Paper No. l

DEPARTMENT OF COMMERCE UNITED STATES PATENT OFFICE

EXAMINATION FOR REGISTRATION TO PRACTICE

FEBRUARY 9, 1965

Time: 3 hours

Paper No. l consists of 20 questions. Make your answers brief and to the point. Number each answer and leave at least two lines between answers. Write on only one side of the paper.

1. Application files, both pending and abandoned, are normally kept in confidence. Under what circumstances may persons have access to such files without permission of the inventor or owner?

2. Adams, a patent attorney with many pending applications, has suddenly died. His widow and sole heir has asked Carr, a patent attorney friend of Adams', to look into Adams' files and take necessary action. After inspecting the files, Carr, using his own letterhead which includes the words ''Registered Patent Attorney, 11 his address, and telephone number, writes to all of Adams' clients, informing them of Adams' death and telling each of those with pending applications of the status of the case and when response is due, if any. Carr closes his letters to those with pending cases with the sentence, "You should without delay appoint some registered patent attorney or agent to represent you in your application." .

Comment on the propriety of Carr's letters.

3. Brown's application for patent claiming a paint composition was filed July 7, 1961. The application also dis­closed the details of a spray gun in which the paint could be used. On August 12, 1963, during the pendency of Brown's appli­cation, he calls your attention, as his patent attorney, to a patent issued to Allen on August 24, 1962, on an application filed August 3, 1961, disclosing and claiming a spray gun identical in essential details to Brown's.

If Brown decides he wants patent protection on the gun, what must be done and when?

Paper No. 1 - Page One

4.. (a) In connection with the first amendment received in an application for patent, the examiner determines that amendments to the specification, to the claims, and to the drawings as to the curvature of a cam involve matter not originally disclosed.

What is the applicant's recourse if he disagrees and an issue is reached?

(b) Assume that amendments to the specification and drawings alone were proposed. Would your answer be different than in (a)? If so, why? If not, why not?

5. (a) It is found that a previous amendment made to an application specification is in error and an insertion must be made.

What is the proper procedure?

(b) What is the proper procedure for reinstating subject matter previously cancelled from an application speci­fication?

6. Jones filed an application for patent disdlosing a novel type of fan blade wherein because of the scooped shape of the body of the blade combined with a particular wavy edge of the blade he is able to move twice as much air as conventional blades of the same area and using the same amount of power. During pendency of the application, sales figures demonstrate that the fan blade is not only useful but its appearance is attractive. Jones asks about obtaining design patent protection in addition to utility patent protection.

What would you advise him and why?

7. Watkins, an Australian, tells you, a patent attorney, that some time ago in Australia he invented a novel mechanical pencil which he, for the last four years, has been manufacturing and selling in Sidney, Australia. The device was very successful throughout that period due to word of mouth advertising and to printed circulars which he distributed. He says the device has not been used in the United States, and he wishes to know whether he can obtain a U. s. patent.

How would you advise him and why?

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8. In a first action by the examiner in a patent appli-cation you are prosecuting, consisting only of a restriction requirement, a two-month period is set for response. Your client is in Europe and at the end of seven weeks you have stj_ll not been able to get advice from him as to which invention he wishes to prosecute.

(a) How can you get an extension of three months in which to respond?

(b) The extension is granted and near the end of the additional three months you find that your client is seriously ill and, thus, still unable to answer. You telephone the examiner and ask for an additional three months extension.

What sort of advice may you expect to get?

9. On March 13, 1963, Wells, the president of a small corporation, s0eks your advice and states that one of his employees, an engineer who has since resigned because of a dispute with management, had invented a novel clutch, while still an employee. He further states that the clutch has been marketed since July 1962 but the engineer now refuses to execute an assignment. You prepare an application on the clutch promrtly and the inventor refuses to execute it as well as the assignment.

Does the company have any recourse?

If so what, and what must be filed?

If not, why not?

10. Jones asks you to prepare a patent application for him on a gauge block which differs from the usual polished bloc!~ j_n that it has been immersed in a 40° C acetic acJ_d bath for 5 to 7 minutes. The etching treatment improves the handline characteristics of the block but produces no discernible physJcal change in the block's surface.

Can a proper patent claim be drawn to the block?

If so, how?

If not, why not?

ll. Name three situations in which drawings may properly be transferred from one patent application to another.

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------------

1~. While you are writing your appeal brief in response to a final rejection of Jones' application on a patent to Smith, Jones informs you that evidence just discovered establishes that, although Smith's filing date antedates his by over ten months, he actually conceived of his invention 3 months prior to Smith's filing date.

What action do you sugge~t?

What types of proof and showings should be filed?

13. Wood's application, filed January 7, 1960, is drawn to an aircraft rate of climb indicator. One part of the claimed dev1ce is disclosed merely as a box labeled "amplifier." The examiner has consistently held that this is an inadequate dis­closure and has so rejected the claims. After final rejection a continuation-in-part application is filed on October 3, 1963, disclosing a specific amplifier used in the instrument. The examiner in his first action in the new application rejects the claims on a reference which was filed June 22J 1962 and issued April 10, 1964. Is the rejection proper? If so, why? If not, why not?

14. Baker asks you, a patent attorney in San Francisco, to take over the prosecution of his patent application which he has been prosecuting himself. It is a reasonably simple case, but you notice that the period for response to the initial action on the case expires the next day.

Can abandonment be avoided?

.If so, how?

15. Section 103 of 35 U.SoCo imposes a standard involving obviousness as a bar to the grant of a patent. What is the standard?

16. In a decision on an appeal from the final rejection of claims 12 and 13 in Burke's application, the Board of Appeals recommended the allowance of claim 12 provided it was amended to include the phrase "said frames including opposed transparent members. 11 The Board affirmed the examiner as to claim 13 and remarked that the claim did not include a disclosed "corner fastening means."

(a) If Burke amends claim 12 in the recommended manner what action by the examiner may be expected? Why?

(b) What action may be expected if there is submitted an added claim, identical to amended claim 12 except for omission of the word "opposed 11 ? \vhy?

(c) If claim 13 is amended to include 11 corner fastening means" what action may be expected? Why?

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17. As Johnson's attorney, you have received a decision dated July 2, 1962, by the Board of Appeals affirming the examiner's rejection of all claims in Johnson's patent application. After receiving this news, Johnson comes into your office on August 3, 1962, and shows you the results of recently conducted tests which seem to show that Johnson's device is superior to the devices of the prior art.

Can anything be done to obtain consideration of the new evidence?

If so, what?

If not, vJhy not?

18. Taylor's application for patent on an automatic weighing scale including claims l to 14 is filed in the Patent Office on April 3, 1961. In his initial action, the examiner rejects claims l to 7, drawn to a control system subcombination, on a patent to Black, issued June 8, 1943. He rejects the remaining claims 8 to 14, drawn to the scale combination, on a patent to Winston, issued April 18, 1961, and filed June 27, 1958. The examiner points out in his letter that Winston, in some of his claims, is claiming substantially the invention of claims 8 to 14.

If Taylor feels he is the first inventor of the scale, what should be his action as to each of the claims?

19. The examiner's first action in an application includes statements that the oath is stale and applicant's post office address has been omitted.

How would you correct each of these deficiencies?

20. Barnes prepared and filed for Gardiner. a patent application. Three months after filing and prior to the first office action, Barnes decided that more than one invention was disclosed and, to expedite matters, filed three divisional applications drawn to some of the subject matter disclosed and claimed in the original application, simultaneously cancelling all claims in the original application drawn to the subject matter being claimed in the divisional applications. In his first action on one of the divisional cases, the examiner rejected the claims therein on the ground of double patenting, referring to the parent case.

Is the examiner barred from making such a rejection?

If so, why?

If not, why not?

Paper No. 1 - Page Five

Paper No. 2

DEPARTMENT OF COMMERCE UNITED STATES PATENT OFFICE

EXAMINATION FOR REGISTRATION TO PRACTICE

FEBRUARY 9, 1965

Time: 3 hours

This paper is in two parts and requires the drafting of three claims in each of the two parts.

Answer Part No. 1 and either Part No. 2A or Part No. 2B.

PART NO. 1

APPARATUS CLAIMS

Draft three claims of substantially varying scope cover­ing the "Electric Pencil Sharpener" shown in the attached sheet of drawings. Assume that the prior art shows electrically driven pencil sharpeners having cutters which have a planetary motion. Figure 2 in the drawings is a perspective view of the cutter carrier. Members 44 and 45 carry the contacts for a work operated switch.

Designate the 11 broadest, '' the 11 intermediate, 11 and the "narrowe·st 11 claim. Claims in dependent form may be used. The claims should not distinguish from each other by merely immaterial limitations.

Paper No. 2 - Part No. 1 - Page One

.:~:LECTHIC PENCIL SHAHPl~NEH

42

5

FIG. 1

Fl G. 2

21

21 FIG.3

Paper No. 2 - Part No. l - PaEe Two

/

Dro.ft th1,cc process claims of cubr.;tantJally vary:Lnc sco[ .. ~c covc:r·~i.n[; olthcr tl1c (A) 11 Mcthod of rrreat1ng f.1

1J.Sh, 1' or

the (J3) 11 I-Ictl1od of Convcrt:inc; NaphtharJ to M:i.ddlc D:l.sti1lates 11

descr>J-ocd ::.n the follov·;.:.n[j dr>awJnss and descr~:t.ptJ.on. ClaJms ln ·'.cpencTcnt form may /.)C twe(.

--·---............. ·---·------~~-----·-------·-------- -··-·------·---._---·-·----·

l::A.li.rr l·TO. ~A -------

'fhis inventi.on relates to a method of treat ing fish such as sardines a.nd the like an...t especially to a method whereby the flavor and taste msy be improved, the fish shrunk, the skin set.} a portion of the water extracted and as mach of the oil removed as possible without excessive handling and mutilation prior to placing the fish in the cans and sealing and finally cooking and sterilizing the same. ·

In cannel'ies where sard~nes are packed it has been found that considerable shrink­age takes place when the sardines are cooked, and further that it is desirable to remove a portion of the oil content of the fish and to preserve the naturally sweet flavor of the sardines. ·.

It is, accordingly, customary to shrink the sardines, cook the flesh and remove a portion of the oil prior to cooling and placmg the sardines in the cans q,nd sealing ( afte~ which the final cooking of the· b<me and sterilizing is don~) as flavor and appe~rance would o.therw1se be detrimentally affected. For instance, if sardines were placed in cans without :Rre-shrinkage and extraction of oil, they would shrink to such a degree during the cooking operation that sufficient space would be pnoduced to permit free movement of the fish within the cans. Such movement during shipping and handling would cause the fish to become marred and broken and as considerable oil would also be liberated in the can during the cookin$' operation, the fJ.ppearance would be unsatisfactory when the can was opened by the consumer and the product would not be as salable.

The mos.t common II)ethod employed by canners to msure pre-l)hrinkage and removal of oil is, briefly statedt as follows~

A..fter the fish has been prepared as by scalmg, removal of heads, entrails, etc. and washed, they are first placed on endless con­veyors ~nd passed through a drier to dry off the was~ water and a portion of the water ('ontent m the fiAh, thereby drying the skin. Secondly, they are loaded mto comparatively large Wlre baskets and then dipped in hot oil . or. hot . brine for the purpose· of pre­shr•.nking the. fish and for toughening or set~mg the s~n, and for .c~king the JDeat. Th 1 rd, the baskets contR.mmg the· fish are then partially drained and sometimes sub-­jected to a steaming operation after which they are plaood in a room to drain and cool. Fourth, after cooling, the baskets are emp· tied upon the packing tables and the fish thus delivered to the packers who pack them on.e ~y one in the cans. Fifth, the cans con~ tammg the fish are in some instances sauced and passed through an exhaust box and t~e lids are then a.pplied and double seamed. 81x~h, the cans oontainin~ thrJ fish are then subJecf:ed to a final cookmg and sterilizing operatwn when they are ready for labeling and shipment to the market.

The object'ions to this method are several. In the first step described where the fish are

·placed on conveyors and passed through driers, the fish are tumbled and dropped from. one conveyor to another as several superposed conveyors are employed. This tumbling and dropping pf the fish tends to

Paper No. 2 - Part No. 2A - Pa~e One

bruise and break the fish and the skin. When the fish are soft5 it is almost impos­s.ible to dry them Eroperly. Temperature control of drier is a~so difficult. In the secq onrl step where the fish are loaded into the baskets and submerged in hot, oil, it must be considered that the fish are again handled with chances of further breakage. The· baskets are fairly large and the fish are placed in contact and on top of each other in sevet·al layers. This is objectionab.le as they have a tendency to adhere to each other and to the basket when cooled, due in part to the coating of oil which is left on the fish a:fter submersion in the hot, oil and to the gl~e for:rn~.d by the skins. The oil coating oXl.<iizes to some extent in a manner similar to a V9.rni~h :1.nd hec:omes sticky? and some g.lu11;1 is fo~med. by the skins; hence, when the fish are. dumped out on the packing tables~ the .fish which adhere to each other and to the h~ .. ikets musf.. be separated with t.he re~ sult. that piece~ or skin are pulled off or the fish is broken, A loss of 10% or more of the fish by hx~nkage and mutilation at this point is quite comJn<m. .Another and serious ob­jection is th:e~ cookjng of the fish in oil. Some p&ekern employ a bath of ootton~seed oil or the like in wh~eh to cook the fish, but it is obvious that this may ooon become mixed or substantially replaced by fish oil due to the oil rendared or driven out of each individual fish n.-~ it pM.~s under the oil bath and t.o th() ~H.rrrying out the original oil by the fish. Most however~ use cott..on~seed oi.t Thi comparatively little difference as either cotton~seed oil or fish on. soon beoomM t.hi~k, _partially rancid and d~;-r;om~ du~ to oxidation flnd eva.p" oration at ~h€:l temperature m~dnta.ined. JUoreov<er, due to the continuous addition of particles of: skin and broken portions of fish~ scales and sardine entrails which are carried over to the oil tank and set.tle to the bottom, the oil becomes polluted and the acidity t~?nds to become excessive, In other words, the ('Ooking of the fish in the oil bat.h for the purpose of shrinking it and cooking the · me9.t does not add to the delectable flavor de­sia·ecl? but. cnnvcrR(Ily, rletracts from t.he nat­mrrtlly Rweet sardine flu.vor; and further­more? the cooked fish picks up the flavor of the fry oil. The flavor of the brine-cooked fish is superior to that of the oil cooked fish, bu~ the appearance of the finish product when canned .is such as to render the fish unsightly, and not salable as the best pack.

Another objeetionable feature is enccnn­tered in the third step where; the fish are subjected to a cooling operation, i: e., after the fish have been cooked in the hot oil or hot brine nncl then drained and steamed, the baskets containing the fish are placed in a lar~e room where they are permitted to re~ mam anywhere from ten to forty-eight hours) the object being that of allowing a further smrill amount of shrinkage, drain­ing oft' of oil and thoroughly cooling the fish before delivery to the packers who place them in the cs,ns. This long period of stand~ ing is decidedly undesirable ns it permits contamination, the cooked fleRh is in contact with the uncooked bone which aids bacterial growth causing some putrification; more­over, the flesh tends to darken markedly when standing. The oil coating on the fish tends to become more or less rancid, thereby impartin~ a rancid taste to the fish.

The obJect. of the present, invention is to generally improve imd simplify methods of the character described and especially to provide a method of improving the appear~ ance of the fish, color of the flesh and flavor, of pre.:.shrinking the fish and removing as much of the oil as possible, to accomplish these operations in a minimum of time with mbstantially no disturbance or handling of the fish, to prevent contamination and putrig fication, and to prevent splittin~ or breaking the fish or the skin, moreover avoiding a long cooling period.

For the purpose of describing the method formine: t.he subject matter of the present application~ reference will be made to the accompanying drawing which is a diagram­matic view of one form of apparat.us which may be employed.

iteferring to the drawing, A. indica~ a main frame at the. opposite ends of which are journalled Bbafts 2 and 3 ~nyirllg pul~ ley~ 4 o.nd 5, · Supported b;y the· pulleys is an endless conveyor 6 whieh ia preferably coD.Dtrncted of a foram.inoua material, such ·~ wi"llll netting ox: the like.. Power may be transmitted to drive the endless conveyor in the direction of arrow a, for instance through means of a driving pulley 6 and a belt 7. Disposed adjacent to one end of the belt where the fish to be treated are de­livered, is a downwardly directed pipe 8 on the ]ower end of which is mounted a dis­tributor head 9. This piP.(> is connected with nn nir blower or the hke and a heater and. warm air are continuously projectecl

Paper No. 2 - Part No. 2A - Page Two

downwardly against the surface of the con­veyor and the fish supported thereby. Ar­ranged adjacent the opposite end of the con­·veyor is a cooler of the refrigerating type which is generally indicated at 10. The cooler consists of n housing, interior of which is mounted n series of coils 11 through which a refrigerating medium is circulated in any suitable manner. Any other suitable cooling apparatus may, how­ever, be employed. Disposed intermediate the cooler 10 and the hot air deliveri.ng pipe 9 is a housing generally indi~uted at 12, and mounted interior thereo-f is a plurality of electric hea.ting elements 13. The housing may be divided into three or more com­partments as shown and the . heating ele­ments may be ·heated to varymg tempera­t.ures SO t!lS t.o gra.dually heat the fish llS the conveyor pass'tls underneath, the heating of the fish being accomplished by the radiant heat. energy 1;rojected by t,he radiant heating elemmtAt,s.

In 9-dual the fish to he· canned !1re usually passed through a scal~r after which the hea.ds and entrails are removed and t,he fish are washed, This part of the

is not disclosed in too diagram­matic drawing as standard methods or machinery nre employed therefor and used in most canneries. After the fish l\ re cleaned they !are delivered to a foraminated con­veyor indicated at 6, The fish are spread out over t,he foraminated conveyor so as not t.o contact with ea<!h other and as they pass under the head 9 they are subjected to a blast of warm d.rv air. The air dries oft' the water and it al:So partially dries the fish.z thereby tending to shrink the fish and haro.en the skin. During the continued movement of the conveyor 6, the fish yass under the heater 12 where the fish wil be subjootA!!d to the radiant heat of the elements 13. The fulh are gradue,lly brought up to a desired temperature and the~ are broiled a.nd are at the same time suffimently heated to render or drive out oil. the primary ob­ject being .th$t .of cookiug the mea~, setting the skin, remoVIng as much of the 011 as pos~ sible, properly slirinking the fish, and im­P"'oving the flavor and &{>pearanoe prepara­tory to cool.inR' and placmg the fish in the cans for the linal oooking and sterilizing operation. .Alter the fish have been broiled, they pa.oo through the cooler 10 and are here rapidly cooled. The conveyor may be ex­tended to the point where the packers are stationed and the fish-in their separated con­dition may be picked di:rootly from the belt t1nd placed in t~e cans, and the cans are then .·

passed through an exhaust box and the lir1 ·

are then applied. The cans ra~e then seale~ and subjected to the final cookmg and steri­lizing operation.

The present application merely relates to the method of heating the fish to improve flavor. the pre shrinking the fish and to re· move, oil and some water. The steps of scalincr, cleaning, etc., and of placing the fish i~ the cnns and of sealing and final cooking and sterilizing the same form no part of the present application as customary prRctice may the.re be resorted to. Suffice 1t to say, that it is Jesirable to pre-shrink the fish, broil the mea.t, imparting thereby a delectable flavor to the meat, remove the oil, and handle the fish as little as possible a'"! handling of the fish or contact of the ·fish with each other tends to bruise or bres.k the fish and the skin. In the present instance, pre-shrinking and broilipg takes place with· out any ha.ndling whatsoever as the fish art3 not touched from the time they are delivered to the conveyor 6 until they are picked off by the packers. The preliminary drying operation such as subjecting the fish to a blRst of hot air or otherwise may or IVlay not be employed as one or more units may be added to the radiant energy heater indicated o.t 12. Such units could be operated at lower temperatures and as such would serve the Rame function, to-witl that of drying off the 'vash water and part1ally drying and hard­C?.ning the skin, It might also be st.Rted that the fish are brought up to temperature. by the radiant energy so that danger of bursting or split~ing the skin of the ~h. is. subs~an­tially ehmmated. However, 1f 1t .Is d~mred to increase the speed of the ceperatwn, 1t has been found that the oil may be liberated more rapidly by subjecting the fish to one or more perforating operations before they are subject~d to the :radiant (mer~. Such perforation may be a.c?omplished 1.n numer~ ous ways and illustratu;m thereof 1s ~ccorda ingJy tbought unnecessary. .

Wbile certain features of the present m.­vention are more or less specifically described and illustrated, I wish it understood . th~t vaTim.JA changes may be resorted to w1thm the scope of the sp~nded clahns; similarlyi thRt the ma~rials and finish of the seven parts employed may be such as the manufac= turer may dictate or varying conditions or usee may demand, .

Paper No. 2 - Part No. 2A - Page Three

Paper No. 2 - Part No. 2A - Page Four

PAl\T NO. 2B

f/U~TI-IOD 011' CONVEHTING lJAPli'I1riAS TO MIDDLE DISTILLATSS

The present invention relates to distillate fuel manu­facture and it pertains more specifically to the manufac­ture of high quality distillate fuels such as heating oils, diesel fuel, jet fuels and the like from naphthas boiling in the gasoline boiling range.

The principal object of the present invention is to provide a process for converting. low octane and/or un­stable naphthas into materials of higher value and higher boiling range.

Hitherto, oil refineries have been generally operated to maximize naphtha production for use as gasoline motor fuel. Some naphthas are of substantially lower octane value th<m others, but could be blended with high anti-knock constituents to produce gasoline blends of acceptable gua!ity. However, with the introduction of high compression ratio automobile engines, the octane

·requirements of gasoline have been steadily increasing, thus severely narrowing the choice of constituents suit­nble as gasoline blending agents. Thus, much virgin naphtha and naphthas resulting from catalytic cracking of gas oil, hitherto used as gasoline blends for engines of moderate compression ratio, can no longer be used for this purpose. Similarly, refinery processes such as fluidized coking of residua, and visbreaking operations produce naphthas that are unstable and sludge forming, and are of too high sulfur content for satisfactory use as fuels.

Concomitant with the increasing accumulation of these relatively low value naphthas in the refineries, there has grown up in recent years substantial demands for hy­drocarbons boiling in the middle distillate range of about 300° to 750° F. The rapid growth of beating oil installa­tions both here and abroad, and the rapid dieselization of transportation equipment has caused the supply of middle distillates to be out of balance with that of motor gasolines. However, operating crude oil and distillate refinery processes' to maximize middle distillates would seriously interfere with the production of high quality nnphthas. An object of the present invention is to pro­vide middle distillate fuels without interfering with maxi­mum high quality and octane gasoline production.

Thus, heretofore middle distillate fuels have been pro­duced as by-products in the manufacture of gasoline, and such fuels of relatively high quality could be obtained directly from fractions of the virgin crude oil ~r from the cracking of virgin crudes. The phenomenal mcrease in demand for middle distillate fuels bas presented a serious problem to the oil refining industry.

Middle distillates, or distillate fuels, generally boil in the range of about 350° to 750° F., the so-called beater oils boiling in the range of 350° to 5SOo F., while diesel fuels boil at about 400° to 650° F.

In accordance with the present invention, refinery im~ bnlnnce between gasoline and heating oil demands and stocks are restored by catalytic conversion of low quality naphtha fractions into middle distillates. In a sense t}Us is the reverse of the hitherto trend of petroleum refinmg where the gasoline fraction was the desired product, and where low grade gasoline fractions were upgraded to high anti-knock material by such processes as reforming or isomerization.

The present invention involves principally conversion

of naphtha into middle distillate by catalytic treatment with liquid hydrogen fluoride and in the further presence, if desired, of certain promoters such as boron fluoride or other halide, iron fluoride, and similar compositions. In one embodiment of the present invention, light virgin naphtha is directly converted. In another embodiment, naphtha may be thermally, catalytically or steam cracked to a relatively low degree of conversion, forming sub­stantial quantities of olefins which are then passed to the catalytic conversion zone. In still another embodi­ment, low grade catalytic or coker naphtha is fed di­rectly into the conversion zone, or is mixed with virgin or casinghead naphtha prior to conversion.

The catalyst employed in the present invention is an­hydrous liquid HF. This may, particularly when virgin naphthas are being reacted, be augmented with BF3 • In this case from 0 to 60 mol percent, preferably, 25 to 40 mol percent BF3 based on HF, may be employed. Lesser amounts of from 0 to 10 mol percent, but pref­erably, 0 to 2 mol percent BF3 may be employed in processing the more reactive catalytic and coker naphthas or other naphthas containing olefins.

Several critical conditions must be maintained in ac­cordance with the present invention to obtain good yields of middle distillates. Temperatures must be in the range such that middle distillates rather than lubricating oil range material on the one hand, or products boiling lower than middle distillates on the other, are formed. In gen­eral, temperatures should be in the range of from about oo to 350° F., preferably, 32° to 250° F. Process temperature is determined by the nature of the feed, the catalyst composition and the catalyst concentration. Normally, temperatures in the range of 160° to 250° F., preferably, 175 o to 225 o F. are employed in process­ing virgin naphthas using HF-BF3 catalyst, while lower temperatures in the range of 25° to 150° F., preferably, 7 5o to 125 o F. give satisfactory results in processing catalytic or coker naphthas or other unsaturated feeds. Pressures are such that at least a portion of the catalyst and the feed are maintained in the liquid phase. Catalyst to oil ratios are in the range of 0.1 to 5/1, and pref­erably 0.5 to 2.5/1, and contact times to 5 to 180 minutes are maintained. Again, these conditions will be deter­mined by the reactivity of the naphtha feed, high catalyst to oil ratios and long contact times being required with virgin naphthas with low catalyst to oil ratios and short contact times being satisfactory for the conversion of catalytic or coker naphthas. Specifically, catalyst to oil ratios of 1 to 5!1, preferably 2 to 4/1, and contact times of 30 to 180 minutes, generally 30 to 120 minutes, are employed in processing virgin naphthas. For catalytic and coker naphthas, catalyst to oil ratios of 0.1 to I. 5/1 and contact times of 5 to 30 minutes are normally !!atis­factory.

An important problem arising out of the reaction and reaction conditions heretofore described is the formation of secondary reaction products, and in particular the formation of dry gases, principally propane and isobutanc, decreasing the ultimate yield of desired product. It has been found that the yield of destred middle distillates can lJe increased by passing these. light products_ back to

Paper No. 2 Part No. 2B - Page One

th~ reaction zone where ~ither through mass action effects or through their reaction with the catalyst system present, they are converted into middle. distillate. Suprisingly, however, it has been found that if a portion of the de~ sired middle distillate product itself is recycled, on the order of 2 to 40% based on feed, the formation of the light material is greatly reduced.

The objects of the invention and its advantages will be more readily apparent from the more detailed descrip­tion hereinafter when read in conjunction with the ac~ companying drawing showing a preferre.d embodiment thereof.

Turning now to the figure, a naphtha feed comprising low octane quality constituents, such as virgin naphtha, is admitted through inlet 10) pump 12 and valve 14 into mixer :lt6. Prefer:1bly, prior to admission to 16, the hya drO\~arbon stream is afhnix.;;d with concentrated, and pref­erably <mhydrous liqwd HF :admitted through line 18 and 'lal.v~; l~t. 'T'b;. ~:.ropor~ion of hydroftuoric acid is prefer­abiy in 0Jr-:J rang~;~ of 2 to 4 times by weight of the total hydrocMbon fluids. Mixing of the acid and hydrocarbons may be etTected by any one of a number of methods, as by use of special mixers or emulsifiers or by maintaining high iintar vdodties m the tines.

Preferably, prior io Rddition of the acid to the hydro­carbon, boron fluoride: is added to the former to the extent or 25 to 40 mol percent ln general, if the hydrocarbon feed i::. mo"ierately or highty olefinic., BF3 may be omitted, whereA.s it~ presence is beneficial and indeed essential when lhe hydro~arbon feed is k)w in ot~fm content, as is the case in virgin naphtha.

The resulting mixture of acid, BF3 and hydrocarbon is passed to beater 22 wherein it is heated to suitable reac­tion temperatures of tbe order of 175° to 225° F., and passed to reaction chamber 24, wherein it is maintained for a period of 30 to l20 minutes at a pressure sufficient to maintajn majo'l portions of the catalyst and feed in the liquid phase. Agitation by any lr •. nown means may be supplied, as by recirculation.

Effluent mixture from reactor 24 is pussed through con~ duit 16 to separator 30 wherein it is separated into two Hquid phases as by cooling and gravitation or centrifugal means. The heavier or HF-BF3 acid phase may be re~ cycled via conduit 32 to pump 34; a portion may con" tinuous)y be passed to an acid fraction a tor (not shown) or other means for purifying and restoring the acid, all in a manner known per se.

Returning to t,be upper layer, the hydrrn;arbon phase is passed through line 36 to fractionator 38, preferably with pressure release. In accordance with the present in·· vention, the light products, such as the butanes and pro­pane, are recycled to reactor 24 via line 40, Similarly, from 2 to 60% by weight of the desired middle distillate, and which fraction boils between about 250° and 650" F., is recycled via line 42 to reactor 24, while unreacted hydrocarbon naphtha may similarly be recycled via line 44. The middle distillate fraction is passed via line 46 to a finishing plant or for further treAtment not forming a part of this invention.

The process of the present invention is further illustrated by the following specific examples.

Example I

A virgin naphtha obtained from a South Louisiana crude and boiling from 215° to 350° F. was treated ac­cording to the method outline above. Experimental con­ditions were: HF/oil wt. ratio______________________________ 2 BF

3/oil wt. ratio _____________________________ 0.4

Temperature, oF-----·------------------------- 225 Contact time, hrs_____________________________ 2

The reactor was a Monel autoclave equipped with an efficient agitator. The developed pressure was held through the treat. At these conditions the naphtha con­version was 71.6 wt. percent and the wt. percent yields, based on naphtha converted were:

c3- ---------------------------------------- 5.6 c4 --~-------------------------------------- 39.5 c5 --------------------------- ____ __ _______ _ 15.4 350°/650° F--------------------------------- 39.5

Example 11

A light catalytic naphtha obtained by cracking a South Louisiana crude and boiling from 165° to 350° F. was treated in a stirred Monel autoclave under the follow­ing conditions: HF/oil wt. ratio______________________________ 0.2 Temperature, oF----------------------------- 150 Contact time, hrs _____________________________ 0.5

No BFa was used. At these conditions 55.3 wt. percent conversion of the naphtha was obtained. The wt. percent yields based on converted naphtha were:

c3- ---------------------------------------- 0.2 c~~, ------------- ____ _____ _______________ ____ o.9 350°/650° p _________________________________ 98.9

Example Ill

The following experimental results were obtained in a statistically planned study on the conversion of naphtha to middle distillate. The experiments were carried out in a Monel autoclave equipped with an efficient agitator. A synthetic blend consisting of 45 wt. percent n-heptane-45 wt. percent n-hexane-10 wt. percent benzene was used to represent a light virgin naphtha feed. Recycle was simulated by charging the respective product fraction with feed. [225° F., 2 HF/hy<lrocarbon wt. ratio, 20 wt. percent BF3 on IIF, 2 hr.

reaction time)

fi!l ~\I I~

3'J

50 5U

It is evident from the above data that middle distillate production is maximized an~ gas make minimized by re­cycling at least a portion of the butane or C4- and 250° F.+ product fra£tions with unconverted feed.

Paper~ No. 2 Part No. 2B - Page Two

Paper No. 2 - Part No. 2B - Page Three