US2291316A - Method of providing solvency induction - Google Patents

Description

July 28 1942 J. E. HARVEY, JR 2,291,316

METHOD OF PROVIDING SOLVENCY INDUCTION Filed March 14, 1941 www Patented July 28, 1942 UNITED STATES PATENT OFFICE MET'HGD OF PROVIDING SGLVENCY INDUCTION Application March 14, 1941, Serial No. 383,466

(Cl. IE6-"53) Claims.

This invention relates to the production of solvents.

More especially, the present invention relates to the production of solvents from hydrocarbons containing oxygenated compounds.

This application is a continuation in part of my application Serial No. 352,655, filed August 14, 1940, for Method of providing solvency induction, copending herewith, as to all matter cornmonto the two applications.

An object of the present invention is the production of solvents of lower boiling range from hydrocarbons of higher :boiling range, said hydrocarobns characterized by content of oxygenated compounds.

Another object of the present invention is the production of solvents of lower boiling range from liquid and solid 'hydrocarbons of higher boiling range, said liquid and solid hydrocarbons being characterized by the presence of oxygenatecl com-pounds.

Still another object of the present invention is the conversion of liquid and solid hydrocarbons, to the extent of a substantial percentage, into solvents of lower :boiling range; said liquid and solid hydrocarbons being characterized by content of oxygenated compounds.

A more specic object of the invention is the conversion of tars of aromatic content and fractions thereof, to the extent of `a substantial percentage, into lower boiling solvents of superior quality. Said tars and fractions thereof being characterized by the presence of oxygenated compounds.

Still another object of the present invention is the vsubjecting of tars of aromatic content'and fractions thereof characterized by oxygen content tothe step-wise action of hydrogen while contacting a catalyst adapted to influence the decomposition of said oxygenated compounds.

The tars forming suitable starting materials for vthe process of the present invention are tars of oxygen content and are derived from coal, wood, petroleum, gas and gases, and are characterized by aromatic content; more specifically gas house tar, water gas tar, tars derived from coal, as for instance, coke oven tar, and low temperature tar; aromatic tars of petroleum derivation, including gases. Selected fractions of the foregoing tars, as for instance, 4pitch or high boiling residues or fractions thereof, including stripped tars serve as suitable starting materials.

Viewed broadly, the present invention provides `a .process wherein, among other things, coal tar or the like is subjected to the action of hydrogen in step-wise manner under controlled conditions whereby the molecular complexes of the starting material are reduced, including in size, to provide if desired solvents of lowered and controlled Iboiling range, said solvents being characterized as having directly usable solvency as opposed to the high boiling fractions (molecular complexes) of said starting material whose solvency is not directly usable, or partially or totally absent.

It is now found that when converting tars or fractions thereof containing high molecular complexes, -characterized by content of oxygenated compounds, to solvents of superior solvency, that the induction of solvency is enhanced by provision of specic means of influencing the decomposition of said oxygenated compounds contained in the starting material when under the .influence of hydrogen.

The ,present invention provides, among other things, a method whereby tars and fractions thereof of oxygen lcontent are converted by the action .of hydrogen in step-wise manner to solvents of superior solvency, said conversion being lcharacterized by being effected in at least one cycle of hydrogen action in the liquid phase in the .presence of catalyti-c material that influences decomposition of oxygenated ycompounds contained in the starting material, while under the influence of hydrogen. By the specific provision of the inclusion of a catalytic material or materials adapted to influence decomposition of said oxygenated compounds, while subjected to hydrogen action, the process which induces solvency and converts aforenamed tars and fractions thereof of oxygen content in stepwise manner into superior solvents, is enhanced.

Included among those materials adapted to influence the decomposition of oxygenated compounds, vvhile holding the starting material containing said oxygenated compounds under the influence of hydrogen, are halides, halogens and derivatives thereof including substitution and addition products thereof.

The following examples will serve to illustrate the general principles upon which the practice of the present invention is based, as well as the process of the present invention, characterized by the inclusion of catalytic material or materials, hereinafter referred to as decomposition influencers, adapted to influence the decomposition of oxygenated compounds contained in the starting material while said starting material is subjected to the action of hydrogen.

The invention will be understood from the following description of illustrative steps comprising various methods of securing the objects of the invention, when read -in connection with the accompanying drawing wherein the figure is a diagrammatic sketch of an apparatus for carrying out a form of the process of the invention and wherein the nature of the step carried out in each chamber and the contents thereof are indicated by legend.

Example 1.-A high residue creosote having substantially 48% boiling above 355 C. and substantially 2% -coke residue is charged -to a high pressure autoclave and subjected to the action of hydrogen at 200 atmospheres pressure and a temperature of 400 C.; catalyst, molybdenum oxide and tin chloride; time of reaction, one hour. At the end of the hour period the beneficiated creosote is withdrawn from the autoclave and will be found to have reduced coke residue, speciiic gravity and viscosity. The beneciated material is then distilled to an upper limit of 250 C. to provide a distillate as an intermediate starting material. The intermediate starting material is then subjected to the further action of hydrogen wherein temperature is 475 C. and pressure 200 atmospheres vand the catalyst molybdenum oxide. The thus beneficiated material will be found to have an'increased solvency as compared to its intermediate starting material, and will be further characterized by having an increment of low boiling fractions in excess of fractional increment in the higher boiling range. The residue incidental to the above named stripping operation is recycled for further solvent production. The firstV action of hydrogen is characterized by preferential action on the high boiling range.

By the presence of the decomposition `influencer the step-wise induction of solvency is enhanced.

Example 2.-A coal tar, specific gravity 1.1641, coke residue in excess of 8% and boiling predominantly above 190 C. is passed through a high pressure reaction vessel while simultaneously flowing hydrogen therethrough at a temperature of 410 C. and 350 atmospheres pressure. Time of reaction is 75 minutes and a flow of hydrogen 12,000 cubic feet per barrel feed stock. The beneciated tar is distilled to an upper limit of 260 C. to provide the distillate as an intermediate starting material. The intermediate starting material is then passed through a high pressure reaction vessel while simultaneously owing hydrogen therewith. The catalyst is molybdenum sulfide, and the flow of hydrogen 6,000 cubic feet per barrel of feed stock; the time of contact is two minutes. The beneficiated material will be found to have a solvency in excess of its intermediate starting material and will be characterized by an increment of low boiling fractions in excess of fractional increment in the high boiling range.

Example 3.-A tar fraction of aromatic content, initial boiling point substantially 220 C. and having 50% residue in excess of 355 C. is subjected to the action of hydrogen while contacting a cobalt sulfide-tin chloride catalyst. Reaction is carried on for a period of one hour at 410 C. and a pressure of 400 atmospheres. The beneciated material will be found to have a lowered coke residue, specific gravity and viscosity and a condensation of boiling points toward the lowered boiling end. The beneflciated material is then distilled to an upper limit of 320 C. with the distillate serving as intermediate starting material. The intermediate starting material is subjected to the action of hydrogen at a temperature of 465 C. and a pressure of 200 atmospheres. The finally beneciated material will be found to have a solvency in excess of its intermediate starting material and will be further characterized by an increment of low boiling fractions in excess of fractional increment in the higher boiling range.

Example 4.-A coal tar fraction, specific gravity 1.23 and boiling at 355 C. is subjected to the action of hydrogen at 375 C. and 200 atmospheres pressure. 'Ihe catalyst is vanadium sulfide and iodoform and the time of reaction one hour. -The beneficiated pitch is again subjected to an Videntical cycle of hydrogenation. The twice beneiiciated pitch is distilled to an upper limit of 210 C. to provide a distillate as anintermediate starting material for the solvents of the present process. The distillate is then subjected to the action of hydrogen at 535 C. and a pressure of 200 atmospheres. The beneiiciated distillate will be found to have a solvency in excess of its intermediate parent material and will be further characterized by increment of low boiling fractions'in excess of fractional increment in the higher boiling range.

Example 5.--It has been discovered Ythat when subjecting certain mixtures of vrefined coal tar fractions to the action of hydrogen inaccordance with the present process for the'production of solvents and/or plasticizers that the formerly accepted teachingthat product increment, depolymerization and/or hydrogen absorption are linear functions of the time, is not followed.V

When subjecting a mixture of crude coal tar fractions boiling predominantly above 250 C. or 275 C. to the action ofhydrogen, research has disclosed that the newly induced'products, depolymerization and/or hydrogen absorption are linear functions of the time. As an example, when the above mixture of crude coal tar fractions is subjected to the action of hydrogen for 2, 5-, and 8-hour periods, the newly induced products, depolymerizationA and/or hydrogen absorption were 4linear functions of the time element. f

One of the preferred starting materials of the present process is a mixture of refined coal tar fractions boiling predominantly above 355 or 380 C. Such a starting material is conveniently the nal residue resulting from evaporating coal tar to dryness or substantial dryness and then stripping wood preservative from the distillate. This final residue mass of refined coal tar fractions is an especially suitable refined coal tar pitch to be used as starting material of the present process. However, in contradistinction to the mixture of crude coal tar fractions boiling predominantly above 250 or 300 C., when the aforenamed preferred starting material is subjected to the action of hydrogen for production of solvents and/or plasticizers, the newly induced fractions, depolymerization and/or hydrogen absorption are not, as described for the other mixture of crude tar fractions, linear functions ofthe time. A critical period of treatment by or with hydrogen exists, and which if exceeded causes loss of newly induced fractions', polymerization and/or lessened hydrogen absorption on certain fractions of the preferred starting material under treatment.

The critical time element because of the obvious possible variations in the characteristics of the aforenamed `refined coal tar 4pitch cannot be spoken of as an arbitrary gure. It can be stated, however, that if the rened co'al tar pitch were to be subjected to the action of hydrogen for such a length of time, which for other crude coal tar fractions would illustrate that the newly induced fractions, depolymerization and/or hydrogen absorption were linear functions of the time element, loss of induced products, polymerization and/or lessening of hydrogen absorption would occur. When treating the refined coal tar pitch by or with hydrogen, the critical time element is in the order of about three hours.

In the disclosures made herein and in the appended claims distillate removal of low boiling portions from the beneficiated material is considered the equivalent of fractional removal by gas movement, solvent action or the like. The converse also obtains.

A refined coal tar pitch chosen from the group boiling predominantly above, and above, 35.5v

C., characterized by content of oxygenated compounds and a coke residue in excess of substantially 2% is charged to a high pressure autoclave and subjected to the action of hydrogen at 300 atmospheres pressure and a temperature of 410,

C.; catalytic materials, molybdenum sulfide and iodoform; time of reaction two hours. At the end of the two hour period the beneficiated refined pitch is withdrawn from the autoclave and will be found to have reduced coke residue, spe-I cific gravity, viscosity and oxygen content.' The beneciated material is then distilled to an upper limit of 300 C'. to provide a distillate as an interinediate starting material. The intermediate starting material is then subjected to the further action of hydrogen wherein temperature is 485 C. and the pressure 200 atmospheres and the catalyst is an oxide selected from the group comprising the sixth and eighth periodic groups. The thus finally beneficiated material will be found to have an increased solvency as compared to its intermediate starting material, and will be further characterized by having an increment of low boiling fractions in excess of fractional increment in the higher boiling range. higher boiling range is meant, as an example, the upper half of the boiling range. The residue incidental to the above named stripping action may be recycled for further solvent production.

The first hydrogen action is characterized byl preferential action on the higher boiling range.

The finally beneficiated material of induced solvency may be employed en toto as a superior solvent, or it may be fractionated to provide solvents of varying boiling ranges, and the highest; boilers may be employed as plasticizers account their induced characteristics.

When subjecting the refined coal tar pitch to the action of hydrogen in accordance With the present process the first hydrogen action is con-. trolled at or below the critical time period. If"

the critical time period is exceeded there will occur loss of fractional increment, polymeriza tion and/or lowered hydrogen absorption. Thus,

when treating a refined coal tar pitch with hy,v 4-

drogen in accordance with the present process, the first hydrogen action must be controlled with regards to time of treatment so that fractional increment, depolymerization and/or hydrogen absorption are linear functions of the time ele, ment. The critical time period is in the order of about three hours, and the employment of a greater time element in the first hydrogen action will result in the ill or. ills above noted. Accordingly, when subjecting a refined coal tar pltchi By the,A

to the action of hydrogen in accordance with the present process, the time :period of the first hydrogen action is less than in the order of about three hours.

In conjunction with the decomposition influencers previously named, all catalysts effective in the presence of hydrogen for aforementioned purposes are usable, as for instance, chromium, molybdenum, vanadium, manganese, uranium, cobalt, copper and their compounds as suldes or oxides; promoted or not; with or without small amounts of alkali, acid, halid, or derivatives thereof. Small amounts of halogen or halogens, as such, or incorporated with other substances may be used; effective catalysts deposited on carriers, as for instance, gels, earths, carbon, or the like; in various shapes, as for instance, forms, extruded shapes or lengths, pellets, comminuted; mixed with other material possessing desired action or not; with or without material effecting splitting; catalysts with added halogen derivatives.

In step-wise action of hydrogen in the present invention, the rst action of hydrogen on the starting material is characterized by reduction of coke residue, specific gravity, and viscosity in the starting material. In the first cycle of hydrogen action pressures as low as atmospheres are usable as are temperatures as low as 200 C., however, higher temperatures and pressures are preferred, as for instance, temperatures of 35o-450 C. and pressures of in the order of or in excess of 200 atmospheres. Pressures and temperatures are, however, not restricted to any definite limitations inasmuch as hydrogen action that reduces the coke residue, specific gravity and viscosity of the starting material Will proceed at lowered temperatures and pressures. The desired temperatures and pressures are those that Will reduce coke residue, specific gravity and viscosity in a commercial manner. When using continuous operation in the first hydrogen cycle, flows of 10,000-15,000 cubic feet per barrel feed stock have proven satisfactory, however, higher and lower gas flows have proven effective.

In the last cycle of hydrogen action, as comprising a part of the present invention, for a given coordination of temperature and pressure as compared to the first cycle, the hydrogen flow in the last cycle is'less than the flow in the rst cycle. In the last cycle of hydrogen action pressures as low as 50 atmospheres are usable as are temperatures of as low as 300 C.; however, more elevated temperatures and pressures are preferred, as for instance, pressures of in the order of or in excess of 200 atmospheres and temperatures chosen from the range between 30D-750 C.

Aromatic tars of petroleum derivation or as produced from gas or gases serve as suitable starting materials. Tars or fractions thereof, at least once refined by hydrogen or other means also serve as starting materials.

By the term beneficiated as used herein and in the appended claims is meant the starting or intermediate starting material at least once subjected to the action of hydrogen in accordance to the present process.

Other catalysts or materials influencing `splitting or decomposition may be used in conjunction with aforesaid sulde catalysts.

In both cycles of hydrogen action the present process is predicated on so controlling the reaction conditions that ring structures are not opened with the rsubsequent formation of liquid chain or paraffin structures to the extent that the vsolvents of enhanced solvency of the present invention are impossible of manufacture.

In the first cyclic action of hydrogen, conditions are so controlled as to induce no substantial percentage of carbonaceous increment. When utilizing most of the starting materials, the first action of hydrogen is further characterized by the depolymerization of high molecular complexes. By the term high molecular complexes is meant those high boiling fractions especially susceptible to thermal degradation.

In the second cycle of hydrogen action periods as short as one minute or less at operating conditions have proven beneficial, however, longer periods may be used, as for instance, several minutes. As a, general rule, it may be said that the time element in the second cycle is that period necessary to provide final increment of low boiling fractions in excess of fractional increment in the higher boiling range, and to induce solvency.

The hydrogen supply used in the present process may come from any convenient source, as for instance, by the disassociation of methane. If desired, any diluting gas may be used in connection with the hydrogen.

When the starting material has been subjected to the rst cycle of hydrogen action that reduces coke residue, specific gravity and viscosity, the stripping of the benelciated mass may be effectedat -any point desired as for instance, at 200 C., or higher, or lower. Generally the point of stripping is determined by the boiling range desired in the product flowing from the nal action of hydrogen in the second cycle.

Within the limits of the boiling range of the finally beneciated material, solvents and/ or plast-icizers may be fractionated therefrom, as for instance, to provide substitutes for the boiling range or ranges of any of the following:

Benzol c '78-120 Toluol 100-150 Hi-flash naphtha 150-200 Heavy naphtha 150-290 Plasticizers 160-360 The residue incidental to aforesaid stripping action or any residue incidental to solvent or plasticizer recovery from the nally beneciated intermediate starting material may be recycled for further product production. By such recycling operation the coke residue inherent to the starting material can be made to substantially finally disappear.

Starting materials include tars and fractions thereof derived from wood, coal, and petroleum including gases of carbon content; as for instance, wood tar, pine tar, coke oven tar, gas house tar, water gas tar and synthetic aromatic tars derived from petroleumv sources including gases containing carbon.

Starting materials previously subjected to the action of hydrogen are suitable starting materials.

In the disclosures herein made the removing of low boiling fractions by gas movement or pressure release is considered the equivalent of distillation.

When reference is made to high molecular complexes contained inthe starting material, and when the starting material contains low boiling fractions that are not considered high molecular complexes, it is o-f course obvious that the high molecular complexes contained in the startingmaterial are to a certain extent depolystance, tars from which solvent oils have been removed. Viewed broadly, the starting materials of the present process are tars of aromatic Icontent, fractions of said tar more viscous than the starting material due to removal of low boiling fractions from the starting material, high 'boiling fractions and pitches.

The decomposition influencer which it is desired to have present in the reaction zone is generally taken between 0.1 and 4 or 5 per cent, based on the feed stock, and is preferably taken between 0.1 and 1.5 per cent.

Halogens, halids and derivatives thereof are employed for catalytic purposes noted in the foregoing; however, also may be employed substances furnishing under the process conditions a halogen or a hydrogen halid. Ammonium chloride may be employed, also halogen compounds of coal tar oils or the like, as for instance the iodides or bromides. Also may be employed acids, such as nitric, sulphuric, sulphonic, formic and acetic.

The addition of the decomposition influencer may be made prior to the entry of the feed stock into the reaction chamber, or at any suitable time, as for instance, after the charging stock has been heated.

Equivalent amounts of compounds furnishing halogen or hydrogen halid may be employed.

An especially attractive form of practicing the present process is to rst depolymerize the starting material with a solvent, as for instance, but not in -a restrictive sense, a refractory solvent. As an example of such solvent employment may be mentioned the depolymerization of the refined pitch by use of a suitable solvent. I'he solvent may be employed in quantity of up to volume for volume, or more. After the depolymerizing step, the solvent and solute are then subjected to the action of hydrogen in accordance with the process. Solvents having the power to place at least a substantial percentage of the starting feed, as for instance the refined pitch, in solution are preferred; such solvents may conveniently be secured from the tar or petroleum industries.

Gas flows in the second hydrogen action are always held below the hydrogen flow of the first action. A few trials with any of the intermediate starting materials will determine the ow necessary to induce solvency; said ows are generally chosen from below 8,000 cubic feet per barrel feed, as for instance in the range below 5,000 cubic feet.

The evaluation of solvent power is conveniently accomplished by finding the Well-known aniline point or kauri-butanol number. The evaluation of plasticizing properties is conveniently accomplished by recourse to methods suggested in chapter VI, The technology of solvents," by Dr. Otto Jordon, Mannheim, Germany, translated by Alen D. Whitehead, Chemical Publishing Company of New York, Incorporated, New York, New York.

Minor changes may be made in the steps of the process within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. In the production of a solvent from the refined pitch produced by stripping high temperature coal tar to at least about substantial dryness, 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 cornprises: subjecting said higher boiling fraction to the action of a relatively high ow of hydrogen at a pressure in excess of 50 atmospheres and a temperature between about 350- 450o C. while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof for a period not in excess of about three hours, whereby to avoid loss of newly induced fractions; stripping newly induced fractions from the beneciated material; and subjecting at least a portion of said stripped fractions to the action of a relatively low iiow of hydrogen at a pressure of at least about 50 atmospheres and a temperature between 465- 535 C. to provide an increment of fractions in the lower boiling range in excess of fractional increment in the higher boiling range to produce a solvent. Y

2. In the production of a solvent from the rened pitch produced by stripping high temperature coal tar to at least about substantial dryness, 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 a relatively high now of hydrogen while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof for a period not in excess of about three hours, whereby to avoid loss of newly induced fractions; stripping newly induced fractions from the beneciated material; and subjecting at least a portion of said stripped fractions to the action of a relatively low flow of hydrogen to provide an increment of fractions in the lower boiling range in excess of fractional increment in the higher boiling range; and fractionating the last named beneciated material to segregate a solvent.

3. In the production of a solvent from the refined pitch produced by stripping high temperature coal tar to at least about substantial dryness, 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 a relatively high flow of hydrogen while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof, for a period not in excess of about three hours, whereby to avoid loss of newly induced fractions; stripping newly induced fractions from the beneciated material; and subjecting at least a portion of said stripped fractions to the action of a relatively low flow of hydrogen to provide an increment of fractions in the lower boiling range in excess of fractional increment in the higher boiling range; and fractionating the last named beneciated material to provide a solvent boiling preponderantly between and 150 C.

4. In the production of a solvent from the refined pitch produced by stripping high temperature coal tar to at least about substantial dryness, and fractionating the overhead material to recover a liquid useful as a wood preservative, and a higher boiling fraction boiling predominantly about 355 C., the process which comprises: subjecting said higher boiling fraction to the action of a relatively high iiow of hydrogen while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof at a pressure in excess of 50 atmospheres and a temperature selected between the limits of about 350-450o C. for a period not in excess of about three hours, whereby to avoid polymerization; stripping newly induced fractions from the beneciated material; and subjecting at least a portion of said stripped fractions to the action of a relatively low flow of hydrogen at a pressure of at least about 50 atmospheres and a temperature between 465- 535 C. to provide an increment of fractions in the lower boiling range in excess of fractional increment in the higher boiling range to produce a solvent.

5. In the production of a solvent from the refined pitch produced by stripping high temperature coal tar to at least about substantial dryness, 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 a relatively high flow of hydrogen while contacting a catalyst selected from the group consisting of halogens, halids and derivatives thereof at a temperature and pressure in excess of about 400 C. and about 50 atmospheres, respectively, for a period not in excess of about three hours, whereby to avoid lowered hydrogen absorption; stripping newly induced fractions from the beneflciated material; and subjecting at least a portion of said stripped fractions to the action of a relatively low flow of hydrogen at a pressure of at least about 50 atmospheres and a temperature between 465- 535 C. to provide an increment of fractions in the lower boiling range in excess of fractional increment in the higher boiling range to produce a solvent.

JACQUELIN E. HARVEY, JR.

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