US2433363A - Process of reforming hydrocarbons - Google Patents

Description

Patented Dec. 30, 1947 PROCESS OFJREFORMING HYDROCARBONS Jacquelin E. Harvey, J1'.,Washington, D. 0., and Robert H. White, Jr., and Joseph A. Vaughan, Atlanta, Ga., asst'gnors of one-half to Jacquelin E. Harvey, Jr., Washington, D. 0., and onehalf to SouthernWood Preserving Company, East Point, Ga., a corporation of Georgia No Drawing. Application October 7, 1944,

7 Serial No. 557,724

The instant invention relates to the production of toxic oils employable as fungicides, insecticides, and for any other service to which toxic oils may be put.

This application is a continuation-in-part of our application Serial No. 467,416, filed Novem ber 30, 1942, for Method of providing a new oil, copending herewith, and which is now abandcned, as to allmatter common to the two applications.

More especially the instant invention relates to the production of toxic oils from mixtures of petroleum fractions characterized by ring structure content. Among such starting materials may be mentioned mixtures of petroleum fractions characterized by ring structure content re covered from petroleum fractions by well known extraction methods including extractive distillation and solvent extraction. Also may be mentioned mixtures of petroleum fractions characterized by ring structure content as flowing from thermal and/or catalytic treatment of certain petroleum fractions which includes petroleum fractions having ring structures induced in the course of thermal and/or catalytic treatment, as for example having ring structures induced in the course of one or more thermal and/or catalytic treatments of unusual length, as for example; for periods of from 1-10 hours or more.

An object of the instant invention is the production of toxic oils from the aforenamed pctroleum fractions or others whereby to provide oils of the preservative type, as for example preservative wood impregnants conforming to specifications extant or acceptable to the trade con-- Yet another object of the instant invention isv the provision in the overall beneficiated material cf t at percentage of newly induced fractions bo ling below 210 C. which is conducive to the inchiction of toxicity in other fractions-of the material under treatment. 4 Jv l 9 Claims. (01. 196-49) Another object of the instant invention is the induction of additional toxicity into fractional parts of the once beneficiated'startingmaterial under specific controls of process variables.

A specific object of the invention is the transformation, reformation; conversion and/ or modification of relatively high boiling petroleum oils characterized by structures of cyclic structure content having inherent but inhibited toxicity whereby to provide said structures of cyclic structure content as materials exhibitinga more pronounced toxic value.

Still another object of the present invention is the conversionof substantially non-toxic petroleum type aromatics into materials more closely approaching the highly toxic coal tar aromatic type, as more fully set forth in the followingf p Still 'ano therobject of the presentinvention is the conversion of petroleum type aromatic material olf a relatively narrow boiling range into materialof relatively wide boiling range more closely approaching the characteristicsof coal tar aromatics, by a process wherein the control isevidenced by the percentage of newly formed aromatics found in certain fractions of the beneficiat'ed material.

In the past "wood preservative oils of the high temperature coal tar derived type have been employed in quantities greatly exceeding the total of all other wood preservative oils. From the standpoint of availability of said coal tar as the parent product of wood preservative oils, it is annually produced in this country under normal conditions to the extent of five hundred million to six hundred million gallons. This quantity of coal tar is capable of yielding an amount of highly. effective wood preservative oil which would make this country self sufficient in its wood preservative requirements. However, due to the fact that when a Wood preservative distillate (creo sote) is recovered from coal tar there remains in the still a residue (pitch) which, at best, is a low priced product and which, at worst, is a seriously distress product tothe end that at times been imported into -this-eountry.- That such a situation should obtain is apparently a paradox in that we annually produce a quantity of high temperature coal tar which if processed to yield creosote would make us self suflicientin. that requirement. A survey of this paradox is fully'outlined in an address given by no less an authority than S. P. Miller, technical director, The Barrett Company, 40 Rector Street, New York city, be

fore the Franklin Institute;.Philadelphial'Penn sylvania. in December, 1932. n The economics of coal tar have not materially changed: ince that date. ;I I I In view of the apparent inability r the eel tar industry to provide national needs of wood preservative oils, a strong incentiveg'is givenito groups processing other types of. oil to invade tl e lucrative wood preservative market. At the 'pres: ent time many types of aromatic oils are produced by the petroleum industry, and the high-boilingdils of aromatic content produced by this industry have for several years been tested for their .wood preservative efficiency. i By-the term petroleum aromaticfas used herein and in the appended claims is meant to include mixtures of petroleum-fractions characterized by cyclic content and includes specifically various forms and types of naphthenes found in various mixtures of petroleum fractions, as for example monocyclic and polycyclic naphthenes.

The so-called petroleum aromatics; whichineludes the monocyclic and polycyclic naphthenes and. unsaturated cyclic hydrocarbon fractions have in the past been produced in very large guan- In the foregoing tabular data P. M. C. C. means Pensky-Martin Closed Cup; C. O. C. means Cleveland Open Cup.

Upon evaluating the foregoing oil for its toxicity to wood destroying fungi (Madison 517), it was found that this oil did not totally inhibit the growth of the fungi named at a concentration of up to and including Madison 517 is a strain 'of therungus Fomes ahnosus.

It is nowdiscovered that the oil above named or other oils of .cyclic structure content produced tities. However, very little work has been done on these materials. Such a fact'isborne outon page 667, fReactions of Purel Hydrocarbons, Gustav Egloff," Reinhold Publishin i Corporation, 330 West 42nd Street, New York city, whichstates Despite the fact that naphthenes orcycloparafiines are available in enormous quantities} as shown by an estimate of 100,000,000 barrels present in the 1.498,000,000 barrels of crude oil which was the worlds production in 1934, comparatively little work ofapyrolytic nature has been performed on individual naphthene hydrocarbons'or the cycloolefins. i Q Several oils of cyclic content produced by the petroleum industry have been inspected for their toxicity to .wooddestroying fungi, amongfwhich may be mentioned a high boiling.v oil .of .cyclic structure contentproduced (1940).at the Wood River Refinery of the Shell Oil Company. and which has the following inspection:

Gravity Flash, P.-M. 0.0., "F 295 Flash; C; O. C., F 290 Fixed carbon, per cent 4 9 Pour point, F 1 10 B.S:& W. by VO1 4; 0.1 S. U. -Vis. 100 F 151 S. U. Vis. 210 F; 41 Vis; 77 F 3415 Carbon residue 6.8 Per; cent aromatics and unsaturate 82.4 801. in CS2 V 99.8 Loss 50 grams. 5 hours 325 F 8.9 Residue of 100 pene., per cent 37.5 A. S. T. M. distillation: H

I. B. R, F 518 10% Rec. F 565 20% Rec. F 589 Rec. F 614 v 40% Rec. F 637 Rec. F 660 60% Rec.-@;F max .675

by thepetroleum industry can be increased in toxfi'eity' accordance with the process of the instant invention.

According to the instant invention oils of cyclic structure content produced by the petroleum industry are reformed, transformed, modified and/0r converted to oils of a more toxic nature havingcharacteristics acceptable to consumers of wood preservative impregnant and/or conforming to wood preservative specifications extant.-

We have discovered that if the starting materials named are subjected to a thermal treatment at a temperature of 325550 C., and if the treatment is so controlled as to provide in the materials of the end product boiling between 210 C.- and 355 C. a percentage of aromatics not substantially less than about 70%, the reformed, converted and/or modified oil boiling between about 210 C. and 355 C. will have a toxicity to wood destroying fungi approaching or equalling the toxicity of high temperature coal tar or its derivatives, provided (1) the specific gravities of the overall fractions within the 210-355 C. cut of the beneficiation fall about within the limits shown; in the appended tabular data:

Fractions Low Limit High Limit Or- (2) the specific gravities of the aromatics in the; fractions of the 210-355 C. out of the beneficiated material fall about within the limits shown in the appended tabular data:

The-followingexamples will serve to illustrate several modes of practicing the present invention.

Example 1.-A mixture of petroleum fractions characterized by a substantial content of petroleum type aromatics and having but slight growth inhibition to wood destroying fungi, as for example, the Shell product shown in the foregoing tabular data, is charged to a high pressure autoclave and brought up to a temperature of 500 C. where it is held for a period of 30 minutes. The pressure reaches a maximum of 1275 pounds per square inch. The beneficiated material is cooled and inspected, and is found to have (1) newly formed materials boiling below 210 C., and (,2) an overall toxicity approaching or equalling thetoxicity'of certain high temperature coal tar wood preservatives.

Inspection of the beneficiated material discloses mattersshown in the appended tabular data:

All four fractions about 0.50.

The total inhibition point (toxicity test) above noted is expressed as the percent of the preservae tive by weight of medium on which tested and required to totally inhibit the growth of the fun-' gus under test. The toxicity test isqfully de-= scribed on pages 34 to 43 of the 1933 Proceedings of The American Wood Preservers Association.

The Shell oil which was the starting material of the present example had an unsatisfactory toxicity to wood destroying fungi due to the toxicity diluents that were attached .to the aromatics, which toxicity diluents for working purposes may be considered the side chains attachedto the ring nuclei. We have found by controlling the process variables as to provide in the 210-355 C. out of the beneficiated material (.1) specific gravities in aromatics in fractional parts of said out which fall between the limits previously stated, and/or (2) specific gravities in overall fractions of thenamed out which fall between the limits named in the foregoing, that this is a guarantee of, and a test for, the induction of toxicity to wood destroying fungi in the named beneficiated out which approaches orequals thetoxicity of certain high temperature coal tars or theirpreservative derivatives. The controls above named, either or both, are practices by which sufficient toxicity diluents may be removed from the highly toxic ring nuclei to insure acceptable toxicity to the wood preserving industry.

By processing the Shell oil in the manner above named, a crude material whose total inhibition point to the growth of wood destroying fungi was in excess of is at least partially converted into a material which approaches or equals the toxicity of conventional coal tar creosote.

The beneficiated material is fractionated to recover a wood preservative impregnant of induced toxic properties having 2% distilling below 10 0., more than 1.5% distilling above 315 0. and residue above 355 C. It is of especial importance that the newly formed preservative oil has at least about -20% residue above 315 C. for it is on these high boiling fractions, among others, that our new oil depends for its permanency.

The materials of induced toxic properties as flowing from the process carried out under the controls above disclosed have at times substantial residual matter above 355 0. and may be used in toto as a wood preservative, or in the event it is desired to provide a wood preservative impregnant complying with specifications extant or of consumer preference, a wood preservative may be segregated from the overall beneficiated oil as a stabilized residual, distillate or extract, and in the event the extract has non-permissible low boiling ends, the extract may be stabilized to the desired necessar extent by removal of low ends,

As illustrative of wood preservative impregnants of the oil derived type that have met with consumer acceptance .and which may be segregated from the overall beneficiated material of the in tani process. t following tabu de ention Woon PRESERVATIVE IMPREGNANTS Specifications 1. American Wood Preservers Association a. Up to 210 0., not more than 5% a b. Up to 235 0., not more than 25% 2.- American Wood Preservers Association a 0.. Up to 210 0., not more than 1% 17. Up to 235 0., not more than 10% 0. Up to 355 0., not less than 3. 1 American Wood Preservers Association a. Up to 235 0., not more than 1 b. Up to 300 0., not more than Mi 0. Up to 355 0., not less than 45% 4. American Wood Preservers Association 0.. Up to 210 0., not more than 8% r a b. Up to 235 0., not more than 35% 5. American Wood Preservers Association a. Up to 210 0., not more than 10% b. Up to 235 0., not more than 40% 6. American Wood Preservers' Association (1. Up to 210 0., not more than 5% 1). Up to 235 0., not more than 15% 7. Prussian Ry.

' 0.. Up to 150 0., not more than 3% 5. Up to 200 0., not more than 10% .c. Up to 235 0., not more than 25% 8; National Paint Varnish 8; Lacquer Association #220 i a. 5% at 162 C. b. 97%at 270 0. '9. Southern Pine Shingle Stain Oil 0.. 5% at 137 C. I b. at 257 0. Neville Shingle Stain Oil a. LE. P., 150 C. t. 5% at 205 0. c. 95% at 292 0. v 11. Carbolineum 270 0., I. B. P.

I Example 2.--A .petroleum aromatic oil having 4% of low ends below 235 0., and boiling preponderantly between 235 0. and 355 0. is

'The 210-355 C. out of the treated oil has the fo lowing inspection:

- on npeci c Percen age hibition Gravity of of Aromatics Point) Fraction A.ll four fractions 0.050.

.a'I'he 210-355 0. fraction of the beneficiation issegregated therefrom by fractional distillation to provide a highly toxic preservative wood impregnant as a distillate.

By providing in the beneficiated material the overall specific gravities noted in fractional parts of the 210-355 C. out, a guarantee is secured that su llicient reforming, cracking, modifying and/or qpnrsrtir bas e a o s e to ns r he 7 materlals 'boiling' betw een"210 C. and 355 C. having a toxicity comparing favorably with that found in high temperature coal tar wood preservatives.

Example 3.When processing the starting material as disclosed in Examples 1 and 2, it is found that the materials boilingbelow and abov 270 C. have a relatively high-and low toxicity, respectively. It is of especial importance that the materials boiling above 270 C. have as'high a toxicity as possible for the reasorrthat these materials have a toxicity blanketing effect on the lower boiling materials of highest toxicity. We have discovered that by retreating the once processed materials boiling above 270 C. that additional toxicity may be induced. A typical practice of this phase of our'invention is hereinafter outlined.

The'starting material is subjected to a temperature of 480 for a period of 45 minutes while maintaining apressure of 750 pounds per square inch. The beneficiated material is cut at 270 C. to'provide 'a low boiling portion of relatively high-toxicityand a high boiling portion of relatively lowtoxi,cit-y.- The high boiling portion is subjected to a temperature of 475 C. for a period of 30 minutes at the pressure above named. The onceand-twic treated materials are commingled' and are found to :have inthe materials boiling between210 (Land 355C. a'percentage of aromatics in excess of 70%. The specific gravities of the aromatics in question fall between the limits shown in foregoing tabular :data, and the specific gravities ofoverallafractions-in the 210- 355 C. out fall within thelimits previously noted. A wood preservative impregnantboiling preponderantly between 210 (band-355 G. and with 25% residue above 315 C. is-segregated from the commingled benefication; and subsequent inspection reveals the fact that it has a-toxicity acceptable to the wood preserving industry, that is to say, a toxicity closely approaching that found in high temperature coal tar wood preservatives.

. Instead of cutting the primary benefication at 270 C., the cut may be made at other temperatures, say at 285 0., 300 C. or above. The high boiling portion is then treated at a temperature falling within th disclosed limits.

We have found when practicing a two-step process as disclosed in the instant example that by providing a total treatment period. of not in excess of about two hours, acceptable toxicity approaching or equalling that of high temperature coal tar preservative products, may beprovided. As illustrative of this mode of practice, a period rYot'ifixcess of one hour may be employed in the primary step, and a period not in excess of 30' or 40 minutes, more or less, may be employed in the secondary step which retreats the higher boiling segregation. Such treatment periods have been found to give the desired results, although other periods of treatment for the two steps, the total of which falls below about two hours, may be practiced.

Example 4.-A petroleum aromatic oil distilling 3% below 270 C. and with 50% residue above 355 C., having an aromatic and unsaturated content of over 70%, a specific gravity of aromatics of 1.0166 in the 270-315 C. fraction and a specific gravityof aromatics of 1.0256 in th 315-355 C. fraction is subjected to a temperature of 460 C. while under a pressure of 1000 pounds per square inch for a period of one hour. Thereafter the heat treated material, without substantially lowering the-temperature, is held under a pressure of 400 pounds per square inch for a period of 30 minutes. At the end of the named second period the benefication is cooled and inspected and is found to have in excess of 70% aromatics in the materials boiling between 210 C. and 355 C., and the fractional parts of the 210-355 C. out have aromatics whose specific gravities fall within the limits noted in the tabular data previously shown.

The benefication which has newly induced fractions boiling below 210 C. is fractionally distilled to provide a distillate of the wood preservative type boiling substantially between 210 C. and 355 C. A toxicity evaluation of the wood preservative type distillate shows that its toxicity closely approaches that of high temperature coal tar creosote.

In the two-step operation disclosed in the instant example we have found that a period of not in excess of about one hour is suitable for the primary step. Dependent upon the temperature selected within the range herein disclosed, periods of 20, 30 or 40 minutes, more or less, are acceptable. In the secondary step of this mode of practicing the instant invention, we have found that a period not in excess of about one hour is sufficient to induce the desired qualities. When employing in the first stage a relatively high temperature Within the range herein disclosed, and a relatively high pressure drop in the second stage, a relatively short period of treatment in the second stage will provide the desired percentage and specific gravity of aromatics.

. The relationship of the high and low pressure steps may vary over relatively broad limits, as for example, the first step may be carried out at Very high pressures and the second step at a pressure only slightly above atmospheric. On the other hand, if a relatively low pressure is employed in the first and high pressure step, say a pressure of about 300 pounds per square inch, then atmospheric or sub-atmospheric pressure may be employed in the second step.

Viewed broadly, this phase of practice of our invention is not circumscribed by any definite pressures in the high and low pressure steps, but rather turns on employing a relatively high pressure in the first stage and a relatively low pressure in the second stage.

Example 5.The Shell petroleum aromatic oil noted'previously is subjected to a, temperature of 465 C. 'at a pressure of 900 pounds per square inch for a period of 40 minutes. Thereafter the partially beneficiated material is subjected in entirety to a temperature of 500 C. for a period of 20 minutes. The beneficiated material is cooled and inspected and is found to have newly formed fractions boiling below 210 C., and in the materials boiling between 210-355 C. in excess of aromatics. The specific gravity of aromatics in fractional parts of the 210-355 C. out of the beneficiation fall between the limits noted in the tabular data previously shown. A toxicity evaluation of the materials boiling between 210-355" C. indicate that only about 0.5% is required for total inhibition of growth of wood destroying fungi.-

We have found that when practicing our invention with a relatively low temperature step and a subsequent relatively high temperature step, the temperatures in both steps being selected between the limits of about 325-550 C., optimum conditions are secured by providing a period of treatment in each step of not in excess of about one hour; If relatively" high temperatures'within the limits named are employed in the twostep process of dissimilartemperatures; relatively short periods in the two steps are possible; and we have found that under Very severe thermal conditions within the limits named, periods of 10, or minutes in each step mice to induce the desired characteristics.

Viewed broadly, this phase of our invention is not circumscribed by any definite time period, other than the upper limit, but rather turns on the correct coordination of a relativelylow temperature step and a relatively high temperature step, whereby to provide the desired percentage and specific gravity of aromatics and/or desired percentage of aromatics and specific gravity" of overall fractions in the end product, which thing or things in turn insure induction of toxicity ap proaching or equalling that of high temperature coal tar WOOd' preservative impregnants.

When treating certain mixtures of petroleum fractions that have a relatively low petroleum aromatic content we have found the operational procedure as outlined in the following exampleof especial merit.

Example 6.A recycle oil containing'lesst than 30%, petroleum aromatics is sublectedto' the processing conditions disclosed in Example: 1. Upon inspection of, the beneficiated. material it. is found that although the specific gravity of; the aromatics fall within the limits previously disclosed, the total percentage of aromatics is less than 70 The beneficiated material is then extractedwith liquid sulfur dioxide and therafiinate discarded. The extract isthen stabilized to provide a residual as an oil of the wood preservative type boiling preponderantly between2lQ-355jC and whichhas an overall total inhibition point to the growth of wood destroying fungi of. not in excess of about 0.5%.

Although liquid sulfur dioxide is shown as the extracting agent, it is-immediately obvious that other materials may be employed, as-for example furfural or the like. p

Instead of practicing the process in a once through treatment as disclosed in Example 1, especial toxicity induction benefits flowfrom dividing the beneficiation into-arelatively low boiling portion and a relatively high boilingportion; and subsequently retreating separately the two fractions. Thetwo fractions may be, treated at similar or dissimilar temperatures within the range previously disclosed. When they retreated fractions are commingled, it will be foundthat they have a toxicity in excess of the oncetreated material. t t h e In lieu of retreating both the high and low boiling portion, the low boiling portion may' be retreated and then commingled with the once treated high boiling portion to provide a comminglement having a toxicity in excess ofthe once treated'oil.

Another mode of practicing our invention re sides in treating the petroleum aromatic? containing oil in the presence of benzene; toluene;

thenpior example, treated asuin, Example 1;. The;

resultant alkylatedbenzene is then removed; Upon inspection, it will be found that the petro leumaromatic has a percentage of aromatics not lower than 70% and the specific" gravityof the aromatics in fractional part of the 210-355 G:

v 10 cut fall betweenthe limits noted in the tabular data previouslyshown. The commingling of parts of the petroleum aromatic with 50 parts of benzeneisfor purposes of illustration only; other percentages maybe used; When the feedstock consists of a; petroleum oil having a;v relatively lowpercentage of petroleum aromatics and unsaturates, it is advisable to first extract the on and thentreat according to any of the modes or practicing our process;

Example 7; Wehave found indications that the basic-reason whypetroleum aromatic have relatively littletoxicityis becauseoi the relative- 1y" non-toxic materials (side chains) attached to the ring nucieiwhichlower water solubility of the oil molecule; our'previously" described modes of practiceof' the instantinvention increase toxicity by; among other things, raisingthe specific gravity of aromatic andyor' overall fractions by what we believe to be. controlled side chain elimination; at least to a; degree, from the ring nuclei; However, we have discovered that when removing side chains from the ring nuclei which lower water solubility, nascent radicles. are formed which may; on the one hand, further alkylatethe ring nuclei; or, on the other hand, polymerize to form high boiling chain structures which boilwithirr the range of the reformed aro mati-cs. In either instancethis is not desired, and moreespecially the polymerization of the nascent radicles to form relatively high boiling chain structures-isnot desired for the reason that they dilutethe toxicity ofthe reformed aromatics".

We have discovered that if wewill' remove side from the ring nuclei within a; relatively short period andtherrsheck cool the entire bene-- ficiation; a. certain degree of the said polymerization and/or alkylation is precluded, thus resulting in a toxicity in the reformed, modified and /orconver-tedoil comparable tothat of high temperature coal tar oils.

When applying this mode of practice to our instant invention; we hold-the treating period to not in excess of twdhours; and preferably not in excess' -ofabout 30-45 minutes. When employing relatively high temperatures within the extreme upper liinits-ofthe range-previously disclosed, period'sof 15-30-minutes, or less; will sufllce forthe necessary reforming previously taught. Immediately thereafter the beneficiation is shock cooled to s temperature below about 250 0., and preferably-below 200 C; by a relatively cool oil; which may be the preservative oilpreviously madeby the process. The reformed oil is fractioned as shown above.

Example 8i-A petroleum: aromatic, as for-example, the Shell oil previously described, is pumped in closed circuit through an apparatus designed-- to- Withstand high pressure and high temperature; 'I 'hepressure is=maintained at 1000' pounds per square inch at a temperature of 480 C.- Theoil in the closed circuit is kept in circulation. At the end of about one hour or one hour and l5-minutes-, the heat treated oil is continuously withdrawn, with compensating admission of iresh" feed tothe circuit". The withdrawal and admission are so regulated asto provide the heat treating period above named. Upon inspection of the withdrawn heat treated-material the percent age and specific gravity of aromatics in the 210- 35596; cut Willi be found to fall within the limits previously disclosed The overall specific gravi-- ti'es offractional parts of; the 2l0-355 C. out will alsobe -found t0 fall within the limit previously shown; and the-toxicity-of the-- overall 210-355" C. out will compare favorably with high temperature coal tar creosote.

In previous examples, the overall feed stock has been shown as being treated. In lieu of this, the raw feed stock may be divided into two or more fractions and separately treated. As an example, the feed stock may be divided into a relatively low boiling and relatively high boiling fraction. The low boiling fraction is then treated at a relatively high temperature within the range disclosed, and the high boiling fraction is treated at a relatively low temperature within the range disclosed, the periods of treatment in this instance being the same as taught previously for high and low boiling cuts, beneficiated or otherwise. If three cuts of the raw feed are made, the lowest boiling fraction is treated at the highest temperature, the intermediate fraction at an intermediate temperature and the highest boiling fraction at the lowest temperature. This teaching applies to any number of cuts into which the feed may be divided.

Viewed broadly, the product of the instant process is a reformed, modified and/or converted petroleum oil boiling preponderantly between 210- 355 C., with at least about 15-20% material boiling above 315 0., having at least about 70% aromatics in the materials boiling between 210 C. and 355 C., and in the fractional parts of the oil boiling between 2l0-355 C., certain specific gravities as taught in the foregoing.

The pressures in the present invention are in excess of atmospheric (with the possible exception of the second step of the mode of practice described in Example 4) and may be as high as practicable, and these pressures may be autogenous or arranged for by means well known in the art. 7

Either liquid or vapor phase may be practiced and this disclosure is specifically to be read into all examples. Non-inventive skill will enable those acquainted with the art to coordinatetemperatures within the range disclosed with relatively moderate pressures in order to provide vapor phase practice. When employing vapor phase operation and processing any of thefeed stocks previously described, definite periods falling within the limits previously disclosed will provide specific gravities and aromatic percentages shown in the foregoing.

One phase or various phases of one example may be substituted for a phase or various phases of another example where the substitution is obviously workable. g V

It is to be strictly understood that all temperatures, pressures and periods of treatmentshown in the examples are for purposes of illustration only.

Intermittent or continuous operation, or a combination thereof, may be practiced in the instant process, and those skilled in the art can apply this to our invention without recourse to inventive skill.

Any theories or beliefs herein stated are not necessarily controlling; our invention being limited only by the scope of the appended claims,

Minor changes Within the scope of the appended claims may be made without departing from the spirit of the invention.

We claim:

1. In the induction of toxicity to wood destroying fungi into a mixture of petroleum fractions boiling preponderantly above 270 0., characterized by inherent but inhibited toxicity and a substantial percentage of materials of ring structure content, the process which comprises: subjecting said material at superatmospheric pressure to a temperature selected between the limits of about 325-550 C. unveiling toxicity in the material under treatment by carrying on the process for a period not substantially in excess of about two hours, the period being so selected with reference to the chosen temperature and pressure as to jointly provide in the beneficiation newly formed materials boiling below 210 C., a percentage of aromatics in the fractions boiling between 210- 355 C. not substantially less than about and a specific gravity in the aromatics above named falling between the limits shown in the appended tabular data:

Fractions Low Limit High Limit whereby to provide a material of induced toxic properties.

2. i'he process of claim 1 with inclusion of segregating from the beneficiated material an oil of the wood preservative type characterized by induced toxic properties, boiling preponderantly between about 210-355 C. and having at least 15-20% residual materials boiling above 315 C.

3. In the induction of toxicity to wood destroying fungi into a mixture of petroleum fractions boiling preponderantly above 270 0., characterized by inherent but inhibited toxicity and a substantial percentage of materials of ring structure content, the process which comprises: partially unveiling toxicity in the named materials by subjecting same at superatmospheric pressure to a temperature selected between the limits of about 325-550 C. whereby to provide an overall beneficiation having relatively high and low toxicity in the materials boiling below and above 270 C., respectively; segregating all of the materials of relatively low toxicity boiling above 270 C. and subjecting same at superatmospheric pressure to a temperature selected between the limits above named; unveiling toxicity in a relatively high degree in the materials under treatment by carrying on the process in both steps of treatment for periods totalling not in excess of about two hours, the periods being so selected with reference to the chosen temperatures and pressures as to provide newly formed materials boiling below 210 C., a percentage of aromatics in the fractions boiling between 2l0-355 C. not substantially less than 70%, and a specific gravity in the aromatics above named falling between the limits shown in the appended tabular data:

Fractions Low Limit High Limit whereby to provide materials of induced toxic properties; and commingling the segregations above named whereby to provide an overall oil of induced toxic properties which contains fractions essential in an acceptable preservative impregnant.

4. The process of claim 3 with inclusion of segregating from the beneficiated material an oil of the wood preservative type characterized by 13 induced toxic properties, boiling preponderantly between about 210 C. and 355 C. and having at least about 15-20% residual materials boiling above 315 C.

5. In the induction of toxicity to wood destroying fungi into a mixture of petroleum fractions boiling preponderantly above 270 0., characterized by inherent but inhibited toxicity and a substantial percentage of materials of ring structure content, the process which comprises: subjecting said material at a relatively high pressure to a temperature selected between the limits of about 325-550 C. for a period not in excess of about one hour; thereafter subjecting the heat treated material substantially in entirety to a relatively low pressure without a substantial reduction in temperature for a period not in excess of about 30 minutes; unveiling toxicity to a relatively high degree in the material under treatment by carrying on the two-stage process for periods falling within the limits above named, the periods being so selected with reference to the chosen temperature and pressure as to jointly provide newly formed materials boiling below 210 C., a percentage of aromatics in the fractions boiling between 210-355" C. not substantially less than about 70%, and a specific gravity in the aromatics above named falling between the limits shown in the appended tabular data:

whereby to provide a material of induced toxic properties.

6. The process of claim with inclusion of segregating from the beneficiated material an oil of the wood preservative type characterized by induced toxic properties, having at least about 15-20% residual material boiling above 315 C., and boiling preponderantiy between about 210 C. and 355 C.

7. In the induction of toxicity to wood destroying fungi into a mixture of petroleum fractions boiling preponderantly above 270 C., characterized by inherent but inhibited toxicity and a substantial percentage of materials of ring structure content, the process which comprises: subjecting said material at superatmospheric pressure to a relatively low temperature selected between the limits of about 325-550 C. for a period not in excess of about one hour; thereafter subjecting the heat treated material substantially in entirety at superatmospheric pressure to a relatively high temperature for a period not substantially in excess of about one hour; unveiling toxicity to a relatively high degree in the material under treatment by carrying on the two-stage process for periods falling within the limits above named, the periods being so selected with reference to the chosen temperatures and pressures in the two steps as to jointly provide newly formed materials boiling below 210 C., a percentage of aromatics in the fractions boiling between 210-355 C. not substantially less than about 70%, and a specific gravity in the aromatics 14 above named falling between the limits shown in the appended tabular data:

properties.

8. The process of claim 7 with inclusion of segregating from the beneficiated material an oil of the wood preservative type characterized by induced toxic properties, boiling preponderantly between 210 C. and 355 C., and having at least about 15-20% residual materials boiling above 315 C.

9. In the induction of toxicity to wood destroying fungi into a mixture of petroleum fractions boiling preponderantly above 270 0., characterized by inherent but inhibited toxicity and a substantial percentage of materials of ring structure content, the process which comprises: subjecting said material at superatmospheric pressure to a temperature selected between the limits of about 325-550 C.; unveiling toxicity in the material under treatment by carrying on the process for a period not in excess of about one hour, the period being so selected with reference to the chosen temperature and pressure as to jointly provide newly formed materials boiling below 210 C., a percentage of aromatics in the fractions boiling between 210-355 C. not substantially less than about and a specific gravity in the aromatics above named falling between the limits shown in the appended tabular data:

Fractions Low Limit High Limit 210235 C 0. 9419 1. 0430 235270 0-- -1 1. 0061 1. 0006 270-315 U 1. 0360 1. 0933 315-355" C 1. 0913 1. 1285 whereby to provide a material of induced toxic properties; and protecting the induced toxicity by shock quenching the overall beneficiation.

JACQUELIN E. HARVEY, JR. ROBERT H. WHITE, JR. JOSEPH A. VAUGHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS