgerhof (Germany); Catharina Klanner, Mannheim (Germany); Götz-Peter Schindler, Mannheim (Germany); Mark Duda, Ludwigshafen (Germany); and Frieder Borgmeier, Mannheim (Germany) | ||
| Assigned to BASF Aktiengesellschaft, Ludwigshafen (Germany) | ||
| Appl. No. 11/722,278 PCT Filed Dec. 19, 2005, PCT No. PCT/EP2005/013659 § 371(c)(1), (2), (4) Date Jun. 20, 2007, PCT Pub. No. WO2006/066848, PCT Pub. Date Jun. 29, 2006. |
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| Claims priority of application No. 10 2004 061 514 (DE), filed on Dec. 21, 2004. | ||
| Prior Publication US 2008/0119680 A1, May 22, 2008 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. C07C 5/333 (2006.01) | ||
| U.S. Cl. 585—325 [585/616; 585/621; 585/628; 585/629] | 6 Claims |
| 1. A process for preparing butadiene from n-butane, comprising the steps of
A) providing a feed gas stream (a) comprising n-butane;
B) feeding said feed gas stream (a) into at least one first dehydrogenation zone and nonoxidatively, catalytically dehydrogenating
n-butane to obtain a gas stream (b) comprising n-butane, 1-butene, 2-butene, butadiene, and hydrogen, and optionally further
comprising carbon oxides and/or steam and/or inert gases;
C) feeding said gas stream (b) and an oxygenous gas into at least one second dehydrogenation zone and oxidatively dehydrogenating
1-butene and 2-butene to obtain a gas stream (c) comprising n-butane, butadiene, and hydrogen, and optionally further comprising
carbon oxides and/or inert gases;
D) compressing in at least one first compression stage and cooling said gas stream (c) to obtain at least one condensate stream
(d1) comprising water, and a gas stream (d2) comprising n-butane, butadiene, and hydrogen, and optionally further comprising carbon oxides and/or inert gases;
E) separating said gas stream (d2) by extractive distillation into a product stream (e1) consisting substantially of butadiene, and a stream (e2) comprising n-butane, hydrogen, and steam, and optionally further comprising carbon oxides and/or inert gases;
F) optionally compressing in at least one further compression stage and cooling said gas stream (e2) to obtain at least one condensate stream (f1) comprising n-butane and water, and a gas stream (f2) comprising n-butane and hydrogen, and optionally further comprising carbon oxides and/or inert gases, and optionally recycling
said at least one condensate stream (f1) into said first dehydrogenation zone;
G) separating said gas stream (f2) into a recycle stream (g1) comprising n-butane and an offgas stream (g2) comprising hydrogen, and optionally further comprising carbon oxides and/or inert gases, by contacting said gas stream (f2) with a high-boiling absorbent and subsequently desorbing the gas constituents dissolved in the absorbent.
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