close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3080445

код для вставки
March 5, 1963
M. NAGER
3,080,435
DEHYDROGENATION PROCESS
Filed July 18, 1960
PRODUCT + H20
\2
I2
'
4J-_- MOLTEN SALT
FEED
(IODIDE+
|,:-—°—2-> SUSPENDED
3T-P OXIDE )
FIG. I
02
IODINE
\lz
REGENERATOR
H o
a
IODINE
SCAVENGER
\9
H 0 ‘AND RESIDUAL
8\_ 2
IODINE s p ECIE_S
SEPARATOR
ORGAN‘C
-———7—> PRODUCT
\6
7
RECOVERY
5\REACTOR
EFFLUENT
4
\.
l2
7
l
ORGANIC
,-——>
FEED
v
MOLTEN
SALT
\2
REACTOR
37 02'
INVENTOR:
'
HQ 2
MAXWELL NAGER
BY; dag/MM
HIS ATTORNEY/
assess
Patented Mar. 5, 1963
2
the process steps of the present invention in one alterna
3,689,435
tive form.
DEHYDRD-GENATHQN PROCE§S
Maxwell Nager, Pasadena, Tex., assignor to Shell Oil
_
_
Now, in accordance with the present invention, an un
proved process has been provided for the dehydrogenation
of organic compounds containing CH groups by int1mately
contacting the organic compound in admixture with free
Company, New York, N.Y., a corporation of Delaware
Fiied July 18, 196i}, Ser. No. 43,647
12 Claims. (Cl. 26tl—673.5)
oxgen with a molten metal iodide at an elevated tem
perature at which oxygen liberates free iodine from the
metal iodide, the proportion of oxygen being at least
dehydrogenation of organic compounds. It relates more
particularly to the dehydrogenation of hydrocarbons to less 10 su?icient to liberate an amount of iodine from the metal
This invention relates to an improved process for the
iodide to effect dehydrogenation of the added organic
compound. The process is advantageously carried out
by passing the organic compound in a gaseous state and
Various methods have been proposed for the dehydro
free oxygen (admixed with the organic compound or
genation of organic compounds, including simply thermal
dehydrogenation and catalytic dehydrogenation as well 15 separately) through a hot body of the molten metal iodide;
the molten metal iodide preferably also contains, ?nely
as chemical reaction with agents which cleave carbon-to
dispersed therein, either homogeneously as a solution
hydrogen bonds and combine with the hydrogen under
therewith or heterogeneously as a ?nely dispersed liquid
the reaction conditions to form inorganic stable atom-to
or solid therein, at least a substantial proportion of a metal
hydrogen bonds, such as oxygen and chlorine. In some
instances of chemical or chemical and catalytic dehydro 20 oxide which is reactive with hydrogen iodide.
The metal iodide may be a single salt or a mixture of two
genation, using oxygen as the dehydrogenating agent oxy
or more metal iodides. The metal iodide may be used in
genation of the organic residue accompanies the dehydro
admixture with other molten salts, which, of course, should
genation, as in the recently announced process of reacting
saturated hydrocarbons, i.e., hydrocarbons having a higher
carbon-to-hydrogen ratio.
be inert or non-reactive to the reactants and the metal
propene with oxygen in contact with a bismuth molybdate
25 iodide.
catalyst to form propenal (acrolein).
Although the exact nature of the reactions involved is
Among recent developments which have been made in
not completely understood, the results of studies of the
dehydrogenating organic compounds, there is one in which
e?ect of varying di?erent variables, such as contact time,
a mixture of the compound and a substantial proportion
relative proportion of oxygen, temperature, relative
of elemental iodine in vapor phase is exposed to a tem
perature above 300° C. for a relatively short time. British 30 amounts of metal oxide used, etc., indicate that three dif
ferent reactions are involved in the process: (a) reaction
Patent 793,214 describes this class of reaction. These
of oxygen with the metal iodide to form free iodine and
dehydrogenation reactions include, for example, the con
the corresponding metal oxide; ([1) reaction of the liberat
version of para?ins to ole?ns and diole?ns, of ole?ns to
are converted to other compounds having a higher carbon
ed free iodine with the dehydrogenatable organic substance
to form hydrogen iodide and dehydrogenated organic sub
stance, and (c) reaction of the hydrogen iodide with metal
to-hydrogen ratio, with the simultaneous conversion of
the iodine to hydrogen iodide. These reactions proceed
generally with high e?iciency at the preferred reaction
oxide to form metal iodide and water. Since the (b)
reaction may be controlled in part by the concentration of
free iodine, and this is dependent upon the proportion of
adding oxygen together with the iodine to the dehydro
genation and the following formation of hydrogen iodide.
diole?ns, of certain paraihns to aromatics (dehydrocy~
clization) and other reactions in which organic compounds
conditions. It is possible to reduce materially the amount 40 oxygen, it is seen that the extent of the (b) reaction may
be controlled indirectly by varying the proportion of
of elemental iodine that must be charged for the organic
oxygen delivered to the molten iodide mass. The propor
reactant by reconverting some of the hydrogen iodide to
tion of oxygen added largely determines the course and
elemental iodine while it is present in the reaction mixture
extent of the other reactions including the formation of
at reaction conditions. For this purpose, it has been pro
posed to improve iodine utilization in such a process by 45 metal oxide, the release of iodine, the degree of dehydro
A number of advantages are obtained by the present
genation reaction zone to convert formed hydrogen iodine
process. Thus, whereas the iodinative dehydrogenation
is endothermic, and when practiced independently re
quires that the heat of reaction be supplied from; another
to iodine and water. However, although the e?iciency of
iodine utility is increased, the effluent mixture still con
tains iodine species which causes undesirable reactions
unless the eiiluent mixture is rapidly quenched and re
source, the overall heat of the reactions involved in this
process is exothermic, thereby avoiding the necessity of
quires special handling techniques.
heat transfer to the reaction zone.
It is the primary object of this invention to provide an
Moreover, since the
iodinative dehydrogenation reaction alone is equilibrium
limited, rapid reaction of the hydrogen iodide with the
improved process for the dehydrogenation of organic
substances, and especially iodine-effected dehydrogenation,
including dehydrocyclization and dehydroisomerization in
metal oxide shifts the reaction to a higher dehydrogena
tion conversion of the organic substance; this is particu
larly valuable for the dehydrogenation of light hydro
of the invention to provide a process of dehydrogenation
carbons wherein the tempera-tures normally required for
with iodine wherein the use of a quench following the re
high equilibrium conversion are also conducive to ther
action is minimized or avoided and wherein the amount 60
mal cracking. Furthermore, the maintenance of only a
of iodine species in the reaction ef?uent is minimized or
very low concentration of hydrogen iodide in the reac
substantially avoided. It is a further object of the inven
tion zone eliminates, or substantially eliminates, the ne
addition to simple dehydrogenation. It is another object
tion to provide such a process promoting a desirable shift
in the equilibrium of the reaction mixture. These objects
will be better understood and others will become ap
65
cessity for a rapid quench of the reactor effluent as well
as the recovery and recycling of the relatively large
amounts of iodine species normally required. Still fur
parent from the description of the invention which will be
made with reference to the accompanying drawing, where
ther, the molten salt mass together with the in situ for
mation of the iodine, provides for a highly eilective con
in:
tacting of the iodine and the organic substance, for
FIGURE I is a schematic representation of the process
steps of the invention in its simplest form, and
FIGURE II is a simpli?ed schematic representation of
quickly bringing the organic substance to the desired re
action temperature, and provides an excellent heat ‘trans
fer medium for transferring the excess heat ‘from the re
3
8,080,435
4
action zone. Of course, ixtures of salts may be uti
lized which are either all in the molten state or wherein
at least one is molten and the remainder are suspended
in the molten plasma. In any case, the amount of solid
or molten iodide present in the molten sal-t mixture is
su?icient to provide, when oxidized, the necessary amount
of iodine for reaction and also metallic oxide suf?cient
to substantially completely remove hydrogen iodide from
the reaction mixture as it is formed.
a problem. Liquid-gas contacting is extremely e?icient.
Melting points and vapor pressures of iodides are no
longer limiting. In a molten salt system substantially all
of the oxide and iodide is available for reaction.
Fi
nally, if the ceramic lining of the reactor should crack,
molten salt would leak in, solidifying and sealing the
crack thus preventing corrosive vapors from attacking the
metal outer shell.
If the iodides or oxides (or their equivalents) exhibit
Iodides and corresponding oxides useful in the proc 10 high vapor pressures at the temperatures utilized, suitable
ess of the invention are particularly those which meet
two criteria: (1) iodides which are chemically and ther
recovery or condensing systems are desirable.
mally stable but also convertible at the dehydrogenation
the drawing as follows: FIGURE I represents a most
temperature (especially 200~1000° C.) to the corre
sponding oxide by reaction with oxygen and (2) Cor
responding oxides which form iodides by reaction with
The invention will be best understood by reference to
elementary and simple arrangement for use of the in
15 vention. According to FIGURE I, a feed is led by means
of line 1 into a reactor 2 which is at least partially
?lled with a molten salt comprising essentially a metallic
These include especially arsenic, antimony, lead, zinc,
iodide. Oxygen is injected by means of line 3 into the
cadmium, copper, nickel, cobalt, manganese, calcium,
reactor 2 for the primary purpose of converting at least
lithium and cerium and rare earth metals. With the ad 20 part of the molten iodide into a suspended metallic ox
ditional injection of carbon dioxide (plus oxygen) cer
ide. Alternately, the oxygen can be admixed with the
tain carbonate-iodide fused salt systems may be employed.
feed in line 1 rather than injected separately into the ‘re
These include particularly barium or sodium carbonates
actor. The temperature of the reactor is at least 200° C.
and their corresponding iodides. The formation or addi
so as to enable dehydrogenation to occur by reaction of
tional injection of water makes possible the use of cer 25 the feed with iodine which is released upon conversion
tain regeneratable hydroxides, such as lithium hydrox
of the metallic iodide into the corresponding metallic
ide. Whenever reference is made in the speci?cation
oxide. Supplementary proportions of iodine species may
and claims to “oxide” it will be understood that car
be injected by means of line 4 to make up for any losses
bonates and hydroxides are included as long as they meet
in iodine content which may occur. The ef?uent which
the two criteria of ready regeneration under the condi 30 is removed by means of line 5 from reactor 2 comprises
tions of dehydrogenation. I-odides are preferably present
the 'dehydrogenated feed and water with substantially no
in substantial excess, i.e., su-?‘icient to provide a molten
effective amount of iodine species.
iodine species at the dehydrogenation tern eraiture.
salt phase in which dehydrogenation may take place and
FIGURE 11 shows a somewhat more elaborate arrange
at the same time su?icient to provide a portion to be
ment of apparatus employing the same'reactor 2, the feed
converted by oxidation to the corresponding metallic ox 35 line 1, the oxygen injection line 3 and the iodine injection
ide. It is preferred that the mol proportion of the molten
line 4 as well as the reactor e?iuent line 5. According'to
iodide to hydrocarbon in the reactor at any given time
FIGURE II, the reactor ef?uent is sent to a separator 6
is maintained between about 2:1 and 100:1.
wherein the organic product is separated and sent to
According to the process of the invention, dehydrogena
recovery by means of line 7. The remaining aqueous
tion of the hydrocarbon in the molten salt environment
is effected by the injection of oxygen to such an extent
that su?i-cient iodine is regenerated from metal iodide to
effect dehydrogenation of added organic compound and
phase comprises principally Water and any residual iodine
species which may have escaped being trapped by the
hydrogen acceptor in the molten salt reactor 2. This
mixture is sent by means of line 8 to an iodine scavenger
at the same time form an oxide in an amount sui?icient
area 9 wherein the iodine acceptor removes substantially
to maintain the hydrogen iodide content of the system 45 all ofthe iodine species from the system and rejects water‘
at an extremely low level (i.e., by reaction of HI with
by means of line 10. The iodine scavenger may be such
the metal oxide). By this is meant, a system in which
a material as a metallic oxide which performs the same
the hydrogen iodide concentration is below a point at
function that it did in the molten salt reactor or it may
which it‘ adversely affects the desirable reaction com
be a reactive metal such as copper which immediately
ponents. Usually, the system is such that hydrogen 50 reacts with iodine species to form various copper iodides.
iodide exists only momentarily, being converted almost
immediately to metal iodide.
These are then removed by means of line 11 to an iodine
For the, most part, the
regenerator 12 wherein elemental iodine is regenerated
metallic oxides are solids and hence will exist as sus
and recycled to the molten salt reactor by means o-f-re
pensions in the molten salt environment. It is preferred
cycle line 4.
55
that the mol proportion of metallic oxide to metallic
In still another system, the dehydrogenation zone (con
iodide be maintained between about 0.01:1 and about
tact of feed and iodine) may be segregated from the ‘re
0.5 :1 ‘so as to insure the substantially immediate con~
version of hydrogen iodide (formed in the dehydrogena
tion reaction) to metallic iodide while still maintaining
generation zone (contact of dehydrogenated product and
iodine species with molten iodide and oxygen), the iodine
formed
in the latter zone being cycled back to the de
60 hydrogenation zone.
an essentially ?uid system.
The proportion of oxygen injected into the'system to
In extensive studies it has been determined that the
form the optimum amount of metallic oxide may vary
following hydrocarbons are iodine-reactive and are, at
from about 0.1 mole of oxygen per mol of hydrocarbon
proper reaction conditions, converted by contact with ele
to even as much as 100 mols of oxygen per mol of hy
mental iodine into the indicated more unsaturated reac
drocarbon. The proportion of oxygen employed is gov 65 tion products, generally in reactions of very high selec
erned at least in part by the results desired. For ex~
ample, if the feed is a gasoline and it is desired to con
tivity.
Hydroaromatic alicyclic compounds can be converted
to the corresponding aromatic compounds by dehydro
70 genation. Compounds containing an aliphatic chain of at.
gen may be used in the pure state or admixed with inert
least 6 non-quaternary carbon atoms can be converted to
vert only a limited proportion thereof to aromatics, then
the oxygen input is correspondingly restricted. The oxy
diluents such as nitrogen or steam. Air may be utilized.
The use of such a system provides va number of ad
vantages over the use of the corresponding solid'metallic
aromatics by dehydrocyclization, as can cyclic com
pounds having an aliphatic chain or aliphatic chains
capable of closing a ring of 6 carbon atoms. Compounds
oxides and iodides. Thus, attrition of solids is no longer 75 having an’ aliphatic chain cfu2 to 5 vnon-quatertlarycan
3,080,436
5
6
diene-l,3. Other methyl substituted cyclopentanes and
cyclopentenes are similarly converted.
(l0) Hydroaromatics to corresponding aromatics.
For example: Cyclohexane to benzene. Methylcyclo
bon atoms and compounds having a ring of 5 carbon
atoms can be converted by dehydrogenation into com
pounds having a greater number of carbon-to-carbon
double bonds. Certain more saturated compounds may
hexane to toluene.
also be converted to compounds having acetylenic triple
bonds, e.g. ethane or ethene to acetylene. Compounds
which have an aliphatic chain of at least 5 or 4 carbon
atoms, including respectively, 1 or 2 quaternary carbon
Ethylcyclohex-ane to ethylbenzene.
1,2-dimethylcyclohexane to xylene.
hexane to m-xylene.
1,3-dimethylcyclo
1,4-dimethylcyclohexane to p
xylene.
(11) Aromatics with alkyl side chains of 2 or more
atoms and which have no chain of 6 non-quaternary car
bon atoms are converted, by reaction including con 10 carbon atoms, especially those with 2 to 3 carbon atoms
in the chain, to aromatics having unsaturated side chains.
version of a quaternary to a non-quaternary carbon atom,
For example: Ethylbenzene to styrene. n-Propylbenzene
to beta~methyl-styrene. Isopropylbenzene to alpha
into different compounds having the same carbon num
ber as the feed, followed, if residence time is su?icient,
methyl-styrene.
by conversion of the latter compounds in accordance ‘with
their new structure, eg, into aromatics.
15
( 12) Suitable organic compounds may be treated ac
cording to the process of this invention. These include
The invention is, for example, particularly suitable for
alcohols, iodides, acids, nitriles, amines, etc. Species ex
the following conversion reactions:
emplifying these are isopropyl alcohol, propionitrile, oc
(1) Methane to ethylene and acetylene (by coupling).
t-adecyl amine, butyric acid, hexyl iodide, etc.
(2) Ethane to ethylene and acetylene.
Although the reaction of hydrocarbons with iodine is
20
\( 3) Ethylene to acetylene.
highly selective, differences have been observed between
(4) Propane to propylene, methylacetylene or allene.
various hydrocarbons, both in the rate of reaction and in
(5) Propane or propylene to benzene (by coupling
‘the selectivity to a particular compound. Thus, the rate
at which ole?ns are converted to compounds having a
and cyclization).
(6) Aliphatic compounds having from 4 to 5 contigu 25 higher degree of unsaturation, either diole?ns or other
ous non-quaternary carbon atoms in a chain to the cor
ole?nic compounds or aromatics, is considerably greater,
responding ole?ns and diole?ns, and particularly con
jugated diole?ns. This includes the following conver
often by a factor of 10 or more, than the rate of reaction
of para?ins of the identical skeleton at otherwise equal
conditions. It has also been found that the ideal length
of the chain of contiguous non-quaternary carbon atoms
in the aromatization of aliphatic compounds by dehydro
sions: n-Butane to l-butene, Z-butene and 1,3-butadiene;
l-butene or 2-butene to 1,3-butadiene; n-pentane to 1
pentene, 2-pentene and 1,3-pentadiene, l-pentene or 2
pentene to 1,3-pentadiene isopentane to S-mcthyl-l-bu
tene, 3-methyl-2-butene, 2~methyl-l-butene and isoprene.
(7) Aliphatic hydrocarbons having a chain of at least
6 contiguous non-quaternary carbon atoms and having 35
from 6 to 16 carbon atoms per molecule to aromatic
hydrocarbons. This includes the following conversions:
n-Hexane to benzene. Straight chain hexenes to benzene.
n-Hepta-ne to toluene and a small amount of benzene.
Straight chain heptenes to toluene and a small amount
of benzene. Monomethylhexanes to toluene. Mono
methyihexenes to toluene. n-Octane to aromatics pre
dominating in ethylbenzene and ortho-xylene. Straight
cyclization is from 6 to 7 carbon atoms for the most
e?icient conversion of aromatics. When longer chains
are aromatized the product contains not only aromatics
of the same number of carbon atoms but also appreciable
‘amounts of lower aromatics, formed by splitting o?‘ of
~short: fragments, e.g., methyl or ethyl groups. Except for
this latter effect of losing short fragments from aromatics,
the reactions of the present invention are highly selective
in producing a product having the same number of carbon
atoms as the charge hydrocarbon. Thus, the present in
vention is not concerned with promotion of the cracking
of hydrocarbons.
chain octenes to aromatics predominating in ethylbenzene
Of course, the dehydrogenation may be applied not only
DMH, 2,4-DMH, 2,5-DMH and 3,4-DMH, as well as
pure iodine-reactive hydrocarbon in admixture with inert
and orthoxylenes. Monomethylheptanes to monometh 45 to single compounds but, more usually to technical mix~
'tures thereof. Reforming operations, involving various
ylheptenes to aromatics predominating in xylenes. Di
gasolines, are contemplated.
rnethylhexanes (DMH) other than geminal, i.e., 2,3
corresponding monooie?ns, to xylenes; thus: 2,3-DMH
and 3,4-DMH give ortho-xylene; 2,4-DMH give metaxyl
The feed charged to the reaction mixture may be a
50 compounds.
An inert compound, for example, nitrogen
or steam, which is not converted under the conditions
of this invention.
The oxygen may be employed as pure oxygen gas or
diluted, e.g., air or oxygen diluted with helium or other
one and 2,5-DMH gives para-xylene. C10 saturates con
taining no quaternary carbon atoms, and the correspond
ing ole?ns, to substituted monocyclic aromatics with pre-.
dominantly saturated side chains. The following are
gases.
illustrative: n-Decane to n-butylbenzene, propyltoluene, 55 inert
The present invention can be carried out by passing a
diethylbenzene, propylbenzene, ethylbenzene, toluene and
vaporized mixture of a hydrocarbon feed with at least
benzene plus some of the corresponding compounds with
0.1 mol (preferably at least 0.5 mol) of elemental iodine
side chain unsaturation. S-methyl-nonane to n-butyl
per mol of hydrocarbon (preferably obtained internally
benzene, propyltoluene, l,4-dirnethyl-Z-ethylbenzene (2
by regeneration from the metallic iodide supplemented if
ethyl-p-xylene), m-ethyltoluene, p-xylene and toluene 60 necessary from external sources to make up for any losses)
plus some of the corresponding compounds with side
chain unsaturation.
(8) Aliphatic hydrocarbons having from 6 to 16 car
through a molten salt environment reaction zone main
tained at a temperature above about 200° C. and pref
erably between about 450 and 800° C. Simultaneously
bon atoms and having quaternary carbon atoms can also
65 a gas containing oxygen such as pure oxygen or air is
be converted to aromatics. Especially suitable are 2,2,4
‘added to the reaction zone in admixture with feed or at
trimethylpentane and 2,4,4-trimethylpentenes which are
one or more spaced points in the molten salt reaction
zone. The nominal residence time of the feed compound
converted to xylenes, predominantly p-xylene.
in the molten salt reaction zone is in the range from
(9) Non-hydroatromatic cycloparaf?ns and cycloole
fins to corresponding cycloole?ns and cyclodiole?ns. For 70 about 0.01 to 60 seconds.
The “Active iodine species” refers to the following com
example: Cyclopentane to cyclopentene and cyclopenta
pounds in the reaction mixture: iodine, hydrogen iodide
diene-l,3. Cyclopentene to cyclopentadiene-l,3. Meth- 4
and compounds which liberate either iodine or hydrogen
_ylcyclopentane to l-methyl-cyclopentene, 3-methylcyclo
pentene, 4-methylcyclopentene, l-methylcyclopentadiene-> iodide at reaction temperatures. The amount of iodine
1,3,Z-methyl-cyclopentadiene-1,3 and S-methylcyclopenta 76 employed may, for convenience, be expressed in theories,
13,080,435
8
7
.1 'f‘theory” is the theoretically required amount of ‘iodine,
from the "reactor.
determined by the stoichiometry of the reaction, to con
percent excess iodine loss was held to a minimum.
vert one unit of feed compound to the favored dehydro
‘genati-on product. For example, to convert one gram
TABLE 3
Dehydrogenation of Ethane in a Riser Reactor
molecular weight of normal hexane to benzene required
8 gram atomic weights or 4 gram molecular weights of
elemental :iodine.
The number of theories of iodine
Reactor type
species present in the reaction zone of the present inven-
_
'
'
p mp
_
preferably from 0.1 to 0.8 theories exclusive of iodine 10
'
Riser u
“
Salt
L11
Load,g ____________________________ __
Present initheform of metallic iodides. The invention 1s
1
Rice]:
"""""""""""""""" “
tion aisrsui-tably in the range of from
about. ‘0.05 to. 1.5,
.
.
further illustrated by the following examples:
By’ increasing the ethane ‘to a live
X1C§f6é;1--é---
Hy<1§0c§b0€ffgg¢1/____
'
ee
Table 1, which follows, illustrates the results obtained
P01,
“155
300
5125C?)
PbO
Tgsthanef
to e. cc. min.
Ah, me, m/mm _____________ __
the dehydrogenation of propane to form propylene. It 15
genlgflwture. F-- ---_ .. 1,133 1,12% 1,100
.Will ‘be :seen according to the table that conversions in
Products,’pereéiil'??biisis'fééiféniéiiei“
11%
I
.
the orderof 50-80 percent-were obtained with arselectivity
5
no
70
m
Excess ethane, percent m__
125
5
130
by the use of a number of ditferent metallic iodides 1n
70
-33
O
eth
9%.? 5%.: 81.2
to .propylenes of 70-96 percent.
2.5
41.4.
7.6
0.3
0.2
0.0
0.3
0.3
_____ __
TABLE 1
20
Dehydrogenatzon
of Propane
Y
.
elt-Pot- RBGCZOI'
‘
Cumula‘
Flow
rate,
CcJmin, Reactor
‘air
‘temp,
propane
51.;
40.3
0.2
1.1
_
Salt .
'Salt load,g.
00
tive
run
° F.
'
‘
Con-
selec-
0.7
0.3
3.7
Conversion, percent r11_
v98
59
92
Selectivity, percent In
96
90
01
91
HI loss,° percentm._
0.10
0.10
0. 08
0.04
Oxygen used, percent
100
100
91
07
version. tlrity, 25
percent percent
time,
min.
m.
2-4
..... .
2.3
60
'
m.
I 155 g. Lil-31120 dehydrates to 111 g. LiI.
b 25 g. LiOH was used which equals 15.6 g. L120.
‘1 HI loss is based on the oxygen input rate. Accuracy of this determi
.
MI...
.
34 _
850
5
79
__________________________________ __
20.
3,11
2?
g? 30
165
‘62
95
when using a mixture of molten lithium iodide in which
is suspended lithium oxide. According to this table it
,
PM’;
nation is 10.02%.
50
_
950
228
g8
3g
1,000
60
52
91
will be seen that a study was made at 1050" F. using
ZnIb -"".;§f-""§5f """ "55.-
l'ggg,
?g
g2
23
various air/butane ratios. At the stoichiometric ratio
104v
4s
97 35 (5 volumes of air per volume of butane) a conversion
100
20
50
Table 4, which follows, illustrates the results obtained
,
can-
30.
88
20;
50
900
.
v
,
of 75 percent was obtained with butadiene and mixed
Table 2 illustrates the results obtained by the dehydro-
buts/lens: selectivities of 63 percent and 5 Percent, respec
.genation ofethane usingthree.differentsaltoxide systems.
Againit will be seen that. high conversions and highselec-
tlvely. Various other products such as ethylene, pro
Pylene, cyclohexene, b?nzene, 101116116, etc” accounted for
.tivityto ethylene were obtained,
40 the remaining oxygen fed, since oxygen utilization was
AccordingIto-.the.<results,given.in Table 2, all three of
100 percent. By increasing the air/butane ratio to 6,
the‘iodidestested exhibitedanincrease in selectivity with
increased conversions.
conversion was increased to 84 Percent and ‘at a ratio'of
7 conversion was 92 percent. Butadiene selectivity in
TABLE 2
Dehydrogenation of Ethane
Reactor type ......... -, ............. --
Melt-pot
Salt; _________________________________ -_
L0ad,'g_____
'
LlI
'
PbT.
60.0 .
s
Feed rate, ccJLuin
‘Air rate, ccJmiu .......... .-
our.
40.0
Hydrocarbon feed-..
<—-~40.0
Ethan“
‘—
20
_
\
_50
Cumulative run-tlrne,mln__
60-120
Reactor temperature,‘o F ........... _; 1,000
Products, percent 111., basis teed ethane:
ethane ________________________ __
180
1,050
240
1,100
1.2
1.3
1.3
EthyleneEthane__-Propylene_Propane.--
43.5
50.8
0. 1
1.6
01.0
31.4;
0. 2
0.8
75.0
21.9
0. 1
0.5
Butadiene..
0.2
0.1
_.O.1
00---001.--Conversion,
Selectivity, ercentm
‘Oxygen use , percent
1.3
0.8
49
88
:74‘
1.1
1.1
66
92
72
0.4
0.7
78
96
88
0-60
950
0.1
11.3
32.7
0. 1
0 9
-_
2
0.7
17
65
.18
120
1,000
.
180
1.050
240
1,100
120-180
1,050
240
1,100
1.8'
2.1
2.1
0.3
0.7
27.4
05.0
0. 2
0.9.
51.5
41.2
0. 2
0.2
67.8
25.2
0. 2
0.6
17.5
79.5
0. 1
0.3
31.2
64.8
0. 1
0.4
0.1
_____ __
0.3
0.2
0.1
2.0
1.2
75
91
85
1.0
1.2
21
85
23
1.5
1.2
35
89
38
3.9
v0.7
35
78
49
3.5
1.2
59
88
63
- 00 g. LiI'3Hs0 dehydrates' 03.43 g.-LlI.
Table 3,~which follows, gives further data on the concreased somewhat as total ?ow increased and oxygen
version of ethane to ethylenezutilizinglithium iodide and
utilization remained at 100 percent. Small amounts of
:lead iodide respectively in molten salt systems. In these
cyclohexene, benzene and toluene were noted in the prod
:experiment-s care was taken toob-tain optimum contact 70 not. These indicate that a limitedamount of a coupling
of the ethane and oxygen introduced together and furtherreaction was occurring. Coke make (data not shown)
.more the apparatus was designed to maintain maximum
was small.
agitation of the metallic oxide formed during the reacWhen isobutane was used rather than normal butane,
tion. Best results were obtained by using’ slightly less
entirely different results were obtained as will be seen by
than an equivalent amount of oxygen based on hydro- 75 reference to Table 4, The principal product was iso
.carbonso asto minimize loss .or‘iodine or iodine species
butene and there were no normal butenes or butadiene
8,080,435
10
successful, conversion at 1050“ F. ‘being 71 percent and
produced. At 1050" F., one second residence time, with an
air/iso-butane ratio of 5, conversion was 75 percent and
selectivity 92 percent.
The data contained in Table 5 which follows indicates
selectivity 87 percent with negligible coke formations.
This particular isobutane feed was technical grade (95
percent molar purity) and contained 4 percent propane.
The presence of small but signi?cant amounts of benzene
and toluene in the product shows that 1a coupling reaction
pling reaction and, consequently, benzene was obtained
in substantial yields in addition to the primary product,
propylene, propane being the feed material. With an
with propane or propane-isohutane mixtures occurs.
percent. Propylene selectivity was 71 percent and ben
that a residence time of about 5 seconds enhances cou
air/propane ratio of 4.4 at 1050° F., conversion was 83
Table 4 also shows the results obtained by similar treat
zene selectivity was 15 percent for a combined selectivity
ment of isopentane and of 2-met-hy1butene-1 for producing 10 of 86 percent. As Table 5 shows, propylene is an even
isoprene. At 1050" F. a 95 percent conversion of iso~
better starting material for benzene production. At 1050"
pentane was obtained, with isoprene and isoamylene se
F. conversion was 81 percent and selectivity 73 percent
lectivities of 58 percent and 13 percent, respectively.
for a benzene yield of 59 percent.
Conversion of 2-methylbutene-1 to isoprene was more
TABLE 4
Dehydrogenation in a Riser Reactor
Reactor type __________________ __
Riser
Salt ___________________________ __ Y—
LiI
Load, g.
x‘
_____ __
—\
-111
\-
4-)
Li: 0
Load, g-.-
#4
8. “
Hydrocarbon leed___
n-Butane
Feed rate, cc./m1n
Air rate, (KL/min _____ __
_
\
50 -——-——>
300 I
350
250 l
Reactor temperature, ° F _ _ _ _ __ <——-—-— ,
4-‘
Isobutane
125 l
Isonentane
(1)
50-—-———->
175 I
250
i 20
250
9 30
250
2 70
225
-———->
1, 000
1, 050
1,050
8. 3
0. 4
10.3
0.5
5. 8
0————-——>
Product percent In, basis feed:
Met ane _____________ __
___
'
2. 6
3. 0
1. 9
1. 9
7. 9
8.1
4. 5
5. 8
51. 1
Butylenes _________________ __
Isobntano
3. 6
n-Butane _________________ __
25. 1
Isoarr ylenes.
.4
_
3. 6
_
_
16. 2
Isopenmne
__
_
Isoprene _________ __
__
__
.
_
1. 6
0. 3
12. 2
28. 7
26. 3
5. 3
______ __
47. 4
55. 2
65. 3
1. 3
0 8
0. 3
Cyclohexene.
Benzene-.-
0.8
0. 9
0. 6
1. 1
6.4
0.3
Toluene
0. 4
0. 4
0. 4
0.6
0. 4
0. 8
0.3 ______________ -_
C .___
1.0
1.5
1.6
1.9
1.3
2.0
0.6
CO2 ____________ __
0.2
0.9
1.6
3.1
2.4
3.9
1.1
75
84
92
63
66
75
74
68
67
76
0.9
Conversion, percent In
Selectivity, percent 111.:
Butadiene _ _ _ _ _
_ _ _ __
Butylenes.
Isoprene. -
5
1. 3
4
2
3 78
_
_
_
85
0. 4
_
Isoamylenes-
73
64
71
85
87
Oxygen used, percent _________ __ <-——‘—100—————) <-———100-—-—-->
l 2-methylbutene-1.
= Calculated gas volume at STP.
0.2
95
71
87 ______________________ _.
______ __ _
__
1.5
______ __
_
______ _.
Z ___________ __
2.8
58
92
8
13
______ __
72
71
92
100
100
98
' 150.
TABLE 5
Dehydrogenatzon of Propane and Propylene
Reactor type .................... .-
Riser
Salt _____________________________ -_
Lil
Load, g_
‘i
111
ride _____ __
v?
L120
Load, g_____
Hydrocarbon feed- _
Feed rate, cc./m1n_-
r?
vi
Pro pan.
I 80
4 8o
4-‘
8.9
80
50
20
20
20
1, 200
050
1, 200
050
1, 250
200
1, 050
125
1. 050
100
1, 050
1%?)
1,a 050
1. 4
1. 7
1. 7
2.0
4. 0
1.6
1. 2
0.8
2. 2
3. 6
0. 3
6. 2
13.
6
1.8
3.
7
1. 4
0. 3
1. 6
3. 2
o. 3
1. 6
8.
4
0.3
42. 4
Air
Reactor
rate, temperature,
cc./m1n _________________
° F ________ ___
1, 250
000
1, 250
050
1, 250
050
0.8
0.5
0.3
1. 3
1. 0
0.3
Propylene.
38. 4
Propane-.-
49. 2
53. 7
58.4
45. 1
43. 8
55. 4
42. 7
31. 9
17. 2
Butadiene ___________________ __
0.5
1. 0
Cyt-ln'hovone
0. 7
2. 4
2. 8
CO __________________________ -_
1. 0
0.7
0.2
4. 9
0.1
Conversion, percent in ___________ -_
45
86
57
86
68
79
83
71
5
91
91
5
91
99
9
88
99
15
86
100
CO2.-.
Selectivity, percent 111.:
A‘
1.3
(Z)
<---——-Propan='-—->
1,050
350
8 100
1. O
25
L120
—\
4 80
1 100
Benzene _____________________ _.
LiI
—\
A‘
3 80
_
Products,
percent m., basis teed:
Methane ____________________ __
Melt-Pot
2. 5
8.0
0.7 ______ -_
52. 1
54. 6
53. 6
46. 7
44. 5
1. 9 ______ _.
25. 7
19. 0
19. 0
1. 0 ...... __
0.7
0.3
1. 0 ______ __
0. 3
0. 3
0.2
1. 2
0. 8
8. 6
11.3
12. 2
2. 7
3. 7
3. 5
74
70
81
68
81
66
12
82
100
14
82
100
15
81.
100
5. 9
11.9
1. 3 ______ -_
2. 6
4. 3
0. 5
0. 8
53
85
56
79
5
90
99
8
87
100
0.2
1 Methane and propane, 50-50 percent m. mixture, yields basis propane only.‘
6 He rate, ccJmm.
‘ Propane and air teed into riser.
top, air feed into riser.
29. 1
19. 4
58. 6
4. 8 ______ __
0.4
11.5
98
81
43 ______ __
30
73
I Propylene.
73
73
99
4.8
6.0
6. 2
3 Propane feed into bell
enemas
11
12
Table 6 shows the results obtained by treatment of
carbon-to-hydrogen ratio by means of reaction with io
various feeds with oxygen in a molten lithium iodide
lithium oxide mixture. The following results are of spe
dine in the presence of a molten metallic iodide compris
ing the steps of (1) admixing a hydrocarbon with a mol~
ten metallic iodide containing suspended metallic oxide
cial importance:
( 1) Dehydrocyclization of alkanes and alkenes re .5 and iodine at a temperature in excess of 200° C. where
sulted in the formation of aromatics and cycloole?ns.
in the ?rst hydrocarbon is dehydrogenated into the sec
(2) Aromatics are obtained by dehydrogenation of
ond hydrocarbon, hydrogen iodide is formed and ‘reacts
cycloalkane.
with metallic oxide to form metallic iodide, (2) separat
(3) Unsaturation of the side chain resulted in the for~
ing the metallic iodide from the hydrocarbon product,
mation of styrene from ethylbenzene.
'(3) reacting metallic iodide from step (2) with oxygen
(4) Acrylonitrile was the principal conversion product
to generate metallic oxide and iodine suspended in excess
.of propionitrile.
molten metallic iodide and (4) recycling the suspension
TABLE '6
Feed
n~Heptane
Temperature. ‘’ F _____ - .
Cyclohexane
Oyclohexane
E thylbenzene
Propionitrile
990.
980
1.050- .
1.010 __________ _ .
1.000.
Composition of melt.
LizO, percent w_____ 0
2.2.-
3.0__
3.0_.
2.3-.
2.3.
0.5..
0.5.
LizI, Percent w ____ __
Pressure. p.s.i.\z___-
1.000- _
Hexene-l
_ 2.1-...
0.5..-“
0.5.
100
99.5.-
99.5-..
99.5__
99.5.-
99.5.
N2. cc./minO2. cc./min
60
50.
60
"13
‘170
69
‘170
45
60
24
100,
20.
Feed rate. cc./hour ____ __
13.3. _
16.04- _
16.04-
16.04- _
16.04- _
9.2.
Oglfeed ratio. mol__.'____
1.5 ................ .. 1.05.“
'1-5"
0.45-.
0.41.
Composition of liquid
05.8: C6. 6.0; ben-
Benzene. 64;
Ethyl‘oenzenc .
Propionitrile. 65;
products.
Benzene, 90; cyclo-
0.5..
.
_ ‘1.0..
Benzene. 45; cyclo-
zene, l5; n-hep-
hexene . 1; hexenes
.cyclohexane. "
hexane. 52; meth-
23; styrene.
acrylonitrlle , 25;
grille. 28; toluene.
plus hexanes. 9-
36.
glcyclopentane.
77.
unidenti?ed. 10.
I claim as my invention:
1. In the process for the dehydogenation of a ?rst or
'
of metallic oxide and iodine in molten metallic iodide to
-~~step .(1) of the process.
ganic compound to at least a second organic compound 30
4. A process according to claim 1 wherein the metal
having a higher carbon-to-hydrogen ratio, wherein the
lic iodide is lead iodide.
?rst compound and a reactive iodine species are reacted
at a temperature in excess of 200° C. whereby the ‘sec
5. A process according to claim 1 wherein the metal
lic iodide is lithium iodide.
ond compound and hydrogen iodide are produced, the
.6. ,A process according to claim 1 wherein the metallic
improvement comprising conducting the reaction in a .35 iodide -is cadmium iodide.
molten salt environment, the .moltensalt comprising .at
7. ,A, process according to claim 1 wherein the ?rst
least one metallic iodide, and injecting oxygen "into the
compound is butane.
molten salt environment and thereby liberating iodine
8. ,A process according to claim 1 wherein the ?rst
from the metallic iodide to provide iodine for the afore
compound is heptane.
said reaction.
[9. ,A,,.pr,ocess according to claim 1 wherein the ?rst
2. A process for dehydrogenating a ?rst hydrocarbon
compound is a hydrocarbon in the gasoline boiling range.
into a second hydrocarbon having a higher carbon-to
,hydrogen ratio which comprises contacting a mixture
comprising the ?rst hydrocarbon with a reactantiodine
10. A process according to claim 1 wherein the ?rst
compound is _a saturated aliphatic hydrocarbon having
.from .1 _to 16 carbon atoms per molecule.
‘species in sufficient amount to furnish at least 0;0S mole 45
~11. A process according to claim 1 wherein the ?rst
of iodine per mole of ?rst hydrocarbon ‘at a temperature
compound is ethane.
of at least 200° C. to effect a carbon-to-hydrogen bond
.12. .A,.process according to claim 1 wherein the ?rst
cleavage in the ?rst hydrocarbon, contact of the reactant
compound is propane.
iodine species and the ?rst hydrocarbon being in a body
of molten salt comprising a molten metallic iodide, and 50
References Cited in the ?le of this patent
introducing oxygen into said molten salt environment and
UNITED STATES PATENTS
thereby liberating iodine from the’ metallic iodide to pro
vide iodine for the aforesaid contacting with the-?rstthy
2,868,771
Ray et a1 _____________ _.. Ian. 13, 1959
drocarbon.
‘42,868,772
Ray-ct al. ____________ __ Jan. 13, 1959
3. An improved process for dehydrogenating a ?rst hy 55 2,879,300
Cheney et a1 __________ __ Mar. 24, 1959
drocarbon ‘into a second hydrocarbon having a higher
2,890,253
Mullineaux-et a1.v ______ _.. June 9, 1959
Документ
Категория
Без категории
Просмотров
4
Размер файла
1 027 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа