US2001910A - Treatment of hydrocarbon oils - Google Patents

Description

May'zl, 1935. v. IPATIEFF 2,001,910

TREATMENT OF HYDROCARBON OILS I Filed oct. 28. 1932 Paten-ted May 21, 193s UNITED STATES Parent oFFica TREATMENT F HYDROCARBON GILS Application October 28, 1932, Serial No. 640,123

6 Claims. (Cl. 196-10) This invention relates to the treatment of hydrocarbon oils and refers more particularly'to the treatment of the low boiling naphthas and gasolines produced from crude petroleums by fractionation -under conditions involving substantially no cracking.

In a more specific sense the invention has reference to a process for treating said straight run gasolines to improve their quality with respect to gum and color-forming compounds preseht and in a specific sense in regard to improving their antiknock value and increasing their yield. The details of the process whereby these desirable reiining effects are -accomplished are given in the following specification.

In a general way the gasoline fractions present in crude petroleums and which may be removed therefrom by fractionation at moderate temperatures and pressures reflect the character of the crude petroleum, i. e., they may vary with the type of crude in the proportions of such hydrocarbon groups as parafns, olens, naphthenes, aromatics and the sulphur and nitrogen compounds which may be present. Although there are cases of considerable divergence from this rule, it has been repeatedly noted that the gasolines from parailinic crudes such as those from the Pennsylvania and some of the Mid-Continent fields are highly parafinic and highly knocking in character. 'Ihe gasolines from the Mid-Continent eldcrudes and some of the Gulf crudes have an intermediate character in respect to antiknock value, indicating possibly the presence of relatively higher percentages of cyclic compounds of the nature of naphthenes or of isoparaflins. Certa'h crude oils from the Pacic Coast producing reas and some Texas fields yield gasolines of comparatively high antiknock value, owing to the cyclic character of the crude oils. These observations as to the variable character of straight run gasolines are merely adduced in a general way to show that different gasolines or naphthas may require different degrees of treatnient according to the process of the invention to 45 be presently disclosed in order to render them up to the prevailing market standards for antiknock value.

The present invention comprises a process of treatment whereby the character of the hydro- 50 carbons present in straight run gasolines is altered in the direction of increased antiknock value.

The process furthermore effects a conservation oi' some of the waste products of cracking processes which are caused to combine chemically with certain hydrocarbon groups in straight run gasolines so that the overall yield of l product is increased by this synthetic step.

In one specic embodiment the invention comprises treatment of hydrocarbon mixtures of the character of straight run gasolines with olens in the presence of sludge sulphuric acid to produce hydrocarbons which add antiknock value 'to the gasoline and at the same time to produce other desirable treating eiects.

The term olefin as used within the concept of the present invention comprises any compound of carbon and hydrogen of open chain structure and containing one or more double bonds between carbon atoms. The following tabulation gives a few of the lower boiling members of the ethylene series which consists of homologs of the base substance ethylene containing one double bond:

Table No. 1

Beginning with compounds of four carbonV atoms, the table shows that a number of isomers are possiblecorresponding to different positions of the double bond and the presence of tertiary or quaternary carbon atoms, the number of possible isomers increasing as the number of carbon atoms increases. From these considerations it isv evident that for the ethylene series alone a large number of diierent olefins may be employed either singly or in admixture for condensation with paraiiin hydrocarbons according to the process of the invention.

The invention may further comprise the utilization of open chain unsaturated hydrocarbons of the acetylene or the diolefin series comprising such compounds as acetylene, butadiene,etc., and their homologs. While pure compounds of this character vand even ethylene itself do not react readily even with aromatics in the presence of sulphuric acid catalyst there is apparently some alkylation by these compounds when used in admixture with other oleflns as occurs in the caseV of gases from cracking plants.

The reactions involved in treatments accordi to the process of the invention are of considerable complexity owing to the large number of hydrocarbon types represented in the "gasolines caused to join with benzol to produce an alkylated may be considered. When gaseous prolylene is passed into a well-stirred mixture of benzol and concentrated sulphuric acid in proper proportions, the propylene is apparently sulfonated at first to prodce a monopropylsulfuric acid, and there -are indications that the benzol may be sulfonated to some extent. 'Ihe sulphuric acid derivatives then react to form a propylated benzol and regenerate to a large extent the sulphuric acid so that the net result of the reactions is expressed by the following equations which show the formation of monoand di-isopropyl benzol:

C H6 H H2804 C C H `C H 2) Prowlene Beienzoll Monos-isoproiyfbenzol 2C3He' -i- CH CH4'(CsH7)2 The relative proportions of the monoand diderivatives will depend upon such factors as the relative proportions of the two hydrocarbons employed, the rate of introduction of the propylene into the acidaromatic mixture, the strength of the acid and particularly the temperature which in the majority of cases of this Acharacter is best maintained at at least atmospheric temperature to minimize loss of olens by polymerization. In the above reactions propylene represents any of the homologs of ethylene, although ethylene itself is not specially reactive. Similarly benzol represents any of the aromatic series of hydrocarbons and may also typify the polynuclear aromatics such as naphthalene and anthracene. However, the proportion of these polynuclear aromatics is undoubtedly very small in straight run ggoolne fractions which commonly boil under The reactions given above in connection with oleflns and aromatics are obvious and readily understandable to those versed in organic chemistry. However, it isadvanced as a particular fea ture of the -present invention that unusual and unexpected results have been obtained when treating gasolines with olens and olen -mixtures in the presence of sulphuric acid when' the gasolines are ofa paraflinic character as produced from Pennsylvania crude oils and contain substantially no hydrocarbons of a distinctly aromatic character though possibly a considerable percentage of naphthenes. Owing to the diculties of exact analysis in the case of hydrocarbon oil mixtures only a limited amount of data is available on the subject of the proximate composition of gasolines, but considerable qualitative and some semi-quantitative experiments have indicated that the so-called paraflinic gasolines may consist not only of normal or straight chain parains but also to a large extent of so-called iso or branched chain parallns and cyclic compounds of asaturated orpartially saturated character such as the naphthenes and mixed alkyl derivatives thereof. The course of the reactions which lead to the improvements noted inA the case of straight run paranic gasolines when `treated by the process of the present invention may consist in rearrangements among the substituting groups either in the open chain or closed chain hydrocarbons, or it may comprise the direct addition of olens to central carbon atoms in the paramnic ing process and other chains. Such reactions cannot be closely followed owing to the difliculties in-'securing reliable analytical data.

'I'he following equations in addition'j-:tof those previously given suggest further reactions which may take .place when olens are contacted with straight run kgasolines in the presence of sulphuric acid under regulated conditions. In the case of a straight chain paraiin such as pentane, the following equation expresses a possible reaction:

CaHs *i* CsHlz CzHf'CsHn Propylene Pentaue Iso-propyl pentane Owing to 'the observed increase in antlknock value which occurs many times in the alkyla'tion of straight run gasolinesaccording to the process of the'invention it 'is probable that at least some of the methyl or other alkyl groups attach tofjtlre carbon chain in a central position so thatgisq: compounds are formed, since itknowii that hydrocarbons of higher antiknock value are tained when the carbon atoms are arranged more' compactly.

The equation given below suggests a- 'reaction which might be presumed to takeplace'betwee'n an olen and a naphthene or apartially' hydro,-v genated aromatic of a mixed or terpenelike character:

Propylene Dihydrobenzol Dihydro isopropyl beuzol The foregoing suggested. reactions, merely indicate possible trends and many other and more complicated reactions may occur owing to the possiblity of the shifting of labile hydrogen atoms and alkyl groups such as methyl, ethyl, propyl, etc. v l A feature of the present invention is that sludge acids resulting from the treatment of petroleum products, cracked distillates, gases. from a crackproducts containing ele-ns and aromatic hydrocarbons andthe like,;is 'employed as a catalyst and/or polymerizingagent in the process. When sulphuric acid isA used to catalyze reactions of the general character just described as occurring between oleflnsand other classes of hydrocarbons itsstrength must becarefully controlled and the temperature at whichfthe reactions are conducted must be held below a cer-g tain point if best results are .to be secured-in the production of yields of products of the-desired boiling range and quality. For example, inthe reactions between propylene and benzol-just-de, scribed best results'are obtained if the temperaf ture is maintained in the neighborhood of Qi C. When conditions are such that the reactions leading to the formation of alkyl derivatives of drocarbons predominate, it would appear that the initial stage of the reactions corresponds to theformation of sulphuric acid esters of o lelns and in compounds corresponding to sulfonicacids of benzol, which further react toform the-alkylated hydrocarbon and regenerate the .sulphuric acid. When sulphuric acid overa certain -limit strength is employed, .temperatures areallowed to rise, or there is a lack of intimate con? tact between the reacting constituents, therefis an increased tendency toward the formation of polymers of the olen's. This is particularlynd. ticeable .in employing oleflnic' hydrocarbons which occur in gases from cracking. processes since there are numerous types of olens .of highly unsaturated` character `present'. whose polymers are of a gummy ortarry character .and

hence undesirable in the alkylated product which is primarily intended for use as a blending material to improve the antiknock characteristics of motor fuel. Furthermore, unless conditions are kept within narrow limits, there is a tendency for the formation of highly alkylated hydrocarbons which may contain, for example, three or four substituting groups and which are of too high boiling character to be used in gasoline without unduly increasing its end boiling point.

It has been found that if sludge acids are employed in place of fresh acid that the conditions of operation in alkylating hydrocarbons to produce gasoline boiling range compounds admit of considerably greater latitude. There is less tendency toward the formation of gummy polymers or too highly alkylated compounds and owing to the more selective and moderate nature of the reactions there is a decreased tendency toward excessive temperature rise due to heat of reaction, and proper conditions of treatment are more easily maintained in practice.

The term sludge acid" as used in the present specification may refer to any of the partly spent acids used in conducting treatments upon any of the miscellaneous oils treated in connection with the refining of petroleum, and it also includes in its meaning sludges which may be produced in alkylating hydrocarbons with oleiins where fresh acid was employed, the last named class being in a sense recirculated acid. In other words the invention comprises the use of sludges resulting from the sulphuric acid treatment of such miscellaneous oils as gasolines, both cracked and'straight run, naphthas, kerosenes, lubricating oils, etc. Since the object in usingA sludge acid is to catalyze the desired reactions by acids diluted by soluble organic products rather than by water, it is also comprised within the scope of the invention to synthetically produce a sludge acid of desired characteristics by properly blending a sludge acid with fresh or unused sulphuric acid to produce a reagent of the desired activity. Obviously this procedure admits of the production of a large number 'of reagents of properties varying generally with the percentage and strength of free sulphuric acid present and while a number of alternatives are possible it is to be understood that they are not necessarily equivalent in their action.

lThe process of the invention is advantageously employed in connection with the utilization of the olelns in the gases produced as a by-product of oil cracking processes whose primary object is the production of gasoline. The amount of gas produced in such processes varies generally with the intensity pf cracking conditions and the olenic content of such v4gases is frequently very high, sometimes running i0 to 50% by volume in the case of gases produced in high temperature-low pressure vapor phase cracking proc-- esses. Such gases contain large amounts of ethylene, propylene, butylenes, and amylenes though usually propylene predominates, this particular olen frequently constituting as high as 30% of the total gas mixture.

According to the process of the invention individual olefins or mixtures of oleiins and other hydrocarbon gases vsuch as those present in gases from oil cracking processes are contacted with reactive hydrocarbons in the presence of sludge acid. While the process is not limited to the use ofI any `particular type of apparatus or plant arrangement it will assist in deiinng its character to describe an operation in connection with one arrangement of inter-connected elements which may be employed and for this purpose the attached drawing is provided which shows diagrammatically and without reference to any particular scale, an arrangement of apparatus which may be employed.v

Referring to the drawing, the essential features of the plant shown are seen to be a source of supply for olefin-containing gas, aromatic liquid and sludge acid, chambers in which the gas and liquids are reacted in the presence of the acid, settlers for separating the alkylated product from partly spent acids and neutralizing and washing tanks. The last named are not a special feature of theprocess as the lneutralizing and Washing of products from acid-treatments is well established in the art and, furthermore, the layout shown provides'.- no means for redistilling the puried'product though this may be done if and when necessary. Obviously the exact type of mixer for liquid hydrocarbon, acid and gas will be modified to obtain best results in any given case and the details of construction may be altered in accordance with special needs. However, `the operation to be described is sufiiciently illustrative.

In the drawing shown an Glenn-containing gas such as the mixture produced from an oil cracking process is introduced to thesystem through a line I containing control valve ,2, line l having a branch line 3 containing control valve 4. It is assumed for the purposes of the present discussion that the gas is under suicient pressure as it comes from a cracking plant so that pumping means are not necessary. An inlet gas pressure of about loll pounds may be desirable in processes of the present character as there is considerable diilerentialp encountered in the flow through the apparatus and the reactions are further assisted by pressure as will be later developed. In the present set-up, line 3 conducts the gas to a primary reactor 5 while line l serves to conduct it to a. secondary reactor V6'. The reactors'are provided with sprays -55 and 58 respectively and alsov superimposed perforated plates 56,- 51, 59 and Silas shown to break up the oil and acid into a fine spray or inist which is thus brought into intimate Contact with the gas, the reaction taking place with all constituents owing downwardly.

4In the arrangement shown the order of the reactors may be reversed, since the acid, gas and oil lines are manifolded but for purposes of the present description reactor 5 will be considered as the primary reactor in which the inlet gas rich in olefins is contacted with fresh hydrocarbon liquid in the presence of partly spent acid,`whi1e the residual gas from this primary operation is contacted with separate portions of hydrocarbon liquid in secondary reactor 6 in the presence of stronger acid. The concurrently principle of treatment, which is shown as a feature of the process in connection with the drawing, while a convenient and efficient mode of operation, is not an essential feature of the present invention, which may comprise operations of a oncetlirough orV batch character. The principle of concurrently treatment in connection with the present process may be applied in still other ways than that shown, since there are three separate substances participating in the general reactions, to wit, olefin-containing gases, hydrocarbon liquid and sulphuric acid. To enumerate some of the possible combinations it maybe stated that (1) gases and hydrocarbon liquids may be directed counter-current to acid, (2) acid and hydrocarbon liquids may be directed counter-current to gases and (3) acid and gases may be directed counter-current to hydrocarbon liquid. Any of these particular operations are comprised within the scope of the invention and may beutllized at particular times although for purposes of clarity 'the description of an \operation in which acid'is passed concurrently of hydrocarbon liquids and gases is generally adhered to. 'I he incoming gas isthus introduced to reactor 5 through line 3 while fresh hydrocarbon liquid mixed with sludge acid is introduced from line I4. All supply tanks and receivers are shown in duplicate arrangement to'assist in assuring continuous operation of the process. Thus hydrocarbon liquid may be taken by pump I3 from sup- 4ply tanks 1 or 8 either through line control valve I or line I I' containing control valve I2 and discharged through line I4 containing control valves I5 and I6 into reactor 5 as shown. Line I1 containing control valve I8 provides for the introduction of the hydrocarbon liquid into secondary reactor 6. Sludge acid from the reactions in the primary reactor 5 may be taken from either receiver 3l or 32 through line 33 containing control valve 34 or line 35 containing control valve 36 respectively'and pumped by pump'31 through line 38 containing control valve 39 to line 4I containing controlvalve 42 and' thence to line I4 and spray 55. The sludge acid catalyst may be continuously circulated to insure its maximum utilization and when its eifectiveness is reduced below an economical point by the gradual accumulation of solubleesters, etc.,-a

portion of it may be continuously or intermittently discharged through branch line 38' containing valve 39' and the necessary amount of make-up acid, either fresh or sludge, introduced from the primary sludge acid supply. If desired or if `advantages are gained thereby, partly spent acid from the reactions in the secondary reactor 6, obtained from tanks 43 and 44, may be recycled to the primary reactor 5, valve 54 being entirely or partially closed and valve 52 being open at such times. In ordinary operations the sludge product from the secondary reactor will be circulatedby way of line 53 containing control valve 54, line 26 and line I1 until its emciency drops below an economical point- To reduce polymerization and undesirable side reactions the products from the reactor are-discharged in toto through a cooling coil prior to their separationinto a sludge acid layer, alkylated liquid and unreacted gases. Thus a header 6I contains valves 62, 62', 63 and 63' and permits the utilization of cooling coils 64, 65 and 66 as may be found most expedient. Similarly a header 61 may receive cooled products from any one t. o1' the three coolers and direct the cooled products to either one of settling tanks 10 and 13 by the proper manipulation of valves 66 and 69.

gas, hydrocarbon vliquid andsludge 'acid from the primary reactor separate, the gas being -released through line 16 containing control valve 11 to line I leading t0 secondary'reactor 6. 'I'he liquid product shown as layer 1I may as desired be recirculated to the primary reactor, further. treated in the secondary reactor or withdrawn from the process for neutralizing and washingas a nal product. In the first case a pump 90 may withdraw the liquid layer through line containing a control valve and return the partially alkvlated liquid to the primary reactor by way of line 9| and valve 9 containing 92, line 9|' and valve 92land line I4. When the partially alkylated liquid products from the reactor are to be treated in the secondary reactor, valve 92' is closedand the liquid proceeds to the secondary reactor by way of lines 26 and I1. zIn the event that further alkylation is .not desired the liquid product may be diverted into line 93 containing control valve 94 and thus through line 95 containing control valve 96 (whlchserves a similar plu'pose for the corresponding material in settling tank 13) into neutralizing` tank 91 to be laterdescribed. Partly spent acid from settling tank 16 shown as layer 12 may be drawn to intermediateaccumulators 3| and 32 through line l0 containing control valve 87| or line 82 containing control valve 83 respectively as may be expedient. When the sludge from this stage -is to be further used, pump 31 is used for recirculating the first stage sludge acid into reactor 5, the stream being, diverted through line 4I containingl control valve 42, valve 40 being closed. l

In secondary reactor 6 according to the'. flow at present being described fresh. or partly alkylated hydrocarbon liquid is contactedwith'the olefin-containing gas from the rst reactor in the presence of sludge acid of relatively/.greater activity. The main advantage gained by this operation is that more acid may be used and a higher rate of .alkylation effected without inicreased tendency' toward polymerization among the oleflns, since these no longer comprise the more readily reactive members which were lost in the primary reactor. Thus sludge acid from a source outside the processmay be taken from supply tanks I9 or 20 through line 2| containing control valve 22 or line. 23 containing control valve 24 respectively and pumped by pump 25 through line 26 containing control valves 21 and 28 into secondary reactor 6. The products of this second stage in respect to the gas'or the primary stage in respect to the acid may then be discharged through a cooler selected from those already described and passed to a settling tank, in the present instance settling tank-13 which shows again alkylated hydrocarbon liquid" as layer 14'and sludge acid as layer 15., The gas from this stage, being now` substantially free from reactive olefns, is vented through line 16 containing control valve 19 and may be put to any use for which it is suited;

The sludge acid from the second'stagev is drawn from settling tank 13 to tanks 43 and 44 through lines 84 containing control valve 85 or line 66 -containing control valve 81 and may be further used in either of the reactors as its strength may indicate, though in the preferred mode of operation itwill be used inthe primary reactor 6 for reasons which have been already given.' Thus pump 49 may withdraw this acid from tank 4,3 through line containing control valve 46 or from tank 44 vthrough line 41 .containing control valve 48 vand discharge it through line 56 containing control .valves 5I and v52. When this sludge acid is to be used in primary reactor 5, valves 5I and 52 will be open'and the acid-will pass directly to line I4. If used for any reasons in secondary reactor `6 it may be diverted through branch line 53,containing` control valve. 54 and- .ultimately reach the reaction zone through line 'lli ply consisting of sludge having a relatively high sulphuric acid concentration.

The alkylated hydrocarbons from settling tank 'I3 may be passed to the neutralizing tank through line 95 containing control valve 96 either alone or in admixture with analogous products from settling tank 10 as previously described. Caustic soda of any desired strength may be taken from tanks 98 and 99 through line |00 containing control valve or line |02 containing control valve |03 and pumped by a suitable pump |04 through line |05 containing control valve |06 from which it is allowed to pass downwardly counterflow to the ascending alkylated products. The neutralizing tank is preferably so designed that the rates of oil and alkali can be adjusted and a substantially neutral or slightly alkaline liquid may be recovered from the top of the tank, this liquid passing through line containing control valve 2 into a water Washing tank H3. To provide for the removal of any accumulation of gases a vent line |26 containing control valver |21 is provided in the top of the neutralizer. Line |01 containing control valve |08 permits the removal of spent neutralizing liquor. Line |09 containing control valve H0 is provided to permit the recirculation of a portion or all of the caustic solution as long as it retains sufncient neutralizing power.

In the water washing tank the same counterflow methods may be employed, water being introduced through a line H4 containing control valve ||5 in the form of a spray and the washed product drawn from the top of the tank through a line ||8 containing control valve I9 and passing either to final receiver |20 through line |20- containing control4 valve |2| or to receive |25 through line |22 containing control valve |23.

A commercial application of the process of .the invention is well exemplified in the treatment of a straight run gasoline with the gases from a cracking process. In such operations several modes of procedure will present themselves to those conversant with commercial practices. In the simplest case a selected sludge containing approximately .75% sulphuric acid equivalent may be stirred into a stationary body of gasoline in a batch agitator and a stream of olencontaining gases bubbled through the suspension through a spray or other distributing means. It is usually preferable to have cooling coils` immersed in the reaction mixture so that excessive temperature rise is avoided.

The example involves the treatment of a Pennsylvania straight run gasoline with. the gases produced in cracking a fuel oil distillate from the same crude. The gasoline before treatment may have the following properties:

Gravity A. P. I 65.0 Initial boiling point 'F 100 overv at 152 over at 180 I over at 1 200 40% over at 217 50% over at 234 60% over at 250A 70% over at 26,5 80% over at 288 90% over at' 322 End point (97.5%) 380 When a blend of 90 parts of a test gasoline showing 67.5 octane number and 10 parts of this gasoline is tested, an antilmock value of 52 octane number is obtained.

This gasoline may be treated with an oleilnic gas mixture containing approximately propylene by volume, this gas being produced in conjunction with cracking the fuel oil -distillate to produce gasoline. In the run 5.5 gals. of the straight run gasoline, 4.0 gals. of sludge acid-and 1860 cu. ft. of the gas per hour may be injected into a mixing box at the top of a tower through which the injected 'materials pass downwardly. As a result a volume of 235% of alkylated hydrocarbons may be produced based on the volume of the original gasoline. The properties of the alkylated product may be as follows:

When this product is again used in 10%' blend with the reference fuel of 67.5 octane number,

`the blend may test 83 octane number which indicates the remarkable improvement effected by the treatment since the average boiling point of the product is considerably higher than the original gasoline and yet the antiknock value is much higher as shown by comparing the o'ctane numbers.

The blending uid thus produced may be distilled after a caustic wash with no change in color or odor or the development of sulphur compounds due to decomposition of soluble acid esters.

The foregoing specification has described and disclosed the general and broad character of the invention and the example is'suillciently indicative of its value from a commercial standpoint. However, the invention is not limited in scope to the exact details of the descriptive material or the experimental data given.

I claim as my invention:

l. A process for the treatment of straight run distillate containing gasoline hydrocarbons to produce high anti-knock motor fuels therefrom and to increase the volume thereof suitable for high anti-knock motor fuels, which comprises simultaneously subjecting said straight run distillate and gases resulting from a cracking process to the action of preformed sludge acid clerived from the treatment of hydrocarbons with sulphuric acid, reacting components of the distillate with olefins contained in the gases to form alkylated derivatives, and recovering the resulting liquid product.

2. A process for the treatment of straight run distillate containing gasoline hydrocarbons to -produce high anti-knock motorfuels therefrom and to increase the volume thereof suitable for high anti-knock motor fuels, which comprises simultaneously subjecting said straight run dis- Y produce high anti-knock motor fuels therefrom and to* increase the volume thereof suitable for the distillate with olefins contained in the gases to form alkylated derivatives, and recovering the resulting liquid product.

4. A process for the treatment of straight run distillate containing gasoline hydrocarbons to produce' high anti-knock motor fuels therefrom and to increase the volume thereof suitable for high anti-knock motor fuels, which comprises simultaneously subjecting said straight run distillate and gases resulting from a cracking process to the action of preformed sludge acid derived from the treatment of cracked' gases with.

sulphuric acid, reacting components of the distillate with oleiins contained in the gases to form alkylated derivatives, and recovering the resulting liquid product.

5. A process for increasing the anti-knock value of light distillates containing a substantial quantity of hydrocarbons within the gasoline vboiling range, which comprises forming alkylated compounds in the ristillate by reacting components of the latter with oleiins in the presence of preformed sludge acid derived from the treatment of hydrocarbons with sulphuric acid. 10

6. A process for increasing the anti-knockl value of 'light distillates containing a substantial quantity of hydrocarbons within the gasoline boiling range, which comprises treating the distillate with oleflnic gas in the presence of preformed sludge acid derived from the treatment of hydrocarbons with sulphuric acid, reacting components of the distillate with oleilns contained in the gas to form alkylated derivatives,

and recovering the'distillate containing the de- `2o rivatives thus formed.

VLADIMIR IPATIEFF.

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