Producing butadiene from butane

Claim 1

A METHOD OF PRODUCING BUTADIENE FROM NORMAL BUTANE WHICH INCLUDES THE STEPS OF SUBJECTING A GAS STREAM CONTAINING NORMAL BUTANE AS THE PRINCIPAL HYDROCARBON CONSTITUENT TO THE ACTION OF A DEHYDROGENATING CATALYST AT AN ELEVATED TEMPERATURE AND AT SUB-ATMOSPHERIC PRESSURE, RAPIDLY COOLING THE EFFLUENT FROM THE DEHYDROGENATION; REMOVING HYDROGEN FROM SUCH EFFLUENT; SUBJECTING THE HYDROGEN-FREED EFFLUENT TO A FIRST STAGE EXTRACTIVE DISTILLATION IN THE PRESENCE OF A LIQUID PARAFFIN OIL HAVING A BOILING POINT RANGE NOT LOWER TAHN ABOUT 155*F. NOR HIGHER THAN 345*F., SAID HYDROGEN-FREED EFFLUENT CONSISTING ESSENTIALLY OF A PRINCIPAL AMOUNT OF NORMAL BUTANE AND SIGNIFICANT AMOUNTS OF BUTADIENE, BUTENE-1, CIS-BUTENE-2 AND TRANS-BUTENE-2; WITHDRAWING AN OVERHEAD STREAM CONSISTING ESSENTIALLY OF SUBSTANTIALLY ALL OF THE BUTADIENE, MUCH OF THE BUTENE-1 AND A SIGNIFICANT AMOUNT OF NORMAL BUTANE; WITHDRAWING A BOTTOM STREAM AS A PARAFFIN OIL SOLUTION OF A MIXTURE CONSISTING ESSENTIALLY OF MOST OF THE NORMAL BUTANE, CIS-BUTANE-2 AND TRANS-BUTANE-2 AND SOME BUTENE-1; STRIPPING THE NORMAL BUTANE AND NORMAL BUTENES FROM THE PARAFFIN OIL AND RECYCLING THE NORMAL BUTANE AND NORMAL BUTENES FROM THE PARAFFIN OIL AND RECYCLING THE NORMAL BUTANE AND NORMAL BUTENES TO DEHYDROGENATION; SUBJECTING THE STREAM OF BUTADIENE, BUTENE-1 AND NORMAL BUTANE TO AN EXTRACTIVE DISTILLATION IN THE PRESENCE OF KETONE HAVING FROM THREE TO FIVE CARBON ATOMS, WHEREBY THE BUTENE-1 AND NORMAL BUTANE PASS OVERHEAD AND THE BUTADIENE IS ABSORBED IN THE KETONE; AND THEREAFTER RECOVERING THE BUTADIENE FROM THE KETONE.

Claim 2

A METHOD OF PRODUCING BUTADIENE FROM NORMAL BUTANE WHICH INCLUDES THE STEPS OF SUBJECTING A GAS STREAM CONTAINING NORMAL BUTANE AS THE PRINCIPAL HYDROCARBON CONSTITUENT TO THE ACTION OF A DEHYDROGENATING CATALYST AT AN ELEVATED TEMPERATURE AND AT SUB-ATMOSPHERIC PRESSURE, RAPIDLY COOLING THE EFFLUENT FROM THE DEHYDROGENATION; REMOVING HYDROGEN FROM SUCH EFFLUENT; SUBJECTING THE HYDROGEN-FREED EFFLUENT TO A FIRST STAGE EXTRACTIVE DISTILLATION IN THE PRESENCE OF A LIQUID PARAFFIN OIL HAVING A BOILING POINT RANGE NOT LOWER TAHN ABOUT 155*F. NOR HIGHER THAN 345*F., SAID HYDROGEN-FREED EFFLUENT CONSISTING ESSENTIALLY OF A PRINCIPAL AMOUNT OF NORMAL BUTANE AND SIGNIFICANT AMOUNTS OF BUTADIENE, BUTENE-1, CIS-BUTENE-2 AND TRANS-BUTENE-2; WITHDRAWING AN OVERHEAD STREAM CONSISTING ESSENTIALLY OF SUBSTANTIALLY ALL OF THE BUTADIENE, MUCH OF THE BUTENE-1 AND A SIGNIFICANT AMOUNT OF NORMAL BUTANE; WITHDRAWING A BOTTOM STREAM AS A PARAFFIN OIL SOLUTION OF A MIXTURE CONSISTING ESSENTIALLY OF MOST OF THE NORMAL BUTANE, CIS-BUTANE-2 AND TRANS-BUTANE-2 AND SOME BUTENE-1; STRIPPING THE NORMAL BUTANE AND NORMAL BUTENES FROM THE PARAFFIN OIL AND RECYCLING THE NORMAL BUTANE AND NORMAL BUTENES FROM THE PARAFFIN OIL AND RECYCLING THE NORMAL BUTANE AND NORMAL BUTENES TO DEHYDROGENATION; SUBJECTING THE STREAM OF BUTADIENE, BUTENE-1 AND NORMAL BUTANE TO AN EXTRACTIVE DISTILLATION IN THE PRESENCE OF KETONE HAVING FROM THREE TO FIVE CARBON ATOMS, WHEREBY THE BUTENE-1 AND NORMAL BUTANE PASS OVERHEAD AND THE BUTADIENE IS ABSORBED IN THE KETONE; AND THEREAFTER RECOVERING THE BUTADIENE FROM THE KETONE.