US3560341A

US3560341A - Process for the removal of straight chain hydrocarbons from petroleum fractions

Info

Publication number: US3560341A
Application number: US755019A
Authority: US
Inventors: Alfred Champagnat; Jean Antoine Filosa
Original assignee: BP PLC
Current assignee: BP PLC
Priority date: 1968-08-15
Filing date: 1968-08-15
Publication date: 1971-02-02
Anticipated expiration: 1988-02-02
Also published as: CY332A; MY6600015A; GB914568A

Abstract

A PROCESSS FOR THE PRODUCTION OF AN EDIBLE YEAST PRODUCT WITH A CONCURRENT DEWAXING OF A PETROLEUM FRACTION CONTAINING INITIALLY FROM 3 TO 45% BY WEIGHT OF N-PARAFFIN, SAID FRACTION FURTHER CONTAINING BRANCHED-CHAIN PARAFFINS, NAPHTHENES AND AROMATICS. SAID PROCESS PRODUCES A DEWAXED GAS-OIL PRODUCT THUS RENDERED MORE SUITABLE FOR INDUSTRIAL USE THROUGH A REDUCED PROPORTION OF N-PARAFFIN AND AN EDIBLE YEAST PRODUCT WHICH IS CULTIVATED AT THE EXPENSE OF THE N-PARAFFIN INITIALLY PRESENT.

Description

v 1'' 3,560,341 Umted States Patent 0 ,C PM... Feb. 2, 1971 3,560,341 PROCESS FOR THE REMOVAL OF STRAIGHT CHAIN HYDROCARBONS FROM PETROLEUM FRACTIONS Alfred Champagnat, Paris, and Jean Antoine Filosa, Lavera, France, assignors to The British Petroleum Company Limited, London, England, a British jointstock corporation No Drawing. Continuation of application Ser. No.

330,520, Dec. 16, 1963, which is a continuation-inpart of applications Ser. No. 131,470, Aug. 15, 1961, now Patent No. 3,193,390, and Ser. No. 228,728, Oct. 5, 1962. This application Aug. 15, 1968, Ser. No. 755,019 The portion of the term of the patent subsequent to June 21, 1983, has been disclaimed Int. Cl. C12c 11/00; C12d 13/06; A23j 1/18 US. Cl. 195-3 10 Claims ABSTRACT OF THE DISCLOSURE A process for the production of an edible yeast product with a concurrent dewaxing of a petroleum fraction containing initially from 3 to 45% by weight of n-parafiin, said fraction further containing branched-chain parafiins, naphthenes and aromatics. Said process produces a dewaxed gas-oil product thus rendered more suitable for industrial use through a reduced proportion of n-paraffin and an edible yeast product which is cultivated at the expense of the n-paraffin initially present.

This application is a continuation application of application Ser. No. 330,520, filed Dec. 16, 1963 (now abandoned), which is in turn a contination-in-part of application Ser. No. 131,470, filed Aug. 15, 1961 (which has issued into US. Pat. 3,193,390), and application Ser. No. 228, 728, filed Oct. 5, 1962, now abandoned.

Thi invention relates to a process for the removal of straight chain hydrocarbons, wholly or in part, from petroleum fractions in which they are contained and, more particularly, to a combined process for effecting said removal of hydrocarbons from petroleum fractions with the production of edible yeasts.

It is well known that certain petroleum fractions, particularly gas oils, contain straight chain hydrocarbons, mainly paraflins which are waxes and which have an adverse eifect upon the pour point of the fraction; that is to say, when these hydrocarbons are removed, wholly or in part, the pour point of the fraction is lowered. Usually the wax is removed by precipitation by means of solvents, the wax originally present in the fraction being recovered as such, that is, without conversion to more valuable products.

The petroleum fractions boiling below the gas oils, for example, heavy naphthas and kerosines also contain straight chain hydrocarbons which are potentially valuable for conversion to other products but hitherto, in general, utilisation of these hydrocarbons has been rendered difficult by the necessity of recovering these hydrocarbons from the petroleum fractions, in which they are contained, before they can be converted to other products.

It is also well known that food yeasts, suitable for consumption by cattle, or in some cases by human beings, are prepared using as starting materials carbohydrates, for example molasses, wood hydrolysis sugars and lyes obtained in the course of paper manufacture.

It is an object of the present invention to provide a process for the removal wholly or in part of straight chain hydrocarbons from petroleum fractions with the recovery of a valuable product based on the original straight chain hydrocarbon content of the petroleum fraction. It is a further object to provide a process for the dewaxing of a petroleum gas oil fraction with the production of edible yeast. Other objects will appear hereinafter.

According to the present invention there is provided a process which comprises cultivating a strain of yeast which is adapted to grow on straight chain paraffiuic hydrocarbons, in the presence of a petroleum fraction consisting in part of straight chain hydrocarbons and having a mean molecular weight corresponding to at least 10 carbon atoms per molecule, and in the presence of an aqueous nutrient medium; and in the presence of a gas containing free oxygen and separating from the mixture, on the one hand, yeast and, on the other hand, a petroleum fraction having a reduced proportion of straight chain hydrocarbon or which is free of said straight chain hydrocarbons.

The process of the invention is of particular value for the treatment of petroleum gas oil fractions which contain straight chain hydrocarbons in the form of waxes, since by the process of the invention a gas oil of improved pour point is obtained while the waxes are converted to a valuable product.

Usually the straight chain hydrocarbon will be present in the feedstocks according to the invention as paraffins; however, olefins may also be present.

It is an important feature of this invention that when cultivating yeasts in the presence of the feedstocks hereinbefore described under conditions favouring the growth of the yeasts as the expense of the straight chain hydrocarbons, the other hydrocarbons, for example isoparaffins, naphthenes and aromatics, are not metabolised or, at most, the proportion which is metabolised is very small. Furthermore, unlike conventional chemical process governed by the law of mass action, the rate of removal of straight chain hydrocarbons is not substantially reduced as the proportion of these hydrocarbons in the overall mixture of hydrocarbons decreases (except, of course, in the very final stages of removal). Thus, when desired, the percentage conversion of straight chain hydrocarbons which is achieved can be maintained at a value approaching 100% without necessitating a very disproportionate expenditure of content time to achieve small improvements. Furthermore, in a continuous process, this high percentage conversion can be achieved without resorting to the use of a long reaction path.

By the application of this process under conditions which limit the metabolisation of the straight chain hydrocarbons it is possible to operate with the removal of only a desired proportion of these hydrocarbons.

Suitable feedstocks to the process of the invention include kerosine, gas oils and lubricating oils; these feedstocks may be unrefined or may have undergone some refinery treatment, but must contain a proportion of straight chain hydrocarbons in order to fulfil the purpose of this invention. Suitably the petroleum fraction will contain 3-45 by weight of straight chain hydrocarbons.

Preferably when a yeast is employed this is of the family Cryptococcaceae and particularly of the subfamily Cryptococcoideae; however, if desired there may be used, for example, ascosporogeneous yeasts of the subfamily Saccharomycoideae. Preferred genera of the Cryptococcoideae subfamily are Torulopsis (also known at Torula) and Candida. Preferred strains of yeast are as follows. In particular it is preferred to use the specific stock of indicated reference number; these reference numbers refer to CBS stock held by the Central Bureau vor Schimmel culture, Baarn, Holland and to INRA stock held by the Institut National de la Recherche Agronomique, Paris, France.

Candida lipolylica Candida pnlcherrimaCBS 6l0 Candida util is Candida utilis, Variati major-CBS 841 Candida trpicalisCBS 2317 T orzdopsis c0llicul0sa-CBS 133 Hansennla an0ma[aCBS 110 Oidium lactis Neurospora sitophild Mycoderma cancoillote-INRA; STV 1 1 Of the above Candida lipolytica is particularly preferred.

A suitable nutrient medium for yeasts has the composition:

Grams Diammonium phosphate 2 Potassium chloride 1.15 Magnesium sulphate, 7H O 0.65 Zinc sulphate 0.17 Manganese sulphate, lH O 0.045 Ferrous sulphate, 7H O 0.068 Tap water, 200. Yeast extract 0.025

Distilled water (to make up to 1000 ml.)

When starting with a fresh stock of the yeast it will usually be necessary to adapt the yeast to assimilate carbon from hydrocarbons and to use an inoculum of the adapted yeast for the process of growth according to the invention. However these yeasts, when cultivated on an aqueous mineral medium containing the appro priate nutrient elements, grow with difficulty because the petroleum fractions do not contain the growth factors which exist in molasses and Wood hydrolysis sugars, for example.

The growth of the yeasts used is favoured by the addition to the culture medium of a very small proportion of extract of yeast (an industrial product rich in vitamins of group B obtained by the hydrolysis of a yeast) or more generally of vitamins of group B and/ or biotin. This quantity is preferably of the order of 25 parts per million with reference to the aqueous fermentation medium. It can be higher or lower according to the conditions chosen for the growth.

The growth of the yeast takes place at the expense of the petroleum fraction with the intermediate production of bodies having an acid function, principally fatty acids, in such manner that the pH of the aqueous mineral medium progressively diminishes. If one does not correct it the growth is fairly rapidly arrested and the concentration of the yeast in the medium, or cellular density, no longer increases so that there is reached a so-called stationary phase.

Preferably therefore the aqueous nutrient medium is maintained at a desired pH by the step-wise or continuous addition of an aqueous medium of high pH value. Usually, and in particular when using Candida lipolytica, the pH of the nutrient medium will be maintained in the range 3-6 and preferably in the range 45. Suitable alkaline materials for addition to the growth mixture include sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate and ammonia, either free or in aqueous solution.

The optimum temperature of the growth mixture Will vary according to the type of yeast employed and will usually lie in the range 25-35 C. When using Candida Zipolytica the preferred temperature range is 2832 C.

The take-up of oxygen is essential for the growth of the yeast. The oxygen will usually be provided as air. In order to maintain a rapid rate of growth the air, used to provide oxygen, should be present in the form of fine bubbles under the action of stirring. The air may be introduced through a sintered surface. Preferably however there is used the system of intimate aeration known as vortex aeration.

It has been found that by the use of yeast of the strain Candida lipolytica in a process according to the invention in which aeration is effected by vortex aeration, a high growth rate is achieved whereby the generation time lies in the range 25 hours and the cell concentration is increased by a factor of up to 12 in two days.

At the end of the growth one obtains an emulsion which contains yeast and nonmetabolised hydrocarbons in a continuous aqueous phase. This emulsion is broken down by a first centrifuging in the presence of a surfactant. One obtains:

(a) On the one hand a pasty phase of yeast cells impregnated with hydrocarbons and aqueous medium.

(b) On the other hand an aqueous phase and the greater part of the phase of hydrocarbons which will be separated subsequently.

The pasty phase of yeasts is subjected to successive alternate washing and centrifuging stages in the presence of a surfactant until these yeasts are free from hydrocarbons, the last washing being carried out with pure water. The yeast is then dried under conditions which render it capable of assimilation.

The hydrocarbon phase and the aqueous phase (to which one adds the wet hydrocarbon phases coming from subsequent centrifuging of the yeast) are treated by decantation or centrifuging to separate the hydrocarbons and the aqueous medium.

The process may be carried out batchwise. However if desired, any one or more of the stages herein described may be carried out in continuous manner.

The treated petroleum fractions will be very suited to a number of different uses, depending on boiling range and other characteristics. Thus the kerosenes may be employed as aviation jet engine or gas turbine engine fuels; the heavy gas oils are suitable as heavy diesel fuels. Also there may be obtained oils suitable for use as refrigerator oils or as transmission fluids.

The invention is illustrated but not limited by the following examples.

EXAMPLE 1 The feedstock was a heavy gas oil having the following characteristics:

The yeast employed was a strain of Candida lipolytica previously cultivated on a malt sugar medium and adapted to withdraw its carbon from hydrocarbons. This adaptation was carried out by preparing an inoculum by the method now described:

Preparation of the inoculum A culture of Candida lipolytica is made in sterile 250 ml. conical flasks. These are open to the air and contain 50 ml. of a mineral medium together with 5/10 ml. of the heavy gas oil described above. The mineral medium has the following composition:

Monopotassium phosphate7 gm. Magnesium sulphate-0.2 gm. Sodium chloride-0.1 gm. Ammonium chloride-2.5 gm.

Tap water (trace elements) ml. Difco yeast extract1 ml.

made up to 1000 ml. with distilled water.

This culture is incubated for 3 days at 30 C. with (b) A limpid phase of aqueous mineral medium. mechanical agitation. (c) A Wet hydrocarbon phase.

ml. of this culture are then taken and added to a The pasty phase containing the yeast cells is then washed flask containing the same quantities of the same mineral with water containing 0.25 part per mil of the same surmedium and hydrocarbons. The incubation is continued factant. Two washings and two centrifugings are sufiicient for 3 days with agitation. These same operations are 5 to obtain yeast which is free from hydrocarbons. Finally repeated 4 or 5 times. the yeast is washed with pure water at 60 C. to eliminate Two sterile 2 litre toxin flasks, each containing 1 litre the surfactant left in the yeast and it is then centrifuged. of the above mineral medium to which ml. of heavy The product thus obtained is dried at 80 to 90 C. in

gas oil have been added, are seeded by means of 20 10 a ra id current of air. mL/Iitre of an inoculum coming from the preceding culture. This culture is incubated for 36 hours at 30 C. Recovery of the dewaxed heavy gas oil with mechanical agitation. The 2 litres of culture are To the Wet hydrocarbon phase from the first centrifugcentrifuged at 30 C. and the yeasts recovered in the ing, is added the wet hydrocarbon phases from the two centrifuge cups constitute the inoculum necessary for subsequent centrifugings and the mixture is allowed to one experiment. settle at 30 C., until the water which it contains separates Subsequent stages were carried out by the method now out. (More satisfactorily this step is carried out by cendescribed. trifuging.)

The table below gives the numerical results obtained in this experiment:

Initial cellular density-0.800 gm./ litre Final cellular density4.76 gm./ litre Growth time11 hours Culture of Candida lipolyrica on heavy gas oil There is introduced into a fermenter, equipped with an aeration system of a type which forms a vortex in the mixture, 1 litre of the same mineral nutritive medium as described above (containing 1 ml./litre of yeast extract)' The PH is regulate? to at i beginning 5 Production of yeast per litre of culture medium and the experiment and is maintained at this figure during per hour. the culture by the addition of monopotassium phosphate.

The air injection is started up at the rate of 50' litres/ 4.760.80 0 360 H h hour/litre of the medium and the temperature is main- 11 1 re/ our tained at C., and periodically distilled water is added 30 to compensate for evaporation losses. 0-360 gm/ 6/ hour The fermenter is then seeded with 800 mg. of the Yield of yeast in relation to the gas inoculum whose preparation is described above, and the gas oil is introduced in four stages in quantities in an ex- 4.76-0.80 ponentially increasing series, so as to reach in all 25 ml./ 25 0.866 18% by Weight htre of medlum' Yield of dewaxed gas oil-82% by weight The incubation is stopped when the cellular density (concentration of cells) remains constant, that is to say when the stationary phase has been reached. The cellular EXAMPLE 2 density is measured by taking periodical 25 ml. samples of 40 An inoculum was re and b the method described the culture, the cells of which are filtered, washed until in Example 1. In placepofghe feeditock used in Example 1 Pour point dewaxed gas oil- 40 C.

the NH ions disa ear and dried. Their content of nitrogen is e stimated the Kjeldahl method. Measurements $32 32? employed the gas 011s descnbed m the followcarried out previously on pure dry candida lipolytica gave The method of culture and product Separation was as a nitrogen content of 5 Filom the mtrogen content described in Example 1 except in respect of the scale of of the test sample taken it is possible to deduce the cellular the operation Thus 30 litre fermenters were p y density of the culture at the moment the sample was containing 20 litres of the nutritive medium and in each taken case starting with 40-50 grams of inoculum.

Recovery of the yeasts Also, in place of monopotassium phosphate, N/ 1 ammo- To the emulsion formed there is added 0.25 per mil by nium hydroxide aqueous solution was employed to regu- Weight, reckoned on the aqueous phase, of the cationic late the pH.

TABLE Feedstock Reference A B C D E F G Feedstock Feedafter stock desulphualter risation Straight run Heavy terroby hydro- Nature of gas-oil Zarzaltine Irak Kuwait Irak Zarzaitine fining fining Ch t ti f s-oil bet re tr atment, distillation:

i i ti a l li l O 0 e 305 224 198 223 178 305 223 50%, C 327 348 361 366 380 327 360 Final B.P., C. 351 390 400 400 400 351 400 Four point, 0.... +8 +11 +17 +22 +26 +6 +21 Content of normal paratfins percent by weight 3. 3 13. 2 8. 8 14 11. 6 13. 3 12 Characteristics of gas-oil after treatment:

Pourpoint, "C "d ...g it.. i azb.. 5 0 16 +3 -25 -9.3

' nta 60111 'mal 3TB. 1113 11 me a OISE Y il rgighti 3 00.3 0.18 0.5 0. 87 1. 4 3. 4 0. 1 1, 5 Yield of yeast, based on feedstock (by weight) 12. 5 13. 2 8. 1 7. 8 8 16 11. 5

surfactant, ammonium stearyl-trimethyl chloride and the EXAMPLES 3 To 8 pH is adjusted to 8 by the addition of caustic soda. The discontinuous centrifuging of this mixture gives: An inoculum was prepared by the method described in (a) A pasty phase of yeast cells impregnated with hy- Example 1. The method of culture and product separadrocarbon and aqueous medium. tion was as described in Example 1 except in respect of the scale of the operation which was the same as described in Example 2.

The results obtained with different strains of yeast and the characteristics of the feedstock used are recorded in the following table:

discontinued and the product treated as described in Example 1.to recover separately the yeast and the treated gas oil.

The species of yeast employed and the improvement in cloud point and pour point obtained in the gas oil are Example No.

Origin of gas-oil Hassi Irak Irak Irak Irak Messaoud Kuwait Strain of yeast used Tomla Candida Toralopsis Hansenala Candida Oidiu'm atilz's tropicalis collicalosa anomala palcherina lactis Characteristics of gas-oil before treatment, Distillation ata: Initial B.P., C 224 224 223 217 235 198 50%, C n 348 348 366 200 294 361 Final B.P C. 390 390 400 302 381 400 Pour point, C +11 +11 +22 4 -1 +17 Content of normzfil paraffins, perceint t 13. 2 13. 2 14. 2 9 3. 2 8.8 Characteristics as-oi a ter trea men Pour point, 3 -24 -20 15 26 30 20 Content of normal paraflins, percent by we glit. 0.8 0.6 1 O. 0 0. 7 l. 2 Yield of dried yeast, based on feedstock, by weight." 14 13 8. 2 8. 9 8. 2

EXAMPLE 9 The feedstock was a heavy gas oil derived from Irak petroleum having the following characteristics:

Density at 15 C./4 C.O.878 Distillation Initial boiling point-220 C. Percent at 250 C.-3 Percent at 360 C.50 Final boiling point405 C. Cloud point+21 C. Pour point+l7 C. Paraffins percent by weight-12.8

shown in the following table (initial pour point +17 C.; initial cloud point +21 C.):

Particulars of the growth and analysis of the recovered yeast are given in the following table (initial cell density: 1 gram/litre).

Final Yield, Composition of yeast cells cell percent Mean density, of gas Free g neration gram/ oil N Lipids, tats,

Genus, specie time, hours litre treated percent percent percent percent Candida, species 8 16 8 9 47 9 4 Candida, Zipolytica 7 13 6. 5 9 47 12 0 Candida, pulcherrima-.. 10 5 7. 3 47 7 0. 6 M ycoderma, cancoillota. 7 16 8 8 48 14 1. 3 Hansen Ma, an0mala 7 16 8 7. 3 45 15. 5 1 Torulopsis, collicalosa 5 16 8 7. 7 4. 1 Oidiam, lactis 12 10 5 7. 3 45 42 2. 5

The aqueous nutrient medium had the following composition:

Grams Diarnmonium phospate 2 Potassium chloride 1.15 Magnesium sulphate, 7H O 0.65 Zinc sulphate 0.l7 Manganese sulphate, 1H O 0.045 Ferrous sulphate, 7H O 0.068 Tap water 200 Yeast extract 0.025

Distilled water (to make up to 1000 mls.).

A series of seven different yeasts were separately grown batchwise on this feedstock, the conditions in each case being as follows:

litres of the aqueous nutrient and 75 grams of the gas oil feedstock were stirred wtih 15 grams of the yeast in a litre fermenter under conditions of vortex aeration with introduction of air at the rate of volumes per volume of liquid/hour. Gas oil was added progressively to the fermenter according to the rate of growth of yeast until a quantity of 3 kilograms was attained, the runs proceeded again until there was no more significant increase in cellular density-e-then the aeration and agitation were The yeasts as herein described are well suited for the metabolisation of the straight chain hydrocarbon components of petroleum fractions having a mean molecular weight corresponding to at least 10 carbon atoms per molecule despite the presence in the fraction of nonhydrocarbon components such as sulphur compounds and it has not been found necessary to remove such components prior to treatment in accordance with the invention. Nevertheless it will be necessary to ensure the absence of extraneous materials used in refining which are injurious to yeasts, at least up to and including the growth period. Thus it should be noted that furfural must be excluded from the feedstock, also bacteriostatic agents such as phenols and quaternary nitrogen compounds. Certain metals are also injurious and should be kept from contact with the yeast; typical of such metals are copper, lead and mercury.

We claim:

1. A process for the removal, at least in part, of straight-chain paraffinic hydrocarbons from a petroleum fraction having a mean molecular weight corresponding to at least 10 carbon atoms per molecule and containing 3-45% by weight of straight-chain parafiinic hydrocarbons said fraction further containing naphthenes, aromatics and branched-chain paraffinic hydrocarbons, and the concurrent production of an edible yeast, which comprises cultivating a strain of yeast capable of consuming straight-chain paraffinic hydrocarbons and which has been adapted to grow on straight-chain paraffinic hydrocarbons, in the presence of said petroleum fraction, an aqueous nutrient medium, and a gas containing free oxygen, and after growth of the yeast, separating from the mixture a yeast-containing fraction, an aqueous phase, and a petroleum fraction having a reduced proportion of straightchain paraffinic hydrocarbons as compared with the proportion of said hydrocarbons present in said fraction initially, and containing substantially all of the naphthenes, aromatics and branched-chain paralfins present in said fraction.

2. A process according to claim 1, wherein the pH value of said aqueous nutrient medium has a predetermined value within the range 3 to 6.

3. A process according to claim 1, wherein the pH value of said aqueous nutrient medium is maintained within the range 4 to 5.

4. A process according to claim 1, wherein the pH value of said aqueous nutrient medium is maintained within the range stated by the addition during the cultivation of the yeast of an alkaline material selected from the class consisting of sodium hydroxide, potassium hydroxide, monopotassium dihydrogen orthophosphate, and ammonia either free or in aqueous solution.

5. A process according to claim 1, wherein said petroleum fraction consists of a gas oil.

6. A process according to claim 1 wherein said gas oil boils within the range 178 to 405 C. and contains from 8.8 to 18% of straight-chain paraffinic hydrocarbons.

7. A process for the removal, at least in part, of straight-chain paraffinic hydrocarbons from a petroleum fraction, having a mean molecular weight corresponding to at least 10 carbon atoms per molecule and containing 3-45% by weight of straight-chain paraffinic hydrocarbons and said fraction further containing naphthenes, aromatics and branched-chain paraffinic hydrocarbons, and the concurrent production of an edible yeast, which comprises cultivating a strain of yeast capable of consuming straight-chain paraffinic hydrocarbons and which has been adapted to grow on straight-chain parafilnic hydrocarbons, in the presence of said fraction, an aqueous nutrient medium, and a gas containing free oxygen, and after growth of the yeast, separating from the mixture a yeastcontaining fraction contaminated with hydrocarbons, an aqueous phase, and a petroleum fraction having a reduced proportion of straight-chain parafiinic hydrocarbons as compared with the proportion of said hydrocarbons present in said fraction initially, and containing substantially all of the naphthenes, aromatics and branched-chain paraffins present in said fraction, treating said yeast-containing fraction for the removal of the hydrocarbons therefrom, and drying the hydrocarbon-free yeast under conditions to yield an edible yeast product.

8. A process according to claim 7, wherein said aqueous nutrient medium has a pH value within the range 3 to 6 and wherein said pH value is maintained within said range by the addition to said medium during the cultivation of the yeast of an alkaline material selected from the class consisting of sodium hydroxide, potassium hydroxide, monopotassium dihydrogen orthophosphate, and ammonia either free or in aqueous solution.

9. A process according to claim 7, wherein said petroleum fraction consists of a gas oil.

10. A process according to claim 9, wherein said gas oil boils within the range 178 to 405 C. and contains from 8.8 to 18% of straight-chain paratfinic hydrocarbons.

References Cited Just, F. et al.: Branntweinwirtschaft 2:113115, 1948. Bruyn, 1.: Koninkl. Ned. Akad. Wetenschap, Proc Ser C, 57: 41-45, 1954.

40 LIONEL M. SHAPIRO, Primary Examiner U.S. Cl. X.R. 19528 mg?" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,560,341 Dated February 2, 1971 lnvenml-(a) Alfred Champagnat and Jean Antoine Filosa It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 32, "as should read at Column 6, line 30, cancel this line;

Column 7, line 48, "405C. should read 450C.

Claim 6, line 1, "1" should read 5 Signed and sealed this 16th day of November 1971.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSOHALK Attesting Officer Acting Commissioner of Pete