DE1593139A1 - Process for the separation of hydrocarbons - Google Patents

Description

Process for the separation of hydrocarbons

The invention relates to a method for separating hydrocarbons st off geraischen with a narrow boiling point range, in particular for separating a mixture from close together boiling, differing in the carbon / waeeeratoff ratio Hydrocarbons by bringing together one such a mixture with a specific aliphatic dinitrile that as a selective solvent for the more unsaturated one Hydrocarbon worked

Bs are 2UR implementation of procedures of this kind, two basic paths "On one hand, can the steam by the relatively high boiling selective solvent in a spray, packed columns or bubble-cap column wash _t wherein

009819/1827

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-a-

a flow of the selective solvent is conducted in countercurrent to the steam ο On the other hand, one can use the extractive distillation, in which the solvent is allowed to flow downwards in a distillation column during the progress of the distillation and during the rise of the vapors from the bubble o In this way takes place in a first zone, a washing of the Dull by the solvent * wherein the more soluble component is selectively dissolved _p and the resulting laden solvent is ^ a higher 5? euperatur first and in a second zone through the vapor rising reboiler of the out-of- Zone has ₉ partially stripped off = If desired, the contact zones can be operated essentially isothermally, The dissolved components are then usually obtained by distillation from the loaded solventί and the lean solvent produced is recycled = Using the above methods is it often possible? Separate constituents of a group of compounds with a narrow boiling range? whose separation is difficult with ordinary distillation methods? if not impossible _s

The practical usefulness of any such procedure depends on one view! on factors such as the relative volatilities of the dissolved substances, the concentrations of the dissolved substances, the resistance of the solvent and the ease with which the dissolved substance and solvent can be separated ₃ These factors vary with the working temperature

~ ² ~ _BA D

0098 19/182 7

NDCC 22

-y-

and the work pressure .. These complex relationships make it impossible to find a simple criterion for the evaluation of the Process efficiency and, in particular, the role that the solvent plays in determining the final efficiency If you play to win, you have to enpiriech as much as possible proceed?

The present invention provides an improved vapor flow phase method for separating or purifying closely boiling hydrocarbons with different carbon / hydrogen ratios from mixtures thereof and thus for separating aromatic hydrocarbons from non-aromatic hydrocarbons or from unsaturated, non-atonate hydrocarbons from their Irish nit less ungeaättigten _s nichtaroraatischen Kohlenwasaerstoffen only available *

It was found; that with 2'-Mthyl {ilutarsfiuredinitril as an extractive solvent - 'a highly effective separation is obtained in the processes described above win ,, which is obtained by dimerization of acrylonitrile. To carry out the catalytic hydrogenation, a palladium-on-carbon catalyst can be introduced into a stirred reactor together with the 2-methyleneglutaric acid dinitrile, about 0.1 to 55% of the catalyst, based on the 2-methyleneglutaric acid dinitrile, being used. Then it will be

0098Ί1 / Ί827 bath

NDGG 22 Hf 7

Hydrogen added? while the reaction mixtures at a pressure of about 2-136 atm *, preferably about 14-68 atm ** and preferably at a temperature of about 20-00 ° C _9, about 40 to 70 ° C, rührt.-. The reaction is continued _s until the required amount of hydrogen has been absorbed. Ο The 2-methylglutaric acid dinitrile produced is filtered to remove the catalyst pest particles.

^ The present invention is particularly suitable for the separation of aromatic hydrocarbons from fractions of relatively narrow boiling range _f which contain both aromatic and non-aromatic hydrocarbons. Components of a solution whose normal boiling points differ by less than about 30 ° C "are generally simple DeatiXliertechniken difficult to separate geraäss The method of the invention, however, allows ee _r ζ- B-, benzene from its Geraischen with cyclohexanes Cycloh9xen _f η-heptane, 2 , 2,4-trimethylpentane, 2,4 _f 4-trimethylpentene and others: ' _t . Toluene from its mixtures with 2 _S 2 ^ -trimethylpentane.,

ψ Sf ^^^ Triaethylpen-beris · ii-0G'ban _r Octene-1 _f Octene-2 »Ethylcyclohsxanj 2,6-Octaöien, ■ · Vinylcyclohexen," 1, 3,7-Octatrieni 1,3 _f 6-Ostati ^ ien etc. Q-- and, a- or p-Xylcl of aelnen Geraisehen with cyclooctane;. separate 1, 5 = _P -Cycloootadien Cyclcooten etc _o,

Iu gradients verschiedenar Kaffinatj-onsarbeiten fall mixtures of a number of the aromatic and non-aromatic hydrocarbon of the above-mentioned * Such mixtures include Roherd cl ₇ Erdölcrackungsprodukte, Erdölreformate, uew by hydrogenative cracking or coking of coal-derived oil. It

■ - I * BAD ORIGINAL

0098 19/1827

NDCC 22 ■ ~ 5 ~ ■

iirt of high interest and technical value to be able to easily and efficiently recover the aromatic components of the mixtures. ₉ "The-present 'invention provides a simple, effective and continuous process for the disposal, to by treatment of such mixtures of them in pure form essentially obtain all aromatic components *

Other aromatic hydrocarbons ₉ which can be separated according to the invention ₉ include alkyl-substituted benzenes, 3o B ₀ toluene, xyIoI ₉ trimethylbenzene, tetramethyl taetiRols, ethylbenzene, n-propy! Benzene, cumene and ethyl toluene, ■ ary! Substituted bensoles, eg ₀ diphenyl _p aromatic hydrocarbons with condensed rings? Zo Bo naphthalene and alkylnaphthalene, such as methylnaphthalene, dimethylnaphthalene, ethyl naphthalene and other haphthalene derivatives, such as phenylnaphthalene ₉

To. Non-automatic hydrocarbons from which the aromatic hydrocarbons can be separated according to the invention include saturated, aliphatic hydrocarbons, e.g. B _a Hexane, Heptane, Octane, Nonane, Dodeeanp Tetradecane ₉ Ieo- -pentane ». '2-Xthylhexane "2 _P 2 _E , 3 ^ra triraethylbutane _p 2,4-dimethyl pent an., 2,5-dimethylpentane _p 2 ^^ - trimethylpentane etc _ü9 unsaturated, aliphatic hydrocarbons, including monoolefins, Zc Bo hexen 1, hexene-2, 2-kthylbutene-1 ₉ 2 ~ methylpentene ^ T, 2 ~ methylpentene-2, 4-methylpentene-1 "octene-1 ₉ 2,4,4 ~ trimethylpentene-2>diolefins", ζV Β " 1,5-hexadiene and 2,6-octadiene, and triolefinens Zo B, 1 _s 3 ₉ 7-0ctatriene

009811 / Ί827

NDCC 22 '■

and 1.3 _r 6 ~ © n 0etatri, saturated cycloaliphatic Kohlenvmöoerstoffe, a "B ₀ Cyolohexan, Hethylcyclöpentan and cyclooctanes unsaturated" cycloaliphatic hydrocarbons, egg nschlieaslich Cyclomorioolefinen »z, B ₀ cyclohexene and cyclooct-to _p and Cyclodiolefinen, z ' Bo cyclohexadiene and cyclooctadiene.,

It is, as mentioned above, also possible to use the method according to the invention to other separation processes as the separation of aromatic from non-aromatic hydrocarbons, Thus, the process is Z ₅ B ₀ use it to disconnect non-aromatic hydrocarbon compounds different degree of saturation, each of said Hydrocarbons contains at least 6, and preferably about 6 to 15 carbon atoms; Such separations include Zo Bo's separation from Kaxen! and hexene-2 from hexane _p from cyclohexene, from cyclohexane or hexane "from heptenes from heptanes." from octatrienes from octartienes "octenes or octane _? v © n vinylcyclohexene of Dinsthyleyclohexan or iitliylcyclohexanj, won cyclooctadienes of CyclooctadieHf cyclooctane octane ν of Dodecsnen dodecane "of pentadecen- of pentadecane and the like ^ _s The above non-aromatic hydrocarbons, thus uafassen alipha tables and cycloaüphati- 'see hydrocarbons? including aliphatic hydrocarbons such as alkanes _t monoolefins _p diolefins etc.

The solvent of the invention can also be used for this purpose are »mixtures of low, non-aromatic

w6 - ORIGINAL

00 9 * 8 * 19/18 27-

HDCC 22. "■■■■.." T *

To separate hydrocarbons of different degrees of saturation. "Such work includes a" Β "the separation of butadiene from butenes and butanes" from butenes from butane "from pentadienes and isoprenes from pentenes and pentanes" from cyclopentadiene from cyclopentene _v pentenes and cyclopentane U8Wο For. These separations are already processes using solvents such as furfural , dioxane, diohloroethyl ether, aniline, glycol monoacetate "(ilycol diacetate? Glycol monomethyl ether, 95% ethyl alcohol ₉ different water-soluble polyhydroxy compounds such as ethylene and propylene & Lykolf and mixtures thereof have been described, however." that the above solvents are limited to separations of hydrocarbons containing not more than 5 carbon atoms. The 2-methylglutaric dinitrile solvent according to the invention has been found to be particularly suitable for the separation of hydrocarbons having 6 or more carbon atoms.

The best working temperature in each case changes with the the work sustained pressure and involves a compromise. * In general, the selectivity of the 2-methylglutaric acid dinitrile increase with temperature, while at the same time as the temperature rises, the absolute solubility falls, so that each other independently of what level the selectivity could reach in the The boiling point of the 2-methylglutaric acid dinitrile at the present pressure did not dissolve any hydrocarbon essentially

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00 9819/1827 ^{8ftD 0BlG4NAU}

NDGC 22

In most cases, nan works preferably at a temperature _p which is significantly below the boiling point of 2-methylglutarsyl dinitrilop but slightly above the condensation temperature of the most easily condensable component of the vapor at the present pressure.Practical tests have shown that when using 2- Methylglutaric acid dinitrile at essentially atmospheric pressure for the separation of benzene from non-aromatic Cg hydrocarbons, temperatures in the range of about 65 to 90 ° G are very suitable. Similar temperatures can be used for the separation of mixtures of non-aromatic hydrocarbons «

The pressure can be kept at essentially atmospheric pressure, but the extraction can also be carried out under positive or negative pressure, if care is taken to set the temperature so that the mixture to be extracted does not condense and 2-methylglutaric acid dinitrile does not evaporate excessively. Under pressure may be desirable _for a polymerization or destructive action to avoid delicate fabrics =. The amount of 2-MethylglutarsUuredinitrils mindeotens to satisfy _r around the main portion of the to be extracted component to löoen-. In various cases, a considerable excess over this amount can also be used, in particular? if the last traces of the more soluble constituent are to be washed out of the steam - The most economical amount in each case can vary depending on the temperatures and pressures used as well as the particular mixture to be extracted.

"Q ^ ßAD ORIGINAL

0 098Ί9 / Ί8 27

NDCC 22

-i-

A regeneration of the 2 ~ methylglutax ^j 8äuredinitril8 can be done according to all the conventional methods, e.g. by heating and / or pressure reduction, and the solvent regenerated in this way can be returned to the contact zone for use in a further working cycle.

The "effectiveness of 2-methylglutaric dinitrile as a solvent for the separation of various aromatic hydrocarbons ¹ , from various non-aromatic hydrocarbons by extractive distillation has been determined with the aid of Darapfphaaenchromatographie ₀ gas chromatography before columns are known to represent essentially multi-bottomed columns for extractive distillation where Y / irkungsweise the immovable Plüssigphase that of a solvent for the extractive distillation comparable ■ iatV the residence or retention times of different _s are connected to the immovable liquids miscible compounds when passing through the column, the solvent containing the Flüchtigkeitenρ which these compounds with "an extractive distillation yield would, inversely proportional _a If any two compounds differ in their residence times »they are accordingly separable by extractive distillation« where the Connection with the smallest dwell time is first passed over by η

OO 9819/18 27

NBOG 22

B e i 3 ρ I e 1

Ala column are 2 "4 α (8 puss) 6", 4-mm-Kupierrohr 0/4 inch) used ρ the with 19 g sine? Packing of 75 C-ew "# inert carrier (60/80 Mae ehe η, silaniertea Chroniosorb / w) and "25 Gavy # 2-, lIethylglutaröuredinit-il is filled. The column filled in this way is inserted into an apparatus for vapor phase chromatography of the type "Aerograph 700". By means of a helium stream, gaseous samples of various aromatic and non-aromatic hydrocarbons are passed through the filled column at different flow rates and temperature. Results:

Tabel

Carbon dioxide üiec
gur.lt : t _? Column
tempera «.
ture _P ⁰ C G-asatrö-
raungaga-
s chw -. _t
approx / min ^ BATH Stay-
time _r
Min ·, -;, _ - ■ benzene ÜC ,1 50 55 21 _? 7th Gyolohexane BC _S 7 50 55 - .5-, V- '' Cyclohexone 83 s.-2 50 55 5.7 benzene 80 »R 72 100 η-heptane . 9ß y4 72 too ^: Q _? B ■ Mothyicyolohexane 100 r9 72 100 ■ 1.5; . · - ■ 2,2,4-Tr: Lme -thyl-
psjitan 99 72 100 0.8 2 »4-, 4-door: lme-methyl-
penten - ■ 101 72 too ) 3 j - toluene 110 _P 6 ■ - "72 100 ; 12 ₉ 6 2 9 2,, 4-Tr L-methyl-
pentane 9Ϋ »3 · 72 too 0.8 2 _f 4 _P 4 ~ Tr: Lraethyl ~
penten 101 72 too 1.5 Methylcyclohexane 100 ν 9 72 TOO 1 * 5 00 93 - 10 ~
1Ö / 1 8 27 ORIGINAL

Nl) GC 22

n-octane
Qcten-1
Ethyl eye 1 σ hexane

2,6 octadiene
VinyIcyc1ohe xe η-4

1.31 6

m * xyloi

p-xylene

o-xylene

Gyclaoctane

.1, 5-cyclooctadiene Cyclooctene

C T a. "be lie Λ (Fo'rtaetzuttif)

Carbon dioxide boiling

sparked;

125.7

121 r 2

131.8

125.2

122

129 * 3

124

130

91

144.4-151.1 i50 _f 9 144

Column
tempera
tur ν C GaaatrÖ-
raungage-
coVMin. Stay
time _r 72 100 • 1.7 72 100 2.6 72 100 3.2 72 100 3.9 72 100 4.6 72 100 .7p7 . 72 100 9 _f 4 72 100 11.2 72 100 24 ₁ 2 72 100 24.4 72 100 32.3> 72 100 7v6 72 100 23.0 72 100 9 _t 0

B ei 3 ρ i el 2

Ta a three-way bottom flask fitted with a cooler and a counter clock _; A series of ternary CreE mixtures of 2-methylethylenedinitrile benzene and cyclohexane are brought into equilibrium. Small samples of the pliable and dairy phases are taken with the aid of insectic syringes and oils are analyzed by vapor-phase chromatography. The results are shown in to table B

11 -

00 9819/1827

, IiDGG 22

: k.UIÄg ρ

2 = Kfe- ~ Ben-

sol iaexap. S ig shaped

0 55 ₀ ? U0 - "77» S "55 * 1 443 1 ₉ O1

1.S ₉ I 5SpO 26p9 76 _e 5 - '51- »5 39» 8 - 1 _f 2 $

26.0. 31.5 23.5 77.0 '51.2 42.2 "1 ₉ 35

41 pO 40 »2 18 ₈ 7 - ■. 27 »6 5% S _ 1» 90

88 * 0 7 _P 8 4 ₉ O '' 83? S 23p® Si ₉ O 2.10

free®? Base

At & pi

On every 30o sowing of a 60-bpden deetillierk.olonfte "! © in © emieefe from 30"? & Öjclohejsan unü 70? E BensoX with a temperature of .80 ° G and a speed of. 10 ml / min listed * Aa 3 " bottom from the top, the column outside is supplied with liquid β-2-methylgltitaric acid at a temperature of and at a rate of 14 rai / ml

The overhead product ^: is taken from the top of the column at a reflux ratio of 5 s 1 and a temperature of 80 ° C with a; Rate of 180 ml / hr _e abgenommenο The Boäenprodukt is at a rate of 21 ml / Win, on the 5 ° Bode. a 10-tray column at a temperature of 85 ° C

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0 0 9 819/1827 bad original

. BI) CC 22

- introduced α The evaporator temperature of this column ^is: to 275 ° 0 held ο The overhead product is "at a Rüekflussverhältnis of 1 $ 1 nit at a rate of 7 ml / Minο removed ₉ while the bottom product in a circuit with 14 ml / min. "leads back to the third tray of the first column".

The overhead product from the first column contains 99 # 1 f cyclohexane and benzene * "and that of the column 1 aweiten $ GyelohexaE and 99 ^a k benzenes.

Example ^

Using the same device as in Example 1 the effectiveness of 2-Methylglutaraäuredinitrils as Solvent for extractive distillation "at the Irish ration and purification of non-aromatic hydrocarbons with different degrees of unsaturation beatimnta results:

'S abe 1 1 e G

Hydrocarbon boiling column gas flow, dwell point ρ 0 temp «, C geachwo» time _p min

^ ytei

_$ 1 -6.47 25 60 0 &

trans-butene-2 0.5 (744 25 60. ¹ »2

üia- <butene "2 3 _B 73 ^mO ^ 25 60 1.3

1 _s 3 ~ butadiene ~ 4 ₉ 5 25 '60 2.1

η-hexane 69 ₉ 0 25 -! 55 _2 * 1

Hexene-1 64.1 25 ] 55 A ₉ Z

Hexene-2 68.0 25 55 4.5

Cyclohexene 83 25 55 8.5

CycXohexane 81.4 50 55 3 _f l

Oyclo ^ xen B ₃ ^ " φ _f ^ 55 5.7

T593139

NDOC 22

(! al) el le C Column ) Yerweilr
«Eit, (Continuation) 25th 5.5 Hydrocarbon Boiling
sparkles, 25th Gaaatrö-
inequitable
eohwindo,
omr / Kin * TO ₉ 5 n-heptane 98.5 25th 55 8.2 Hepten-2. 98.2 25th 55. 15.8 n-ootan 125.7 72 55 1.7 Otites-.1 121.2 72 55 2.6 n-octane 125.7 72 100 3.9 Ooten-1 121.2 72 100 4.6 Octene-2 125.2 72 100 9.4 2,6-ootadiene 122.0 72 Ϊ00 11.2 1,3,7-octatriene.-. 124.0 72 100 3.2 1,3,6-ootatria 130.0 72 100 3.4 Ethylcyclohexane 131.0 72 100 7.7 oia-1,2-dimethyl-
cyolohexane 129.0 72 100 7.6 Vinyloyolohexen 129.3 72 100 9pO Cyoloootan 151.1 72 100 12.8 Cyolooots 144.0 72 100 23.0 1,3-cyclooctadiene 141.0 100 1s5-cyclooctadiene 150.9 too Be ie ρ i β 1 5

On the 30 ° bottom of a 60-plate distillation column is a geraißoh of 4J 1 » n-octane and 60 5» 0cte; n-1 with a temperature of i 28 ° iJ and a rate of 4 ml / ilin, on ige- f leads. At the 3 »bottom of the top of the column, liquid 2-methylglutaric acid dinitrile with a temperature above the temperature is found. of 125 ° C and one

Oesohwindigkelt from _: 20 AD

introduced

- 14 -00 98 19/1827

BAD ORIG'NAU

$ β. 1 ~ m & one ?. temperature of 124 ° C

io abgenocuaenö Dae Boden- vmi 2S ₉ 4 ml / Mia ο. ' up, ©! be a bucket

1st salary®a. _} Maa aisiat Sas llteerfe © pfproäulst "at

with ®ii

cÄttM.-4öJP. © f ^ töR Euleaae contains S6 Sq ₁ 0 © tan

4 yes _v §o% © a "isiii da® | eaAgö'der s *« © it © E Kölona © 9?? J

man
ii -l © "i (gHtt. maö ^ i ^ ksam © ine diversity- ftah« together aie- .. ■

_t precautionary * »indeet © na.6 Kohlsn» Söhl «nwaaeeystofie _f tReaaen know,. . ^: Clio ia ^ rseliioeaitsm Örude unsaturated are "show" stcii i roiaatiBche KohlenwaBoeratofie wtrkaam of Kohlenwasaeratoffen The values can be separated and DEAE hit the same success ^r jer * nnungen ettiechen versohieeenen acyoli-

and cyclic hydrocarbons are relatively closely related Biedeputilcteii can be carried out, if those in the Dehundluniüageaischen viMrlieg «nd # n Kohlenwneaeratoff · verechieden *

aufiteiaea,

'■ - 15 - ■ "'" ■■ -

009819/1827 _BAD

Claims (2)

NDCG 22. 2nd February 1966 jiuu .- 'e. J ⁶ - ¹ L., Fr ^an . ^a P ^r , ^ 9, ft., ft ο method aur separation of a Gemiacha closely boiling hydrocarbons _f in Kohlenntoff / Waeserstoff ratio differ _9, characterized in _t that a gasfönaiges OeniBch the hydrocarbons with liquid Z-methylglutaronitrile the extractive distillation is subjected and the hydrocarbons relatively high in this way, with a Selectively dissolves the carbon / hydrogen ratio and, on the one hand, extracts the hydrocarbons in the vapor phase with a relatively low carbon / hydrogen ratio and, on the other hand, the hydrocarbon fraction with a relatively high carbon / hydrogen ratio, 2- A method according to Anapruch _f 1 characterized in that j of the hydrocarbons with a relatively high Kohlenetof. '/ ~ Wuafcier8toff Verhältnäs i'lusslgphase ground in the resulting · strips the 2-methylglutaronitrile. 3 = method according to claim 1 and bzsvio or 2 _P characterized _f that nan a (Jemiach close to each other boiling hydrocarbons are used ^ which contains aromatic and nonaromatic carbon compounds _f where the non-aromatic hydrocarbons.relatively lower carbon / v / ae = hydrogen Show more than the aromatic hydrocarbons BATH ORIGINAL ■■■ '- ^; ■ -. · ■ = ■ - 16 ■ 0098 19/1827 HDCC 22 4 »The method of claim 1 or 2 and _o BAW" _Β characterized in that close to each other hydrocarbons boiling a mixture of non-aromatic hydrocarbons nit different carbon ütoff Au treated mixture / one etat Vässerstoff-Verhältriissen. 5ο method according to one or more of claims 1 to 4? characterized in that _p nan nichtaroinatiache hydrocarbons Rait 6 to 15 carbon atoms began 6 "Use of 2-MethyXglutar ⁱ acid dinitrile as a selective hydrocarbon extraction solvent in the process according to claims ϊ to 5» · 00 9819/1827