US2349720A - Production of articles of commerce - Google Patents

Description

May 23, 1944. .1. E. HARVEY, JR 2,349,720

PRODUCTION OF AN ARTICLE OF COMMERCE Filed Feb. 26, 1942 l/M Till/WWII!!! can; me

OVER/ 540 /96" 17004 W 0/364190 Eff/0w lame/lino rob/amen Miter- 14.? 4 omroeamnno/v PPODUCT Patented May 23, 1944 UNITED STATES PATENT OFFICE.

7 2,349,720 PRODUCTION OF ARTICLES OF COMMERCE Jacquelin E. Harvey, Jr., Washington, D. 0.

Application February 26, 1942, Serial No. 432,496

5 Claims.

inert gas, in step-wise manner, whereby to provide valuable liquids, as for instance materials useful as solvents, plasticizers and/or wood preservatives.

A further object of the instant process is the production of materials, the characteristics of which are dependent upon, among other things, process variables in the final operating step.

Other'objects of the instant process will be apparent from the following disclosure.

Suitable starting materials of the process of the present invention include tars and fractions "thereof derived from the high temperature of carbonization of coal, as for instance high temperature coke oven tar and gas house tar.

Especially suitable as starting material is the refined pitch secured from high temperature coke oven tar or gas house tar. A refined pitch may conveniently be secured by stripping high temperature coal tar to produce a residuum of pitch, semi-coke or coke, and fractionating the overhead material to recover a liquid useful'as a wood preservative and a higher boiling fraction boiling predominantly above 355 C., said fraction last named being the refined pitch in question.

Among other things, the instant process may be viewed broadly as providing a process for the production of materials useful as solvents, plasticizers and/or wood preservatives by subjecting at least a portion of the starting material, in step-wise manner, to the controlled action of'hydrogen and an inert gas.

The following examples will serveto illustrate the general principles upon which the practice of the present inventionis based, as well as the process of the present invention.

Example 1. -A crude high temperature coal tar boiling substantially 3% at 210 C. is passed through a high pressure reaction chamber at 425 C. and 225 atmospheres pressure whilst contacting a fiow of hydrogen or hydrogencontainmg gas in the .orderof 18,000 cubic feet per barrel material treated. The time of contact is about the present process.

four hours and the catalyst is selected from the group consisting of oxides and sulfides of tungsten including tungstates. The thus beneficiated material will be found to have lowered boiling points, specific gravity and viscosity. It will be found that newly induced materials boiling below 200 C. have been formed. An inspection, periodic if necessary, of the beneficiated material will disclose that fractional increment, depolymerization and/or hydrogen absorption were linear functions of the time element. The beneficiated material is stripped to 315 C. to provide the vaporous low boiling stripped fractions as the intermediate starting material of the instant process. The vaporous stripped low boilers are heated to 400 C. and thereafter are commingled with an inert gas which had previously been heated to 700 C. The proportion of heated inert gas is so selected as to provide in the commingled material an equalization temperature of about 530 C. The time of contact of the commingled ma-' terials is so selected as 'to provide dehydrogenating conditions on the stripped low boiling materials above mentioned. However, instead of super-heating the vaporous intermediate starting material, the evolved vapors maybe directly contacted with the preheated inert gas.

With some intermediate starting materials produced in accordance with the instant process, periods of a fractional part of a minute will be found to provide the desired dehydrogenating conditions; however, longer periods-may be used, as for instance one or more minutes. Int-he instance of using the longer periods of time, with or without a more elevated temperature, plasticizin'g properties of usable quality will be found to have been induced.

The point at which the hydrogen benefici'ated material is stripped is determined by the need at hand.

mingledmaterials has been effected at the named or desired temperature, the materials are passed to suitable condensing and if desired fractionating apparatus to provide a condensed material which is "the finally dehydrogenated material 'of The condensed overall dehydrogenated material, or fractional-parts thereof, will be found to have solvency, plasticity and/or toxicity in excess of ;its intermediate starting material.

A convenient test for solvency may be had by evaluation of the well known Kauri-butanol number or aniline points. A convenient test for plasticity is disclosed at page 96, et seq. The Technology of Solvents, Dr. Otto Jordon, Chemical Publishing Co. of New York, Inc. Toxicity may be evaluated in accordance with Method of conducting the tests, page 2, Tech. Bull, No. 346, U. S. Dept. Agr., 1933.

In the first step of the process wherein the tar is subjected to the action of hydrogen at superatmospheric pressure, the stripped material flowing from the beneficiation and which provides the intermediate starting material of the instant process may conveniently be secured by distillation, release of gas pressure and/or stripping action of gas. After the stripping action, the

stripped low boiling materials may be condensed or fractionally condensed and only a part thereof subjected to the subsequent action of the inert gas; or, the stripped low boiling materials with-.

out condensation may be subjected to the dehydrogenating action of the'inert gas.

If desired water in vaporous form may be supplied in conjunction with the inert gas. As in- ,ert gases employable in the instant process may be mentioned carbon monoxide, carbon dioxide,

hydrocarbon gases inert under process conditions, nitrogen or the like. Any of the gases named in combination with vaporous water may .also be employed. The initial heat of the inert gases named and/or steam may be secured from any convenient source, as for instance by passing through heated tubes, or the inert gases may consist of inert combustion gases, such as flue gases heated to the desired temperature.

Because of the wide variation in possible intermediate starting materials, as aforementioned,

no arbitrarystatement is possible concerning the necessary percentage of inert gases and/or steam, nor is it necessary. A few trials with any of the intermediate starting materials will definitely show the percentage necessary. Using some intermediate starting materials, 75% inert gas and/or steam will prove satisfactory for certain dehydrogenating conditions. However, as will now become obvious, the percentage of inert gas will be dependent on, among other things its character and temperature, time of contact and so forth. 4

5 One of the preferred starting materials of the foregoing. The refined pitch in question has a critical and unexpected treatment period in the hydrogen treating step. This critical period of treatment is in the order of about three hours,

and which if exceeded produces adverse and undesirable reactions, as for instance loss of newly induced fractions, polymerization and/or lowered hydrogen absorption.

When subjecting the crude high temperature I coal tar of Example 1 or stripped high temperature coal tar to the action of hydrogen for the production of newly induced fractions. and/or depolymerization of the molecular complexes it has been found that the percentage of said newly induced fractions and/or depolymerization are linear functions of the time element for periods period of treatmentin the first step (of hydro- 5 instant process is a refined pitch describedin the gen action) is so selected as to provide, fractional ucts, fractional ntars mentioned, fractional increment, depolymerization and/or hydrogen absorption were linear functions of the time element.

Thus the state of the art is that when subjecting crude high temperature tar, characterized by all the filth, insolubles and coke residue common to such material, to the action of hydrogen for production of newly induced prodincrement, depolymerization and/or reduction of insolubles is a linear function of the time element within the periods disclosed.

It is an accepted principle in the art that a distillate of a crude hydrocarbon is more amenable to the action of hydrogen than its crude parent material and consequently should have a longer permissible period of treatment by or with hydrogen wherein fractional increment, depolymerization and/or hydrogen absorption are linear functions of the time element. Applicant has discovered a distillate of high temperature coal tar or the like that does not conform to the accepted teaching above named in that there exists a relatively short and critical period of treatment by or with hydrogen and which if exceeded causes reverse and undesired reactions, that is to say, causes loss of fractional increment, polymerization and/or lowered hydrogen absorption if the relatively short and unexpected critical time period is exceeded. The distillate in question is the refined pitch of the instant process and has a critical time of treatment by or with hydrogen in the order of about three hours.

This critical period of hydrogen treatment for applicants refined pitch was totally unexpected in that this material is a distillate and consequently had been relieved of a major portion of the inherent filth, insolubles, and/or coke residue of the parent stock.

Example 2.-In accordance with the instant process a refined pitch boiling substantially 20% at- 355 C. is charged to a high pressure vessel and hydrogen pumped in to an upper limit of .1800 pounds per square inch. Thereafter the material is treated for two hours and forty-five minutes at a temperature of 425 C., the meanwhile maintaining the contents of the vessel in an agitated condition. At the end of the named period the vessel and its contents are cooled. The beneficiated refined pitch is then distilled to an upper limit of 325 C. The evolved vapors are then contacted with one part of methane and two parts of steam and passed through heating coils wherein a temperature of 465 C. is attained for the commingled materials. Thereafter the commingled materials are contacted with an inert carbon-containing or hydrocarbon gas or gases previously heated to about 710 C The quantity or percentage of the added heated inert gas or gases last named is so selected as to provide an equalization temperature of about 510 C. The time of contact of the finally commingled materials heated to the named temperature is maintained for a period sufficient to dehydrogenate, at least to a degree, the vaporous intermediate starting material. The treated material is condensed and will be found to have solvency, plasticity and/or toxicity in excess of the intermediate parent material. If desired, superatmospheric pressure may be maintained in that part of the process characterized by contacting' the stripped low boilers from the hydrogen beneficiating step with the preheated inert gas. Superatmospheric pressure may be maintained in any part of the flow of the process. As an example, the inert preheated gas or gases may be supplied under pressure.

The condensed inaterial'fnay be fractionated to provide substances useful as solvents, plasticizers and/or wood preservatives. When using certain intermediate starting materials and when the temperature in the final process step is held around or above 500 0., certain fractions of the condensed material will be especially suitable as plasticizers, binders or the like, and more especially this condition obtains if the intermediate starting material represents a deep cut on the first beneficiated material.

The overall finally beneficiated material may be fractionated to provide solvents and plasticize'rs of any boiling range, -as for instance substitutes for the conventionally manufactured materials as noted in the following tabular data:

I T011101 -1 100-150 Iii-Flash naphtha 150-200 Heavy naphtha 150-290 Plasticizersnm 160-360 In the event a solvent or the like is recovered to an upper limit of 270 C., the residual portion may serve as a Wood preserving impregnant by virtue of its increased toxic value, as it will be found that the process controls of the final step of the process induces, among other things, toxicity.

Thus it will be seen that the instant process provides for (1) depolymerizing high temperature coal tar fractions in the presence of hydrogen whilst controlling the period of treatment to provide fractional increment, depolymerization and/or hydrogen absorption as the linear function of the time element, (2) stripping low boiling materials from the beneficiated tar, and (3) thereafter contacting at least a portion of the stripped low boiling materials with that percentage of previously heated inert gas or gases adapted to provide an equalization temperature and other conditions conducive to and effecting dehydrogenation, at least to a degree, of the intermediate starting material.

In the first step of the instant process characterized by the action of hydrogen, pressures from slightly above atmospheric may be employed, as for instance when employing a tungsten oxide or sulfide or catalysts similarly effective. However, higher pressures may be employed, as for example 20, 50, 100 or 200 atmospheres or higher when using less eifective catalysts.

In the step characterized by the action of hydrogen temperatures of between 300 C. and 550 C. serve to illustrate the present process; however, temperatures under pressure conditions that cause no inordinate coking are preferred, as for example 3'75-435 C. or somewhat higher.

Example 3.-An especially attractive form of practicing the instant process resides in contacting a mixture of crude high temperature coal tar fractionsyas for: example a'mixture boiling 200- 345 C.,with a flow 'of hydrogen'at a'pressureof 1-50 atmospheres and ate temperature chosen between the limits of 300-550 C.,-as for instance between-400500 0., say 425 C. The catalyst is selected from a group consisting of oxides and sulfides of tungsten including tungstatesl- -The time of contact is four hours and hydrogen flow about-16,000 cubic feet per barrel feed stock. The beneficiated material characterized by. lowered specific gravity. coke residue and viscosity is stripped to an upper limit ofJsay 290 C; and subjected ,to the second step of the process, as'for example as set forth in Examples 1 and/or-2.

Example 4.-A refined pitch is subjected to the action of a fiow of hydrogen for a period of about two hours and forty-five minutes. .The catalyst is selected from a group consisting of oxides and sulfides of tungsten including tungstates. The

temperature is selected between therange of 375-550 C., as for instance between 400-500" C., say 435 C. The total pressure inthe operation is maintained at about atmospheres or lower as for instance at about 20 atmospheres or lower. At the end of the named period the material under treatment is stripped by gas movement to an upper limit of about325 C., or the stripping may be performed at a higher or lower point. Thereafter the stripped low boiling material is treated in thepresence of a preheated inert gas in a manner similar to operations disclosed-in Examples 1 and/or 2. I I

In the first process step characterized by the action of hydrogen, reaction conditions may be secured by intermittent operation, as for instance in a bomb or the like. Continuous practice may also be employed by passing the starting material through a reaction chamber in the presence of--.a fiow of hydrogen or hydrogen-containing gas. The flow of hydrogen is maintained so as topreclude substantial carbonaceous deposition. or polymerization. Gas fiows of in the order of 15,000-20,000 cubic feet per barrel material treated will prove satisfactory under certain conditions. However, higher or lower gas flows may be employed. All catalysts efiective in the presence of hydrogen may be employed separately or in admixture or in conjunction with the catalysts aforementioned. However, the hydrogen step may be practiced without catalysts. When employing very eflicacious catalysts, pressures only slightly above atmospheric may be employed. As a specific example of the more effective hydrogenation catalysts may be mentioned the oxides and/or sulfides of metals including halogens or derivatives thereof. These catalysts or others in any form or shape may be employed, as for instance extended on carriers, pelleted, comminuted, extruded or in any form or shape promoting surface contact.

In the final step of the process characterized by contacting the intermediate starting material with preheated inert gas, the final equalization temperature is selected between the limits of 300-750 C., as for example between 425 and 700 0., say 510 0., 525 C. or 535 C.

Minor changes may be made without departing from the spirit of the present invention.

I claim:

1. In the production of valuable liquids from the refined pitch produced by stripping high temperature coal tar to a point to produce a residual selected from the group consisting of pitch, semi-coke and coke, and fractionating the overhead material to recover a liquid useful as a woodpreservativa and a higher boiling fraction boiling predominantly above 355 0., the process which comprises: subjecting said higher'boiling fraction to the action of hydrogen for a period not-in excess of about three hours, whereby to avoid loss of newly induced low boiling fractions; stripping newly induced low boiling fractions from the hydrogen treated material; and increasing the boiling pointsof at least a chosen portion of said stripped fractions by subjecting same to the dehydrogenating action of a preheated inert gas in the absence of an added catalyst at a temperature nselected between the limits of about 300'-750 C.

2. In the production of valuable liquids from the refined pitch produced by stripping high temperature coal tar to a point to produce a residual selected from the group consisting of pitch, semicoke and coke, and fractionating the overhead material to recover a liquid useful as a wood preservative, and a higher boiling fraction boiling predominantly above 335 C., the process which comprises: subjecting said higher boiling fraction to the action of hydrogen for a period not vin excess of about three hours, whereby to avoid loss of newly induced low boiling fractions; strip- .ping newly induced low boiling fractions from the hydrogen treated material; increasing the boiling points of at least a chosen portion of said stripped fractions by subjecting same to the dehydrogenating action of a preheated inert gas in the absence of an added catalystat a temperature selected between the limits of about 300- 750 (2.; and fractionating the last named beneficiated material to segregate a solvent.

In the production of valuable liquids from the refined pitch produced by stripping high temperature coal tar to a point to produce a residual selected from the group consisting of pitch, semicoke and coke, and fractionating the overhead material to recover a liquid useful as a wood preservative, and a higher boiling fraction boiling predominantly above 355? C., the-process which comprises: subjecting said higher boiling fraction to the action of hydrogen for a period not in excess of about threehours, whereby to avoid loss of newly induced low boiling fractions; stripping newlyinduced-low boiling fractions. from the hydrogen treated material; increasing the boiling points of at least a chosen portion of said stripped fractions by subjecting same to the dehydrogenating action of a preheatedinert gas in the absence of. an added catalyst at a; temperature selected between the limits of about 300-750 0.; and fractionating the last named beneficiated material toprovide a solvent boiling preponderantly between 100 C. and 150 C. v

4. In the production of valuable liquid from the refined pitch produced by stripping high temperature coal tar to a point to produce a residual selected from the group consisting of pitch, semicoke and coke, andfractionating theoverhead material torecover a liquid useful as a, wood preservative, and a higher boiling fraction boiling predominantly above 355 C., the process which comprises: subjecting said higherboiling-fraction to the action of hydrogen at a pressure not; in excess of about 100 atmospheres and a temperature in excess of 300 C. for a period not in excess of about three hours, whereby to avoid loss of newly induced low boiling fractions; stripping newly induced low boiling fractions from the hydrogen treated material; and increasing the boiling points of at least a chosen portion of said stripped fractions by subjecting same to the dehydrogenating action of a preheated inert gas in the absence of an added catalyst at a, temperature selected between thelimits' of about 300750 C. 5. The process of claim 4 wherein the last named beneficiated material is fractionated to recover a solvent. 1 I V JACQUELIN E. HARVEY,-JR.v

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