US2499820A - Thiourea-hydrocarbon complexes - Google Patents

Thiourea-hydrocarbon complexes Download PDF

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US2499820A
US2499820A US73018247A US2499820A US 2499820 A US2499820 A US 2499820A US 73018247 A US73018247 A US 73018247A US 2499820 A US2499820 A US 2499820A
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thiourea
hydrocarbons
hydrocarbon
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complexes
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C13/00—Cyclic hydrocarbons containing rings other than, or in addition to, six-membered aromatic rings
    • C07C13/02—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof
    • C07C13/08—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a five-membered ring
    • C07C13/10—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a five-membered ring with a cyclopentane ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C13/00—Cyclic hydrocarbons containing rings other than, or in addition to, six-membered aromatic rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C13/00—Cyclic hydrocarbons containing rings other than, or in addition to, six-membered aromatic rings
    • C07C13/02—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof
    • C07C13/16—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a six-membered ring
    • C07C13/18—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a six-membered ring with a cyclohexane ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
    • C07C7/152—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by forming adducts or complexes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C9/00—Aliphatic saturated hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C9/00—Aliphatic saturated hydrocarbons
    • C07C9/14—Aliphatic saturated hydrocarbons with five to fifteen carbon atoms
    • C07C9/16—Branched-chain hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
    • C10G31/06—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by heating, cooling, or pressure treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00—Systems containing only non-condensed rings
    • C07C2601/06—Systems containing only non-condensed rings with a five-membered ring
    • C07C2601/08—Systems containing only non-condensed rings with a five-membered ring the ring being saturated

Definitions

  • This invention relates to new hydrocarbon complexes, and more particularly pertains to complexes of hydrocarbons and thiourea, as well as to the method of forming them.
  • Barrer U. S. Patent 2,306,610
  • Sachanen Chemical Constituents of Petroleum, page 187 (1945)
  • Extractive distillation has been utilized, according to Griswald and Van Berg (Ind. Eng. Chem.
  • Diesel engine fuels involves the isolation of fuel oils having high octane numbers and Diesel indices, empirical ratings directly related to the type and quantity of certain hydrocarbon fractions present therein.
  • a process capable of isolating preferred fractions from low grade stocks would be of substantial value in improving Diesel fuel production.
  • hydrocarbons having substantially no color.
  • the decolorization of hydrocarbons generally involves a series of steps involving complicated apparatus, excessive labor costs and extended processing time. Any method which was relatively simple and which would effect decolorizing to the desired degree would be of value to the petroleum, naval stores and coal tar industries.
  • Another problem which has been inadequately solved up to the present time is the removal of gum and resin bodies which have been formed by oxidation or other means. Such purification usually involves complicated equipment. A oneor two-step process for improving gum-containing gasoline is especially required.
  • the complexes appear to be molecular in character, both the hydrocarbon and the thiourea being readily recoverable therefrom in substantially pure form.
  • the complexes therefore, appear to be similar to compounds containing a solvent of crystallization, and possibly may be formed by hydrogen bonding.
  • the ratio of mols of thiourea to mols of hydrocarbon varies with the molecular weight of the hydrocarbon and with the method of forming the complex.
  • the complexes may be quite different from those described above.
  • they may contain other ratios of thiourea to hydrocarbon, and/or they may contain a solvent of crystallization, such as alcohol or water.
  • a solvent of crystallization such as alcohol or water.
  • thiourea thiourea than those above, and usually have an approximate thiourea hydrocarbon weight ratio of 1:1. On a mol basis, complexes so formed usually will have a molar ratio of 2:1:1 thiourea hydrocarbon solvent. When using the solvent separation method more fully described hereinafter the ratio of thiourea to hydrocarbon may be even less than in the several types described above.
  • the complexes of hydrocarbons and thiourea are of two general types: those which are crystallin and those which are non-crystalline, usually fluid or oily in character.
  • the crystalline type complexes are well defined in structure, having measurable angle and face characteristics.
  • the crystalline complexes of the individual hydrocarbons have sharp melting points, resolution into the two components thereof usually taking place after a short heating period, in the absence of other factors affecting the crystalline structure. While the crystal structure varies within wide limits, the complexes are generally needlelike in form, and can be made either in very small, short form or in the proper environment can be made to form coarse,-easily fllterable The latter are preferred for production on a large scale, since filtration problems thus are minimized.
  • the thiourea-hydrocarbon complexes are insoluble in water, or are soluble therein only to a slight extent. Further, this low water-solubility decreases with the ratio of thiourea to hydrocarbon in the complexes.
  • the crystalline complexes are only sparingly soluble in organic materials such asalcohols, glycols and inert hydrocarbons.
  • the noncrystalline complexes while substantially insoluble in aqueous media, are somewhat soluble or dispel-sable in some media, particularly inert hydrocarbons.
  • crystalline complexes of thiourea, and hydrocarbons may be formed by treating either single hydrocarbons or mixtures thereof with thiourea. While the complex formation is simplified when only single hydrocarbons are so treated, generally the practical commercial applications of the principles involved as described herein, are separations of mixtures of hydrocarbons into desired components or fractions.
  • hydrocarbons which form complexes with thiourea When complex formation is conducted at or below room temperature the two'types of hydrocarbons which form complexes with thiourea most readily are the isoparafi'ms and naphthenes.
  • Other types of hydrocarbons which form complexes with thiourea are those having a predominating member which is an isoparafiin radical or a naphthene radical, such as alkaryl hydrocarbons wherein at least one alkyl group is an isoparaflin radical of about six or more carbon atoms.
  • Isoparaffins which form complexes with th ourea include isobutane, isopentane, 2,2-dimethylpropane, isohexane, 2,3-dimethylbutane, 2-methylpentanc, 3-methylpentane, 2-ethylbutane, 2- ethylpropane, 1,1-climethylpentane, 1,2-d methy1- pentane, l3-dimethylpentane, 1,4-dimethylpen- -tane, Z-et'nylpentane, 3-ethylpentane, 2-n-propylbutane, 2-isopropylbutane, 2-methy1hexane, 3- methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4 dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimet-hylbutane,
  • Typical species of this group include cyclopropane, methylcyclopropane, 1.l-dimethyl-cyclopropane 1 2-dimethylcyclopropane, ethylcyclopropane, 1,1,2-trimethylcyclopropane, 1,2,3-trimethylcyclopropane, 1- methyl-2-ethylcyclopropane, propylcyclopropane, l-methyl 2 propylcyclopropane, cyclobutane, methylcyclobutane, ethylcyclobutane, 1,2-dimethylcyclobvtane.
  • propylcyclobutane isopronylcyclo butane, 1.2-diisopropylcyclobutane, 1,2-dimethyl- 3,4-diethylcyclobutane, 1,1,2,2-tetramethyl-3,4- diisopropylcyclobutane, cyclopentane, methylcyclopentane, 1,1-dimethylcyclopentane, 1,2-dimethylcyclopentane, 1,B-dimethylcyclopentane, ethylcyclopentane, propylcyclopentane, isopropylcyclopentane, 1,1,3-trimethylcyclopentane.
  • Iso-olefins which form complexes with thiourea include monoiso-olefins such as'2,3-dimethyl-l-butene, 3-methyl-2-ethyl-l-butene, 2,6-dimethyl-l-heptene, 2,3,4,4-tetramethyl 1 pentene, etc., and diiso-olefins such as 2,3-dimethyl- 1,3-butadiene, etc.
  • Cyclo-olefins which may be separated by the present process include 2,3-dimethyl-1-cyclopentene, 1-ethyl-2-methyl-1-cyclohexene and cyclodiolefins such as 3,3-dimethy1-1,4-cyclohexadiene and terpenes such as alpha-pinene.
  • hydrocarbon or mixtures thereof with which a thiourea complex is to be formed may be contacted with thiourea either in the presence of a hydrocarbon solvent or diluent or in the absence thereof.
  • Solvents are particularly practical when the hydrocarbon is solid at the temperature at which complex formation is to occur, although such formation may be conducted by treating the melted hydrocarbon (such as paraffin wax) if the melting point is relatively low.
  • Hydrocarbon diluents or solvents are regarded, for the purpose of this discussion, as any material which does not readily form a crystalline complex with thiourea at the temperature and under the other conditions of contacting, even though they may form such complexes therewith under other sets of conditions.
  • the contacting temperature is about 50 C.
  • the preferred diluents or solvents are other hydrocarbons, that is, hydrocarbons which are relatively inert toward thiourea under the contacting conditions.
  • Suitable hydrocarbons for this purpose are normal hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, dodecane and mixtures thereof, as well as aromatics such as benzene, toluene, xylenes, etc.
  • the solvent or diluent may be present as an impurity, such as in cracked gasoline.
  • the gasoline is treated with thiourea in order to isolate isooctane and other hydrocarbons having a high octane rating, while the normal paraflins and aromatics usually present therewith constitute a diluent for the reaction.
  • a diluent or solvent for the hydrocarbons is desirable in that, upon treatment of such a hydrocarbon mixture a fllterable slurry of the complex in the diluent is formed, rather than a substantially solid mass of the complex. Subsequently, the complex may be separated from the slurry, as more particularly described thereinafter, and is readily available for purification and/or for regeneration of the components of the complex, also more fully described later.
  • a diluent active hydrocarbon ratio of at least about 1:1. From a practical standpoint, it usually is diflicult to satisfactorily separate a complex from a mixture containing a ratio of diluent to active hydrocarbon greater than about 25:1, although such separations are possible under special conditions, especially when the temperature during thiourea contacting and/or during crystallization is sufliciently low.
  • a thiourea solvent for the purpose of contacting thiourea with hydrocarbons, either in the presence or absence of a hydrocarbon, a thiourea solvent also may or may not be used. Preferably enough of a thiourea solvent is present so that at least a minor amount of the thiourea is in solution at all times. Alternatively, the thiourea may be contacted with hydrocarbons while it is completely in solution. When this latter condition is used it is a preferred practice to employ a substantially saturated solution of thiourea, although more dilute solutions thereof may be utilized under conditions to be described more fully hereinafter.
  • thiourea solvent present during complex formation has a powerful effect upon the results obtained. It has been discovered, in accordance with one phase of the present invention, that by choosing special thiourea solvents or mixtures thereof a predetermined fraction or group of hydrocarbons will form thiourea complexes. For example, by using an aqueous alcoholic thiourea solvent for the thiourea, and varying the ratio of water to alcohol, an extremely close control is obtained over the type of hydrocarbon which will form complexes with the thiourea. This phenomenon may be utilized, for example, in the treatment of isomerization mixtures, where substantially complete removal of isoparaffins is essential before recycling unreacted material back through the catalyst tower.
  • the thiourea solvent may be adjusted or chosen so that only partial removal of the active hydrocarbons is effected.
  • a thiourea sol-' vent which is substantially immiscible with the medium from which thiourea-hydrocarbon complexes are to be obtained.
  • Partiiularly useful solvents for this purpose are water, the lower monohydric alcohols and the lower polyhydric alcohols such as the glycols. Mixtures of these solvents are useful for the close control of complex formation discussed above, and aqueous alcoholic (especially water methyl alcohol) mixtures are preferred, since they are easily recoverable, low in viscosity, contain no detrimental color or other impurities, and are good solvents for thiourea but are substantially immiscible with hydrocarbons and hydrocarbon mixtures of nearly all types.
  • the ratio of thiourea to hydrocarbons capable of forming separable complexes therewith may vary within wide limits, dependent upon the type of complex desired, the rate of complex formation necessary for efficient operation, the temperature of the reaction, the dilution of the active hydrocarbons, the dilution of thethiourea, and other factors affecting the operation. It is preferred practice, when a maximum removal of active hydrocarbons is desired, to contact the .thiourea.
  • complexes may be formed having varying amounts of thiourea combined in molecular complex with the hydrocarbons.
  • temperature or other conditions during complex formation are such that about three mols of thiourea combined with about every four carbon atoms of the hydrocarbon, it is preferred'practice to contact the hydrocarbon with an amount of thiourea somewhat in excess of this ratio.
  • crystalline complexes are formed having thioureazhydrocarbon ratios from about 1:1 to about 2:1, amounts of thiourea in excess of these respective ratios should be used if complete complex formation is desired in the minimum length of time.
  • thiourea treatment of active hydrocarbons may take place in a single stage, at times it is preferable to cause complex formation in a series of stages, using either a constant concentration of thiourea solution in each stage to form successive batches of the same complex, or varying the thiourea solution concentration to obtain different complexes in each stage.
  • a constant concentration of thiourea solution in each stage to form successive batches of the same complex
  • varying the thiourea solution concentration to obtain different complexes in each stage.
  • the temperature at which thiourea is contacted with hydrocarbons is an important factor in determining the extent of complex crystallization or separation of specific hydrocarbons, as well as in determining what hydrocarbons will form separable complexes with thiourea. Moreover, the temperature at which complex formation takes place determines the ratio of thiourea:hydrocarbon necessary to form a complex.
  • the complex formed under the above conditions usually will be of sufficient bulk to be readily separable from the mixture.
  • the mixture of hydrocarbons which form complexes with thiourea at a given temperature includes undesirable specific members or fractions, it is possible to depress or even eliminate said fractions from crystallizing with thiourea simply by changing the temperature of contact so that the undesirable fractions remain in solution while the desirable fraction crystallizes out as a complex with thiourea.
  • This phenomenon may be utilized in' a variety of processes wherein the mixture of hydrocarbons is passed through a series of temperature gradients. For instance, after the step described in the paragraph above has been carried out, it is possible to lower the temperature, contact the hydrocarbon mixture with thiourea, and take out a second fraction.
  • This system of fractional crystallization is subject to extremely close control, and thus permits remarkably accurate fractiona tion of a mixture into its individual components or types of components.
  • hydrocarbons crystallize more readily with thiourea when a complex is formed which has a minimum thiourea content and/ or solvent of crystallization. For these cases it is advisable to warm the hydrocarbons with thiourea until such a complex is formed.
  • Another important controlling feature of the process of the present invention is the manner in which the hydrocarbon or hydrocarbon mixture is contacted with thiourea.
  • the contacting step variations may be related in nomenclature to catalytic treatments of petroleum prod- 1. Concurrent fluid processes, whereby a solution of thiourea is introduced into the hydrocarbon feed line.
  • Fluid fixed bed processes whereby the hydrocarbon is passed through a stationary column of thiourea solution.
  • Moving bed processes whereby solid thiourea proceedes to move countercurrently to the hydrocarbon feed.
  • Emulsion processes whereby solutions of thiourea are emulsified, at least momentarily with the hydrocarbon feed.
  • the hydrocarbon feed contains a high proportion of hydrocarbons which will crystallize with thiourea, it is possible to allow only partial crystallization at any given time, with several stages of filtration.
  • the time and degree of crystallization may be controlled, as described hereinbefore, by adding thiourea solution at more than one point in the system, by temperature control, by control of the concentration of thiourea, or by other means.
  • the second means of contacting is especially suitable for the complete utilization of thiourea solutions and for extractive crystallization of relatively minor amounts of active hydrocarbons in the presence of a correspondingly large amount of inert hydrocarbons or other diluent.
  • suitable equipment includes a make-up tank for thiourea solution, a contacting tower with hydrocarbon feed entering at the bottom and thiourea solution being introduced from the top, an optional crystallizing area (crystallization may take place in the contacting tower), a separation area such as a settling tank or centrifuge, recovery means for the railinate, spent thiourea solution and means for separating the hydrocarbon from its crystalline complex.
  • Countercurrent fluid ex traction processes are especially adaptable for recycling steps, either for the thiourea so ution or partially extracted hydrocarbon or hydrocarbon mixture. It may be used, for example, in conjunction with an alkylation process, fractions be ing removed by crystallization with thiourea in order to separate the various types of alkylates present in the mixture coming from the alkylation system.
  • the fluid fixed bed processes are especially use ful where a simple flow plan is desirable, since the essential feature of such a process is a stationary column of thiourea solution.
  • the latter is preferably separated from the contacting tower to allow simplification of equipment design,'but
  • the contacting tower may be constructed so as to be suitable for settling and crystal removal if such is desired.
  • a clean-out or draw-off valve at or near the bottom of the tank.
  • a preferred alternative to cope with the situation is the substantially continuous introduction of solid thiourea and/or concentrated thiourea solution into the main body of the column, such as by a feeder line controlled automatically or manually, as desired.
  • Another system of contacting thiourea with hydrocarbons is the solid fixed bed process. whereby the hydrocarbon feed is passed through a fixed bed of solid thiourea.
  • Such a process may operate under special conditions in the absence of a. thiourea solvent, but it is preferred practice to introduce a controlled amount of water into the system at the time of or prior to contacting thiourea with the hydrocarbon. In effect, this produces a saturated solution of thiourea in situ.
  • the thiourea solvent be introduced into the hydrocarbon prior to contacting with thiourea, and that it be finely and uniformly distributed therethrough, if necessary by use of an emulsifying agent, but preferably in the latters absence.
  • the solid fixed bed system When the solid fixed bed system is employed it is preferable for continuous operation to maintain the temperature and other contact conditions such as rate of flow so that crystallization does not occur in the bed. Thus it is better to provide a crystallizing area wherein the hydrocarbons and fluid complex are received from the contacting zone, and in which crystallization may occur, followed by separation of thecrystals from any diluent present.
  • the solid fixed bed will diminish in size and effectiveness unless additional solid thiourea is introduced.
  • a convenient method of doing this is to introduce the solid thiourea into the hydrocarbon feed as it enters the contacting zone, but under conditions such that crystallization with the hydrocarbon does not occur.
  • the moving bed type of process may be utilized, wherein solid thiourea moves concurrently or countercurrently with the hydrocarbon feed.
  • This method is easily applied and has the advantage that a constant and controlled amount of thiourea is always present.
  • water or alcohol is present as an internal dispersion in the hydrocarbon, having been distributed therethrough prior to contacting with thiourea.
  • complex formation may be conducted in the absence of a thiourea solvent, or contact of the thiourea and hydrocarbon may be followed by introduction of water. It is preferable to remove most of the excess solid thiourea prior to allowing crystallization to occur.
  • the moving bed process is adapted for combination with the fixed bed process, whereby solid thiourea is introduced into the hydrocarbon stream and eventually reaches the fixed bed of thiourea.
  • an inert col- 13 loid or other dispersing agent to keep water and/or thiourea uniformly and finely distributed throughout the hydrocarbon.
  • the colloid is coagulable or otherwise removable at a late stage in the process, so that the hydrocarbon products are not contaminated therewith.
  • a slurry process may be employed, combining the fluid processes and the moving bed process. This may be accomplished by havin an entirely concurrent system, or by combined systems, such as passing solid thiourea countercurrently to a mixture of the hydrocarbons and thiourea solution, or by passing thiourea solution countercurrently to a mixture of solid thiourea and hydrocarbons.
  • Solvent extraction processes involve the use of a lean solvent for the complexes from which various fractions may be extracted by the use of better solvents therefor. It will be understood that these types of contacting processes are only representative of the various means whereby thiourea may be reacted with hydrocarbons, and furthermore that combinations and modifications of the above processes may be made in order to obtain a particular product.
  • the complexes so formed must be separated from the main body of hydrocarbons, diluents, excess thiourea solution, impurities, etc. This may be accomplished in various ways, such as by decantation, settling, filtration or centrifuging. Decantation and settling are especially useful when the crystalline complexes are relatively heavy and separate sharply and readily from the other components of the system. When settling is employed it is preferable to allow it to take placein a settling tank with continuous or semi-continuous withdrawal of efiluent from the top and complex at the bottom. Alternatively, the complex may be separated as a suspension in an aqueous phase and thereafter subjected to regeneration, either with or without a filtration step.
  • the hydrocarbon mixture comprises a heavy oil, such as a lubricating oil or Diesel oil
  • settling and decantation are usually insuflicient by themselves to produce satisfactory separation.
  • centrifuging or filtration usually are necessary, either alone or supplementary to decantation and/or settling.
  • An eflicient method comprises allowing settling for the removal of the bulk of the crystalline complex, followed by filtration of the'efiiuent, which contains residual crystals held in suspension due to their finely divided form or the viscosity of the liquid components of the mixture.
  • the complex may be purified by washing with a relatively inert material such as a normal or aromatic hydrocarbon (pentane, hexane, heptane, benzene, toluene, etc.). It is a preferred practice during any purification step to keep temperatures as low as is practical, consistent with the prevention of losses of the complex by solution in the wash liquors.
  • a relatively inert material such as a normal or aromatic hydrocarbon (pentane, hexane, heptane, benzene, toluene, etc.).
  • This method is particularlyadapted to the decomposition of complexes which contain a solvent of crystallization, such as water or alcohol.
  • a solvent of crystallization such as water or alcohol.
  • the heated crystals upon heating, form two layers, one of which contains the hydrocarbons the other being a solution of thiourea. The latter then may be separated from the hydrocarbons and recycled for the preparation of additional complexes.
  • a second method of decomposition comprises dry distillation, wherein the above method of dry heating is combined with a distillation step.
  • This modification is especially useful where relatively volatile hydrocarbons are involved.
  • this method may be used as a means of still further fractionating the hydrocarbons. As they are recovered by dry heating, a mixture of hydrocarbons is obtained, assuming that more than one hydrocarbon is present. But by adding a distillation step to the dry heating, the hydrocarbons are easily recovered as a series of fractions. At times itis desirable to distill the entire hydrocarbon layer, leaving nothing but thiourea or a solution thereof in the still. Again, only a portion of the desired product need be recovered by distillation, the remainder being obtained by, separation from the thiourea.
  • Another method of regenerating hydrocarbons from their complexes involves dry heating while hot dry gases are passed through the mixture at such temperatures and under such pressures as will permit the hot gases to remove at least a portion of the hydrocarbons, This method is especially valuabl where hydrocarbons are present which are somewhat subject to thermal decan be separated as described above. Furthermore, due to the presence of the modifying composition. Preferably the gases used for this substantially inert at the distillation and highly volatile at room temperawhile carbon dioxide purpose are temperature ture. Nitrogen is preferred, also may be used.
  • steam distillation is a preferred method for hydrocarbon regeneration. By this means substantially lower temperatures are necessary for hydrocarbon recovery, and decomposition of thiourea and other components of the mixture is held to a minimum. Steam distillation is particularly applicable to the recovery of hydrocarbons having high boiling points or which would carbonize to a certain extent if distilled by dry heat alone. The use of steam distillation, particularly using dry steam, also facilitates the recovery and/or purification of the regenerated thiourea, since a portion of the steam condenses and acts as a solvent for thiourea. The solution of thiourea thus formed is immediately available for recycling in a continuous or semi-continuous process.
  • Another method of hydrocarbon regeneration comprises the addition of a thiourea solvent to the crystalline complex.
  • Suitable solvents for this purpose are water, alcohols or glycols, and water is preferred, although aqueous alcohol also is satisfactory. It usually is necessary to apply some heat in order to decompose the complex. Upon mild heating, the stratification described above is evident, a solution of the regenerated thiourea separating from the layer of the regenerated hydrocarbons. If it is necessary to fractionate the hydrocarbons, it is preferred practice to remove them from the thiourea solution and then subject the mixture to fractional distillation.
  • a further preferred means of regenerating hydrocarbons from their thiourea complexes involves the addition of a hydrocarbon solvent, such as ether, to the complex, preferably followed by mild heating under pressure.
  • a hydrocarbon solvent such as ether
  • This method is particularly useful when the hydrocarbon to be regenerated is a highly viscous liquid or a wax-like solid 'at room temperature.
  • the thiourea which separates can be filtered or otherwise disposed of leaving a solution of the hydrocarbon.
  • the last two methods can be combined for example when the regenerated thiourea is to be recycled and the regenerated hydrocarbon is difficult to handle except as a solution.
  • One modification of the present process comprises the addition of compounds such as ethanolamines or acetamide to an alcoholic solution of thiourea, following which the mixture of hydrocarbons is treated therewith.
  • the isoparaflins and cycloparafiins form crystallin complexes with thiourea and agent in the alcohol, the normal parafiins separate therefrom as an immiscible layer, while the aromatics dissolve in the alcohol. Thereafter the two liquid layers may be separated and the aromatics and normal parafllns separately recovered.
  • This latter process may be varied by treatment of the hydrocarbon mixture with alcoholic ethanolamines or acetamides prior to treatment with thiourea.
  • the aromatics may be removed from the system prior to thiourea complex formation.
  • the rafllnate i. e. the fraction of a hydrocarbon oil not forming a complex with thiourea, may be treated with alcoholic acetamide or ethanolamine subsequent to thiourea complex separation, so that aromatic may be separated from the normal parafiins.
  • a versatile and useful modification of the process of the present invention is the'combination therewith of treatment of the hydrocarbon mixture with urea.
  • the latter forms complexes with hydrocarbons of normal structure, both normal parafiins and normal olefins, but fails to form complexes with aromatics or isoparafiins.
  • a further method for the separation of hydrocarbon mixtures into its component parts comprises initially treating the mixture with thioureaso as to separate the isoparaflins and cycloparaffins from the normal hydrocarbons and aromatics. If the rafiinate contains a preponderance of aromatics from which the normal paraflins must be separated, it should be treated with an aqueous or alcoholic solution of urea, separating the crystalline complexes, thus leaving substantially pure aromatic hydrocarbons. If the rafiinate comprises normal hydrocarbons contaminated with minor proportions of aromatics, it should be treated with an aromatic hydrocarbon solvent such as aniline, etc., or with an alcoholic solution of acetamide, so as to solvent extract the aromatics, leaving pure normal hydrocarbons.
  • an aromatic hydrocarbon solvent such as aniline, etc., or with an alcoholic solution of acetamide
  • a modified process comprises heating a hydrocarbon mixture with an aqueous solution of thiourea at a temperature above about 75 C. At these elevated temperatures the reaction mixture eventually separates into two layers, one containing the ,hydrocarbons and a major proportion of the complex, while the other is an aqueous layer containing a major portion of thiourea and a minor amount of a hydrocarbon complex.
  • the complex recovered from the first layer has a minimum thiourea hydrocarbon ratio, that is, about 2:1 on a molar basis, while the small amount of complex recovered from the aqueous layer has a molar ratio of about 6:1.
  • Another means of producing complexes having low thiourea hydrocarbon ratios is by heating the hydrocarbons with thiourea in the presence of only a minor amount of water or alcohol at temperatures from about 50 C. to about 75 C. Within this range complexes are formed which have low ,thiourea hydrocarbon ratios, and which usually contain some solvent of crystallization. Layer separation usually does not occur, the complex being recovered upon cooling to produce crystallization.
  • Multi-stage Processes may be used for meeting special conditions and for effecting separation of closely allied types of hydrocarbons. For example, it is advantageous to have a resonably large fluid phase relative to the amounts of crystalline complex, since such a condition will facilitate handling, especially during a filtration step. If the hydrocarbons to be treated with thiourea contain a large proportion of those which will form crystalline complexes, a single complete crystallization may result in a practically solid mass, with any inert hydrocarbons and unreacted thiourea occluded on the crystals. In order to avoid obtaining such a contaminated mass, it is advisable to modify the process so that only partial crystallization takes place at any one time.
  • Another means of producing gradual or stepwise crystallization is by temperature control. It has been ascertained that each hydrocarbon has a temperature above which crystallization will not occur, or will take place only at a reduced rate. Further, it has been found that with any given complex, the lower the crystallizing temperature the greater is the amount of complex which crystallizes out. Moreover, it has been found that each complex has a critical temperature above which itwill not crystallize out of a given reaction mixture.
  • the mixture of hydrocarbons may be treated with thiourea below the critical reaction temperature of the second type. After removing the resulting complex, the hydrocarbon mixture may be heated with thiourea to a temperature at which the second type will react, thus forming a complex uncontaminated with that of the more reactive hydrocarbon.
  • the critical temperature of crystallization of each hydrocarbon complex may be utilized to separate or fractionate a mixed product.
  • the temperature may be adjusted so that only one type crystallizes.
  • the filtrate may be cooled in order to cause crystallization of further types of complexes.
  • Another means of controlling crystallization is by varying the concentration of thiourea in its solvent, as outlined earlier in this sepcification.
  • advantage may be taken of this by contacting a hydrocarbon mixture with a thiourea solution and removing the complex so formed. Subsequently, the filtrate may be treated with thiourea solution of a greater or less concentration in order to form complexes of different hydrocarbons.
  • Choice of solvent for either thiourea or hydrocarbons has been found to affect the type of complex formed and the extent to which a given complex will crystallize.
  • a solvent such as ether may be added to the filtrate. Since some of the hydrocarbon complexes are less soluble in ether-containing mixtures, fractional crystallization will occur, enabling the recovery of another fraction of crystals.
  • hydrocarbons such as triptane
  • Some hydrocarbons may be separated substantially completely from mixtures containing them. Others may be extracted from their mixtures to the extent of 50- 9570. In the latter case, the filtrate may be mew-camera ther treatment, either with'thiourea or with other reagents. Following extraction of certain hydrocarbons from their mixtures, the latter may be subjected to distillation, treatment with urea, treatment with a solvent for aromatics, etc;, in order to concentrate the active hydrocarbons be fore further treatment with thiourea.
  • thiourea may be utilized to improve isomerization processes.
  • a hydrocarbon feed is heated and isomerized in the presence of a catalyst such as hydrogen chloride.
  • the mixture so obtained comprises normal hydrocarbons and their branched isomers. Under a given set of conditions there is always a maximum extent to which isomerization will occur.
  • the mixture is subjected to fractional distillation.
  • the normal hydrocarbons are then returned to l9 feed for another isomerization treatment.
  • the fractional distillation always allows a minor amount of the isomerised product to remain in the normal feed.
  • the thiourea process may be used, thus producing a feed substantially free of all but normal hydrocarbons.
  • the thiourea treatment may be applied before the feed reaches the isomerization reactor and/or after separation of isomerized product from unreacted feed stock by fractional distillation. Since the proportion of isomers as compared to normal hydrocarbons is small in these cases, it is preferred that low temperature complex formation, favoring the production of complexes having a relatively high thiourea hydrocarbon ratio. be used.
  • The'thiourea process applies in a like manner to improving stocks and recycled feed in alkylation processes.
  • a mixture of alkylate and unreacted feed is produced .by passing a feed stockof oleflns and paramns through reactors containing catalysts such as concentrated cold sulfuric acid or hydrogen fluoride.
  • catalysts such as concentrated cold sulfuric acid or hydrogen fluoride.
  • the mixed product is fractionated to remove most of the alkylate, while the remainder, comprising feed constituents and a small amount of alkylate is recycled through the alkylator. Unless this remaining alkylate is removed the efliciency of the allrylation process is reduced.
  • the remainder of the latter may be removed as a thiourea complex.
  • This may be done in one of two ways: either by forming complexes of both isoparaflln feed stock and the alkylate and subsequently separating the isoparaflins for introduction back into the recycling line; or by adjusting reaction conditions so that the simple isoparaflins are left unchanged, while the alkylate forms a complex and can be separated from the remaining fractions by crystallization.
  • the thiourea process may be used to isolate the isoparafilns and naphthenes from straight run or processed gasoline.
  • the concentrate so obtained may be used as such or for blending purposes.
  • the rafllnate after removal of arcmatics, for example by solvent extraction, may be used as feed for isomerization, dehydrocyclization or other processes for converting normal paraffins to improved products.
  • the naphthene and isoparaflin fractions, isolated as thiourea complexes, may be used as feed stocks for hydro-' forming.
  • Triptane is outstanding in its ability to form crystalline complexes with thiourea. Hence, advantage may be taken of this in analysis for and recovery of trlptane from alkylates or other hydrocarbon mixtures.
  • Modifications of the complex are possible to produce special fractions, such as formation of the hydrochloride salts, acetate salts, etc.
  • a preferred method for such formations is to Drepare the complexes as described hereinbefore and subsequently treat the complex, preferably in solution, with dilute hydrochloric acid or acetic anhydrlde, in the presence of any necessary catalysts. For example, the presence of sodium acetate during the formation of the complex-acetate facilitates acetylation.
  • hydrocarbonthiourea complexes per se are useful for a number of purposes. They may be used for the fixation and storage of the more volatile hydrocarbons. They are useful in insecticides and fumigants. They are suitable for use in the preparation of pharmaceuticals and other chemical compounds.
  • Table III sample Mixture Thlourea Complex A 50% normal hcptanc, 50% isooctane isooctane.
  • B 959 normal lluptanc, triptane triptane, O 90% normal hcpiam, triptane; .l Do.
  • D 80% normal hcptanc triptane Do, 15.. 75% normal hcpumo, ',' ⁇ .2,3-d
  • F 50" normal licplanc, 505; cyclohexanc cyclohexane.
  • G 956,. normal hcplum', 5'2, cyclohexane
  • H 50% normal licplanc, 50% incthylcyclohexane mcthylcyclohexane.
  • I 50% ll, 2-(limclhylcyclollcxane, 50% 1, 4-dimethylcy- Predominantly l, 4-dimcthylcyclohexana cln lcxane.
  • J 50%1,4-dimcthylcyclohexane,50%ethylcyclohexane. Predominantly ethylcyclohexane.
  • EXAMPLE VI Twenty-five parts of isooctane and 60 parts of a 50% solution of thiourea in methylalcohol were mixed at 10 C. The crystalline thiourea-isooctane complex was filtered and washed with normal pentane, then subjected to dry distillation. The complex decomposed, isooctane being distilled while thiourea remained in the still.
  • EXAMPLE VII Forty parts of an untreated straight run petroleum fraction boiling between 415 F. and 660 F. was treated at 10 C. with 60 parts of a 50% solution of thiourea in methyl alcohol. The crystalline complex of thiourea and hydrocarbons, which formed rapidly, was filtered oil and washed with normal heptane. Water was added to the crystals and the mixture was warmed to about 80 C. The crystals coalesced to form an immiscible layer over the water. After decantation it was found that the upper layer was composed of a mixture of hydrocarbons, while the aqueous layer was a solution of thiourea.
  • composition of matter comprising a crystalline complex of triptane and thiourea.
  • composition of matter comprising a crystalline complex of cyclohexane and thiourea.
  • composition of matter comprising a crystalline complex of methylcyclopentane and thiourea.
  • composition of matter comprising a crystalline complex of a cycloparaflln hydrocarbon and thiourea.
  • cycloolefins and alkylated aromatic hydrocarbons having at least one isoparamn radical of at least 6 carbon atoms in the presence of water at a temperature below C. and isolating the complex so formed.
  • composition of matter comprising a crystalline complex of an isoparaflln hydrocarbon and thiourea.
  • composition or matter comprising a cry:- talline complex of iso-octane and thiourea.
  • composition of matter comprising a crystalline complex of 2,3-dimethylbutane and thiourea.

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US2569985A (en) * 1948-02-16 1951-10-02 Shell Dev Thiourea-ketone complexes
US2577202A (en) * 1949-09-30 1951-12-04 Process for separating organic
US2594481A (en) * 1948-09-30 1952-04-29 Standard Oil Co Separation of alcohols
US2599130A (en) * 1949-09-19 1952-06-03 Marathon Corp Laminated sheet material
US2604430A (en) * 1949-02-24 1952-07-22 Texas Co Continuous process for separation of waxlike constituents from oil
US2606140A (en) * 1948-12-30 1952-08-05 Texas Co Separation of wax constituents and the like from oil
US2606214A (en) * 1949-09-30 1952-08-05 Standard Oil Co Method of removing inhibitors for urea adduct formation
US2618664A (en) * 1950-07-29 1952-11-18 Texas Co Process for isolating phenolic compounds from mixtures thereof
US2618665A (en) * 1950-07-29 1952-11-18 Texas Co Process for isolating phenolic compounds from mixtures thereof
US2632002A (en) * 1953-03-17 Countercurkent sltjbb
US2635986A (en) * 1949-02-10 1953-04-21 Texas Co Continuous process for separation of waxlike constituents from oil
US2637681A (en) * 1948-12-09 1953-05-05 Texas Co Fractional separation of wax from a hydrocarbon mixture using an organic complexing agent and a solvent
US2640051A (en) * 1953-05-26 Process for the decomposition of
US2642422A (en) * 1953-06-16 Gorin
US2642378A (en) * 1949-09-13 1953-06-16 Socony Vacuum Oil Co Inc Separation of wax from residual lubricating oil
US2642379A (en) * 1949-09-13 1953-06-16 Socony Vacuum Oil Co Inc Separation of wax and asphalt from hydrocarbon oil
US2642424A (en) * 1953-06-16 Method of separating hydrocarbons
US2642423A (en) * 1953-06-16 Charge
US2653123A (en) * 1953-09-22 Continuous process for separation
US2653122A (en) * 1953-09-22 Fractional separation of oil with a complexing agent
US2653147A (en) * 1953-09-22 Separation process
US2658060A (en) * 1953-11-03 Process for centrifugal separation
US2658887A (en) * 1949-06-07 1953-11-10 Process for forming urea complexes
US2661317A (en) * 1949-03-17 1953-12-01 Texas Co Separation of wax constituents and the like from oil
US2663703A (en) * 1953-12-22 Purification of stkaight-chain
US2663671A (en) * 1953-12-22 Method of breaking a urea complex
US2666048A (en) * 1954-01-12 Separation of low molecular weight
US2672457A (en) * 1954-03-16 Pbocess for the decomposition of
US2676167A (en) * 1954-04-20 Separation process
US2676141A (en) * 1954-04-20 Process fok
US2681334A (en) * 1954-06-15 Formation of urea complexes with
US2681335A (en) * 1954-06-15 Gorin
US2681303A (en) * 1954-06-15 separation of hydrocarbons and hydrocarbon
US2681302A (en) * 1954-06-15 Separ
US2685578A (en) * 1954-08-03 Hydrocarbon separation process
US2689845A (en) * 1954-09-21 Sepakating organic compounds
US2695283A (en) * 1954-11-23 Method of forming urea and tfflourea
US2698321A (en) * 1954-12-28 Flash
US2700664A (en) * 1950-11-17 1955-01-25 Phillips Petroleum Co Separation of organic compounds by adduct formation
US2716113A (en) * 1955-08-23 Separation process
US2719145A (en) * 1955-09-27 Process for effecting complex
US2723220A (en) * 1950-04-10 1955-11-08 Phillips Petroleum Co Dewaxing of lubricating oil
US2731455A (en) * 1956-01-17 Pour point reduction of petroleum oil
US2731456A (en) * 1956-01-17 Sub-zone
US2731457A (en) * 1950-05-17 1956-01-17 Production and use of a urea suspension
US2732413A (en) * 1956-01-24 Process for the recovery of benzene by
US2735843A (en) * 1956-02-21 weedman
US2739144A (en) * 1956-03-20 Iio hsvm
US2744887A (en) * 1950-08-03 1956-05-08 Phillips Petroleum Co Decomposing urea adducts by countercurrently contacting the urea adduct with a hot gas, removing the urea fines and recycling the larger urea particles
US2758108A (en) * 1950-04-10 1956-08-07 Phillips Petroleum Co Preparation of adduct of urea or thiourea in the presence of an aqueous solution of monoethylamine
US2759917A (en) * 1956-08-21 Recovery of cyclohexane and methyl
US2759918A (en) * 1956-08-21 Gorin
US2759915A (en) * 1956-08-21 Gorin
US2766269A (en) * 1950-10-24 1956-10-09 British Petroleum Co Production of esters
US2773858A (en) * 1950-03-27 1956-12-11 Manuel H Gorin Method of preparing expanded urea
US2774752A (en) * 1956-12-18 Process for treating hydrocarbons with thiourea
US2779710A (en) * 1953-07-01 1957-01-29 Sonneborn Sons Inc L Process of upgrading petrolatum
US2798102A (en) * 1952-10-25 1957-07-02 Union Oil Co Method of decomposing werner complex clathrates
US2799623A (en) * 1953-07-16 1957-07-16 Ashland Oil Inc Process for separating waxes from oil
US2801993A (en) * 1953-08-11 1957-08-06 Rosenstein Ludwig Expanded thiourea
US2804451A (en) * 1957-08-27 Urea adducts of organic sulfur
US2814611A (en) * 1952-12-31 1957-11-26 British Petroleum Co Production of solid non-ionic surface active agents
US2834716A (en) * 1954-05-19 1958-05-13 Separation of hydrocarbons
US2849513A (en) * 1953-12-07 1958-08-26 Union Oil Co Separation of hydrocarbons by clathrate formation with werner complex compounds
US2855390A (en) * 1952-05-24 1958-10-07 champagnat ctau
US2872409A (en) * 1953-09-23 1959-02-03 Method of separating n-paraffins from hydrocarbons
US2889260A (en) * 1954-11-27 1959-06-02 Process for the dewaxing of oils
US2906744A (en) * 1956-03-15 1959-09-29 Standard Oil Co Insecticidal compositions
US3007896A (en) * 1952-09-17 1961-11-07 Metallgesellschaft Ag Polymerization of a poly-reactable compound in a canal former
US3071534A (en) * 1954-09-18 1963-01-01 Process and apparatus for separating paraffins
US3132084A (en) * 1960-09-23 1964-05-05 Texaco Inc Complex forming dewaxing composition and process

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DE856296C (de) * 1950-07-08 1952-11-20 Basf Ag Verfahren zum Zerlegen von organischen Stoffgemischen
DE1049032B (de) * 1955-04-29 1959-01-22 Oelwerke Julius Schindler G M Verfahren zum kontinuierlichen Entparaffinieren von Kohlenwasserstoffoelen mittels Harnstoffaddukten
DE1030491B (de) * 1956-03-31 1958-05-22 Scholven Chemie Ag Verfahren zur Trennung von Stoffgemischen mittels Harnstoff unter Verwendung eines Verduennungsmittels
CN109096034B (zh) * 2018-07-17 2021-09-03 天津大学 反应分离耦合分离正构烃与异构烃的工艺与装置

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US2221301A (en) * 1939-02-13 1940-11-12 Herman B Kipper Treatment of unsaturated hydrocarbon oils

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US2221301A (en) * 1939-02-13 1940-11-12 Herman B Kipper Treatment of unsaturated hydrocarbon oils

Cited By (73)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2689845A (en) * 1954-09-21 Sepakating organic compounds
US2632002A (en) * 1953-03-17 Countercurkent sltjbb
US2804451A (en) * 1957-08-27 Urea adducts of organic sulfur
US2774752A (en) * 1956-12-18 Process for treating hydrocarbons with thiourea
US2759915A (en) * 1956-08-21 Gorin
US2759918A (en) * 1956-08-21 Gorin
US2759917A (en) * 1956-08-21 Recovery of cyclohexane and methyl
US2739144A (en) * 1956-03-20 Iio hsvm
US2735843A (en) * 1956-02-21 weedman
US2698321A (en) * 1954-12-28 Flash
US2732413A (en) * 1956-01-24 Process for the recovery of benzene by
US2731456A (en) * 1956-01-17 Sub-zone
US2640051A (en) * 1953-05-26 Process for the decomposition of
US2642422A (en) * 1953-06-16 Gorin
US2731455A (en) * 1956-01-17 Pour point reduction of petroleum oil
US2719145A (en) * 1955-09-27 Process for effecting complex
US2642424A (en) * 1953-06-16 Method of separating hydrocarbons
US2642423A (en) * 1953-06-16 Charge
US2653123A (en) * 1953-09-22 Continuous process for separation
US2653122A (en) * 1953-09-22 Fractional separation of oil with a complexing agent
US2653147A (en) * 1953-09-22 Separation process
US2658060A (en) * 1953-11-03 Process for centrifugal separation
US2716113A (en) * 1955-08-23 Separation process
US2695283A (en) * 1954-11-23 Method of forming urea and tfflourea
US2663703A (en) * 1953-12-22 Purification of stkaight-chain
US2663671A (en) * 1953-12-22 Method of breaking a urea complex
US2685578A (en) * 1954-08-03 Hydrocarbon separation process
US2666048A (en) * 1954-01-12 Separation of low molecular weight
US2672457A (en) * 1954-03-16 Pbocess for the decomposition of
US2676167A (en) * 1954-04-20 Separation process
US2676141A (en) * 1954-04-20 Process fok
US2681334A (en) * 1954-06-15 Formation of urea complexes with
US2681335A (en) * 1954-06-15 Gorin
US2681303A (en) * 1954-06-15 separation of hydrocarbons and hydrocarbon
US2681302A (en) * 1954-06-15 Separ
US2569985A (en) * 1948-02-16 1951-10-02 Shell Dev Thiourea-ketone complexes
US2594481A (en) * 1948-09-30 1952-04-29 Standard Oil Co Separation of alcohols
US2637681A (en) * 1948-12-09 1953-05-05 Texas Co Fractional separation of wax from a hydrocarbon mixture using an organic complexing agent and a solvent
US2606140A (en) * 1948-12-30 1952-08-05 Texas Co Separation of wax constituents and the like from oil
US2635986A (en) * 1949-02-10 1953-04-21 Texas Co Continuous process for separation of waxlike constituents from oil
US2604430A (en) * 1949-02-24 1952-07-22 Texas Co Continuous process for separation of waxlike constituents from oil
US2661317A (en) * 1949-03-17 1953-12-01 Texas Co Separation of wax constituents and the like from oil
US2658887A (en) * 1949-06-07 1953-11-10 Process for forming urea complexes
US2666020A (en) * 1949-06-07 1954-01-12 Sepaeation of wax-like constituents
US2642379A (en) * 1949-09-13 1953-06-16 Socony Vacuum Oil Co Inc Separation of wax and asphalt from hydrocarbon oil
US2642378A (en) * 1949-09-13 1953-06-16 Socony Vacuum Oil Co Inc Separation of wax from residual lubricating oil
US2599130A (en) * 1949-09-19 1952-06-03 Marathon Corp Laminated sheet material
US2577202A (en) * 1949-09-30 1951-12-04 Process for separating organic
US2606214A (en) * 1949-09-30 1952-08-05 Standard Oil Co Method of removing inhibitors for urea adduct formation
US2773858A (en) * 1950-03-27 1956-12-11 Manuel H Gorin Method of preparing expanded urea
US2758108A (en) * 1950-04-10 1956-08-07 Phillips Petroleum Co Preparation of adduct of urea or thiourea in the presence of an aqueous solution of monoethylamine
US2723220A (en) * 1950-04-10 1955-11-08 Phillips Petroleum Co Dewaxing of lubricating oil
US2731457A (en) * 1950-05-17 1956-01-17 Production and use of a urea suspension
US2618664A (en) * 1950-07-29 1952-11-18 Texas Co Process for isolating phenolic compounds from mixtures thereof
US2618665A (en) * 1950-07-29 1952-11-18 Texas Co Process for isolating phenolic compounds from mixtures thereof
US2744887A (en) * 1950-08-03 1956-05-08 Phillips Petroleum Co Decomposing urea adducts by countercurrently contacting the urea adduct with a hot gas, removing the urea fines and recycling the larger urea particles
US2766269A (en) * 1950-10-24 1956-10-09 British Petroleum Co Production of esters
US2700664A (en) * 1950-11-17 1955-01-25 Phillips Petroleum Co Separation of organic compounds by adduct formation
US2855390A (en) * 1952-05-24 1958-10-07 champagnat ctau
US3007896A (en) * 1952-09-17 1961-11-07 Metallgesellschaft Ag Polymerization of a poly-reactable compound in a canal former
US2798102A (en) * 1952-10-25 1957-07-02 Union Oil Co Method of decomposing werner complex clathrates
US2814611A (en) * 1952-12-31 1957-11-26 British Petroleum Co Production of solid non-ionic surface active agents
US2824091A (en) * 1952-12-31 1958-02-18 British Petroleum Co Production of solid non-ionic surface active agents
US2779710A (en) * 1953-07-01 1957-01-29 Sonneborn Sons Inc L Process of upgrading petrolatum
US2799623A (en) * 1953-07-16 1957-07-16 Ashland Oil Inc Process for separating waxes from oil
US2801993A (en) * 1953-08-11 1957-08-06 Rosenstein Ludwig Expanded thiourea
US2872409A (en) * 1953-09-23 1959-02-03 Method of separating n-paraffins from hydrocarbons
US2849513A (en) * 1953-12-07 1958-08-26 Union Oil Co Separation of hydrocarbons by clathrate formation with werner complex compounds
US2834716A (en) * 1954-05-19 1958-05-13 Separation of hydrocarbons
US3071534A (en) * 1954-09-18 1963-01-01 Process and apparatus for separating paraffins
US2889260A (en) * 1954-11-27 1959-06-02 Process for the dewaxing of oils
US2906744A (en) * 1956-03-15 1959-09-29 Standard Oil Co Insecticidal compositions
US3132084A (en) * 1960-09-23 1964-05-05 Texaco Inc Complex forming dewaxing composition and process

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