Process for treating hydrocarbons

A process for chemically modifying at least one component of a hydrocarbon-based material comprising: contacting the hydrocarbon-based material with at least one metal component selected from the group consisting of vanadium components in which vanadium is present in the 5+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbon-based material, iron components in which iron is present in the 3+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbon-based material, managanese components in which manganese is present in the 3+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbon-based material and mixtures thereof, and at least one oxygen transfer agent in an amount effective to do at least one of the following: maintain at least partially the promoting activity of the metal component; produce at least a portion of metal component; and oxidize at least a portion of the component of the hydrocarbon-based material, the contacting occurring at conditions effective to chemically modify the component of the hydrocarbon-based material. This application is a continuation of application Ser. No. 225,732, filed July 29, 1988, now abandoned, which in turn is a continuation-in-part of application 931,246, filed Nov. 17, 1986, now abandoned.

BACKGROUND OF THE INVENTION 
This invention relates to a process for treating hydrocarbon-based 
materials, such as petroleum and petroleum fractions. More particularly, 
the invention relates to processes wherein one or more components of such 
materials are oxidized and/or otherwise chemically modified. 
Petroleum and petroleum fractions are important fuels, and large amounts 
are burned. One of the principal drawbacks of the use of these materials 
as fuel is that many such materials contain amounts of sulfur and other 
components which generate unacceptable amounts of pollutants, e.g., sulfur 
oxides, on burning. 
It would be clearly be advantageous to provide a process to desulfurize 
such fuels and/or otherwise treat such fuels to reduce the above-noted 
pollution concerns. For example, other than desulfurization, petroleum and 
petroleum fractions may be cracked to lower boiling components which are 
often more effectively combusted and result in reduced emission of 
potential pollutants. Also, petroleum and petroleum fractions may be 
demetallized and/or otherwise treated so that the resulting material is 
more amenable to being economically processed, e.g., upgraded to higher 
quality products. 
SUMMARY OF THE INVENTION 
A new process for chemically modifying, preferably chemically reacting or 
chemically converting, at least one component of a hydrocarbon-based 
material has been discovered. This process provides an effective, 
convenient and economical approach to chemically modifying, more 
preferably oxidizing, cracking, demetallizing, forming surfactants from, 
or altering the viscosity of or the like, one or more components of a 
hydrocarbon-based material, preferably petroleum. 
One broad aspect of the present invention comprises contacting the 
hydrocarbon-based material with at least one oxygen transfer agent, 
preferably a reducible manganese component, and at least one vanadium 
component and/or at least one iron component and/or manganese component at 
conditions effective to chemically modify, preferably oxidize, crack, 
demetallize, form surfactants from, or alter the viscosity or the like, at 
least one component of the hydrocarbon based material. Vanadium is present 
in the 4+and/or 5+oxidation states, preferably in the 5+oxidation state, 
in an amount effective to promote the chemical modification of the 
component. Iron is present in an amount in the 3+oxidation state effective 
to promote the chemical modification of the component. Manganese is 
present in an amount in the 3+oxidation state effective to promote the 
chemical modification of the component. The vanadium component and/or the 
iron component and/or manganese component is preferably substantially 
soluble at the conditions of use. The oxygen transfer agent is present 
during the contacting in an amount effective to do at least one of the 
following: maintain at least partially the promoting activity of the 
vanadium component and/or iron component; produce at least a portion of 
the vanadium component and/or iron component and/or manganese component; 
and oxidize at least a portion of the component of the hydrocarbon-based 
material. 
In another broad aspect, the present process comprises contacting a 
hydrocarbon-based material with at least one petroleum hydrocarbon 
material. manganese (3+) cyclable ligand complex in which manganese is 
present in the 3+oxidation state in an amount effective to promote the 
chemical modification of at least one component of the hydrocarbon-based 
material, preferably with an oxidant, at conditions effective to 
chemically modify one or more of such components. 
The present process advantageously results in the chemical modification of 
one or more components of the hydrocarbon-based material. Such chemical 
modification, as described herein, of such component or components often 
results in enhanced value of the resulting hydrocarbon-based product 
and/or produces a treated hydrocarbon-based material which can be further 
processed, e.g., to yield high quality products, more effectively than the 
original or untreated hydrocarbon material. The present invention can 
provide a cost effective approach to providing high quality and high value 
hydrocarbon- based products. 
DETAILED DESCRIPTION OF THE INVENTION 
The present process is effective for treating hydrocarbon-based materials. 
Any suitable hydrocarbon-based material may be treated in the present 
process. Such materials include organic sulfur, in particular, 
non-thiophenic sulfur. Such hydrocarbon-based materials may also include 
one or more metallic or metal-containing components which can beneficially 
be removed, e.g., to render the resulting demetallized hydrocarbonbased 
material more amenable to further processing. Examples of 
hydrocarbon-based materials which may be processed in accordance with the 
present invention include whole petroleums (crude oils including topped 
crude oils), petroleum residua (both vacuum and, preferably, atmospheric 
residua), gas oils, middle distillates, naphthas, and the like and 
mixtures thereof. The present process is particularly applicable to heavy 
feedstocks, such as those selected from the group consisting of whole 
petroleums, petroleum residua and mixtures thereof. Because the present 
process is particularly effective in removing non-thiophenic sulfur, the 
material used is preferably not subjected to conditions prior to the 
contacting which are effective to increase the amount of thiophenic sulfur 
present in the material. Such conditions, which often act to rearrange the 
sulfur-containing components in the material to thiophenic 
sulfur-containing components, may include temperatures of at least about 
800.degree. F. or at least about 1000.degree.F. or more. 
In one embodiment of the invention, the process comprises: contacting the 
hydrocarbon-based material with at least one of the following: (1) at 
least one of certain vanadium and/or iron and/or manganese components 
present in an amount effective to promote the chemical modification of at 
least one component of the hydrocarbon-based material and at least one 
oxygen transfer agent; and/or (2) at least one manganese (3+) ligand 
complex in an amount effective to promote such chemical modification, and 
preferably at least one oxidant. A hydrocarbon-based product having at 
least one improved property relative to the hydrocarbon-based material is 
recovered. 
The present process has been found to provide for the chemical modification 
of hydrocarbon-based materials, e.g., crude petroleum, to provide high 
quality and high value products, preferably in high yields. For example, 
the vanadium components, iron components, manganese components, oxygen 
transfer agents, and oxidants, e.g., as described herein, which may be 
employed are relatively inexpensive, readily available and/or easy to 
produce. 
The term "chemical modification" as used herein refers to a change in one 
or more of the components of the hydrocarbonbased material, which change 
preferably results from the chemical reaction, more preferably oxidation, 
cracking or demetallization, of one or more of such components. In certain 
instances, no specific chemical reaction can be pointed to account for the 
change in the component or components. Also, the chemical modification may 
occur with regard to the carbon and/or hydrogen portions of the 
hydrocarbon-based material and /or to the other portions, e.g.. such as 
contained sulfur, nitrogen, oxygen, metals or the like, of such 
hydrocarbon-based materials. 
One embodiment the present process involves contacting a hydrocarbon-based 
material with at least one metal component selected from vanadium 
components, iron components, manganese components and mixtures thereof, 
and at least one oxygen transfer agent. The vanadium component is such 
that vanadium is present in the 4+and/or 5+oxidation states, preferably in 
the 5+oxidation state, in an amount effective to promote the chemical 
modification of at least one component of the hydrocarbon-based material. 
The iron component is such that the iron is present in the 3+oxidation 
state in an amount effective to promote the chemical modification of at 
least one component of the hydrocarbon-based material. The manganese 
component is such that the manganese is present, preferably in the 
3+oxidation state, in an amount effective to promote the chemical 
modification of at least one component of the hydrocarbon-based material. 
The oxygen transfer agent is present in an amount effective to do at least 
one of the following: maintain at least partially the promoting activity 
of the metal component; produce at least a portion of the metal component; 
and oxidize at least a portion of the component of the hydrocarbon-based 
material. 
Such contacting may occur over a wide pH range, e.g., about 1 or less to 
about 13 or more, preferably at a slightly acidic pH, i.e., a pH no lower 
than about 6, or at an alkaline pH. If vanadium is present, the contacting 
is more preferably conducted at a pH in the range of about 6 to about 13, 
while if the iron component is present, the pH is more preferably about 
6.5 to about 9.5. If manganese 3+is present, the pH is more preferably 
about 7.5 to about 10.5. These more preferred pH ranges are particularly 
useful when it is desired to maintain the metal component substantially 
soluble, e.g., in the liquid medium used to carry the metal component or 
components and/or the oxygen transfer agent to the contacting, at the 
contacting conditions. 
The vanadium component or components useful in the present invention may be 
chosen from any such components which function as described herein. 
Examples of useful components include vanadium pentoxide, soluble 
vanadates and oxyanion derivatives thereof, complexes of vanadium with 
ligands and other compounds in which vanadium is present in the 
5+oxidation state. Preferably, the vanadium component or components are 
capable of being reduced to a lower oxidation state, e.g., to oxidize at 
least one component of the hydrocarbon-based material and of being 
oxidized to the 5+oxidation state by the oxygen transfer agent at the 
contacting conditions. In one embodiment, the vanadium component or 
components are preferably substantially soluble in the above-noted liquid 
medium at the contacting conditions. A particularly useful embodiment 
involves one or more vanadium (5+) complexes with ligands, which 
complexes, as well as the corresponding reduced forms during the time 
prior to reoxidation, are more preferably substantially soluble in the 
liquid medium at the contacting conditions. 
The iron component or components useful in the present invention may be 
chosen from any such components which function as described herein. 
Preferably, the iron component or components are capable of being reduced 
to a lower oxidation state, e.g., to oxidize at least one component of the 
hydrocarbon-based material, and of being oxidized to the 3+oxidation state 
by the oxygen transfer agent at the contacting conditions. In certain 
embodiments, the iron component or components are preferably substantially 
soluble in the liquid medium at contacting conditions. A particularly 
useful embodiment involves iron (3+) complexes with ligands, which 
complexes, as well as the corresponding reduced forms during the time 
prior to reoxidation, are more preferably substantially soluble in the 
liquid medium at the contacting conditions. 
The manganese component or components useful in the present invention may 
be chosen from any such components which function as described herein. 
Preferably, the manganese component or components are capable of being 
reduced to a lower oxidation state, e.g., to oxidize at least one 
component of the hydrocarbon-based material, and of being oxidized to the 
3+ oxidation state by the oxygen transfer agent at the contacting 
conditions. In certain embodiments, the manganese components or components 
are preferably substantially soluble in the liquid medium at contacting 
conditions. A particularly useful embodiment involves manganese (3+) 
complexes with ligands, which complexes, as well as the corresponding 
reduced forms during the time prior to reoxidation, are more preferably 
substantially soluble in the liquid medium at the contacting conditions. 
The oxygen transfer agent or agents may be chosen from any suitable 
materials capable of functioning as described herein. In certain 
instances, non-metal containing materials, such as molecular oxygen, may 
be employed. The oxygen transfer agent preferably includes at least one 
metal species which is capable of being reduced, e.g., to oxidize the 
vanadium or iron components, at the conditions of the present contacting. 
More preferably, the reduced oxygen transfer agent is also capable of 
being oxidized to the oxygen transfer agent at the present contacting 
conditions, although one time (e.g., once through) use of the oxygen 
transfer agent or reoxidation of the reduced oxygen transfer agent to the 
oxygen transfer agent external or separately from the present contacting 
can also be practiced. The oxygen transfer agent preferably includes at 
least one oxygen species. In one particularly useful embodiment, the 
oxygen transfer agent comprises a reducible, redox cyclable manganese 
component. 
By "reducible manganese component" or "RMC" is meant a manganese component 
which is capable of being chemically reduced at the conditions of the 
present contacting. Preferably, the RMC includes manganese, more 
preferably a major amount of manganese, in at least one of the 3+and 
4+oxidation states. Particularly useful RMCs include manganese dioxide, 
i.e., Mn0.sub.2, soluble manganese in the (3+) oxidation state and 
mixtures thereof. The RMC can be provided from any suitable source, such 
as manganese halide and the like. The manganese component originally 
present may be subjected to oxidation, e.g., by contact with air and/or 
other manganese oxidant in the presence of base, in order to obtain and/or 
regenerate the presently useful RMC. The amount of RMC employed may vary 
over a wide range depending on, for example, the specific RMC being 
employed, what, if any, oxidant is being used, the specific 
hydrocarbon-based material being treated, and the type and degree of 
chemical modification desired. Preferably, the amount of RMC included in 
the present contacting step is sufficient to maintain the desired amount 
of vanadium in the 5+oxidation state or the desired amount of iron in the 
3+oxidation state during the contacting. Substantial excesses of RMC 
should be avoided since such excesses may result in material separation 
and handling problems, and may even result in reduced recovery of 
hydrocarbon-based products. In one embodiment, the reducible manganese 
component or components, are substantially soluble in the liquid medium at 
the contacting conditions. Such substantially soluble manganese components 
are preferably selected from manganese (3+) ligand complexes, as described 
herein. 
The contacting is preferably conducted in the present of at least one 
additional oxidant, preferably other than the oxygen transfer agent. The 
oxidant is present in an amount effective to do at least one of the 
following: maintain at least partially the promoting activity of the 
vanadium and/or iron and/or manganese component and/or the manganese (3+) 
complex; produce at least a portion of the oxygen transfer agent; and 
oxidize at least one component of the hydrocarbon-based material. Such 
oxidant is preferably selected so as to produce, or at least maintain, an 
effective amount of the oxygen transfer agent during the contacting. The 
oxidant or oxidants may be present during the contacting step and/or 
during a separate step to form and/or regenerate the vanadium and/or iron 
and/or manganese component, the manganese (3+) complex and/or the oxygen 
transfer agent. 
Any suitable oxidant capable of performing one or more of the above-noted 
functions may be employed. The oxidant is preferably selected from the 
group consisting of molecular oxygen (e.g., in the form of air, dilute or 
enriched air, or other mixtures with nitrogen or carbon dioxide) singlet 
oxygen, ozone, inorganic oxidant components containing oxygen and at least 
one metal, preferably manganese, and mixtures thereof. More preferably, 
the oxidant is selected from the group consisting of molecular oxygen, 
oxidant components containing oxygen and at least one metal and mixtures 
thereof, especially molecular oxygen. A particularly useful oxidant 
comprises a mixture of molecular oxygen with carbon dioxide in an amount 
effective to promote the molecular oxygen access to and contact with the 
hydrocarbons. The use of carbon dioxide has been found to enhance the 
chemical modification, of the component or components of the 
hydrocarbon-based material. Although carbon dioxide may be used alone, 
i.e., substantially without an oxidant, it is preferably employed with an 
oxidant, and more preferably with molecular oxygen. When used with 
molecular oxygen, the carbon dioxide is preferably present in an amount in 
the range of about 0.1 to about 1000 moles of carbon dioxide per mole of 
molecular oxygen. Care should be exercised to avoid using carbon dioxide 
in amounts which substantially detrimentally affect the pH of the 
contacting liquid medium, reduce the pH of the liquid medium below the 
desired level for solubility useful for metal component hydrocarbon 
modification, e.g.. oxidation, activity. 
Large excesses of the oxidant should be avoided so that the 
hydrocarbon-based material is not unduly oxidized and destroyed. The 
amount of oxidant employed is preferably in the range of about 5to about 
150of that needed to oxidize by one oxidation state the total amount of 
sulfur present in the hydrocarbon-based material fed to the present 
contacting step, or, in certain instances, of that needed to oxidize by 
one oxidation state the total amount of vanadium and/or iron and/or 
manganese component, and/or manganese 3+ligand complex and/or oxygen 
transfer agent fed to the present contacting step. 
Without wishing to be limited to any particular theory of operation, an 
illustrative example of the vanadium/oxygen transfer agent/oxidant 
embodiment of the present invention is believed to function as follows. 
The vanadium (5+) component acts directly on the component of the 
hydrocarbon-based material to be chemically, preferably oxidatively, 
modified. This interaction results in the vanadium species being reduced 
in oxidation state. The oxygen transfer agent, however, acts to oxidize 
this "reduced" vanadium to the 5+oxidation state, and the oxidant oxidizes 
the resulting reduced oxygen transfer agent to the oxygen transfer agent. 
Such oxygen transfer agents, and in particular reducible manganese 
components, have been found to be effective in oxidizing the vanadium 
component to the 5+oxidation state, while various other oxidants, such as 
molecular oxygen, are substantially ineffective in oxidizing the reduced 
vanadium component or components. However, molecular oxygen is effective 
to oxidize a reduced redox cyclable manganese component to a reducible 
manganese component and a reduced redox cyclable iron complex to an iron 
(3+) complex. 
The vanadium (5+) complexes, iron (3+) complexes and manganese (3+) 
complexes useful in the present invention involve one or more ligands. 
The presently useful metal complexes are preferably not fully complexed, 
for example, partial ligand complexes, i.e., not fully complexed at a 
ratio of ligand to metal which substantially reduces the redox cycling 
activity of the ligand complexes. This feature i.e., active redox cycling 
complexes, apparently facilitate the ability of the metal species to 
rapidly cycle between oxidation states and/or to promote the desired 
chemical modification, preferably oxidation, of the component of the 
hydrocarbons in the reservoir. With vanadium complexes, the mol ratio of 
vanadium to ligand is more preferably about 1 to about 3, still more 
preferably to about 2, with iron complexes the mol ratio of iron to ligand 
is more preferably about 1 to about 3, more preferably to about 2, and 
with manganese complexes the mol ratio of manganese to ligand is more 
preferably about 1 to about 2.0, still more preferably to about 1.5. 
Any suitable ligand system may be employed. The ligands are preferably 
derived from the group consisting of compounds containing acetylacetonate 
functionality, carboxylic acid functionality (more preferably containing 
up to about 15 carbon atoms per molecule), poly, more preferably three, 
carboxylic acid functionalities, substituted carboxylic acid functionality 
(more preferably containing up to about 15 carbon atoms per molecule) 
poly, more preferably three, substituted carboxylic acid functionalities, 
polyoxyanious more preferably polyphosphate for example tripolyphosphate 
and mixtures thereof. Particularly useful ligand systems are derived from 
the group consisting of compounds containing acetylacetonate 
functionality, citric acid functionality, tartaric acid functionality, 
nitrilotriacetic acid functionality and mixtures thereof and their partial 
salts, and partial esters and substituted / derivatives thereof. 
Particularly preferred species are citric acid, tartaric acid and 
nitrilotriacetic acid and their partial salts and esters thereof as 
illustrated above. 
Further examples of iron (3+) complexes useful in the present invention 
include iron complexes with polyfunctional amines, for example, 
ethylenediamine, propylene diamine, ethanol amine, glycine and asparagine 
and salts thereof; phosphonic acids and phosphonic acid salts, for 
example, ethane-1-hydroxy-l, 1-disphosphonic acid; pyridine and 
substituted, chelating pyridine, derivatives, for example, 1, 
10-phenanthroline, 2, 2'-bipyridyl, glyoxine and salicylaldehyde 
derivatives; aguo; and CN.sup.-. Among the particularly preferred iron 
complexing agents for use in the present invention are those selected from 
the group consisting of substituted, chelating derivatives of pyridine, 
aquo, CN.sup.- and mixtures thereof. 
Especially suitable salt forms of ligands are the potassium, sodium and 
ammonium salts. Mixtures of ligands can be employed. 
The specific amount of vanadium, iron and/or manganese component, oxygen 
transfer agent, and/or oxidant used to contact the hydrocarbon-based 
material is not narrowly critical to the present invention. However, such 
amount or amounts should be sufficient to perform the function or 
functions as described herein. The amount or amounts of one or more of 
these materials to be used depends on many factors, for example, the 
specific hydrocarbon-based material to be treated, and the type and degree 
of chemical modification desired. In certain applications, the amount of 
each of the vanadium, iron and/or manganese components and the reducible 
manganese component is in the range of about 0.005to about 1% by weight 
(calculated as elemental metal) of the liquid medium. In the event such 
materials are substantially soluble in the liquid medium, each of them is 
preferably present in the liquid medium in an amount in the range of about 
0.005% to about 0.5% by weight (calculated as elemental metal). 
Any suitable liquid medium may be employed. Because of cost and 
availability considerations, it is preferred that the liquid medium be an 
aqueous liquid medium. The liquid medium may also include one or more 
components, e.g., basic materials, such as lime, sodium hydroxide, sodium 
orthosilicate, sodium carbonate and/or sodium bicarbonate, useful for 
controlling the pH of the liquid medium and/or for chemically reacting 
with one or more components of the hydrocarbon-based material. 
The present contacting preferably takes place in the presence of an aqueous 
liquid medium, more preferably a slightly acidic or alkaline aqueous 
liquid medium. Any suitable aqueous liquid medium or composition may be 
employed in the present contacting step. The pH of the composition 
preferably is slightly acidic or alkaline and may vary depending, for 
example, on the specific hydrocarbon-based material being treated, and the 
make-up of the contacting composition. More preferably, when vanadium is 
employed, the pH of the aqueous liquid medium is in the range of about 6 
to about 13. When iron 3+is present, it is more preferred that the pH be 
in the range of about 6.5 to about 9.5, and when manganese 3+is present it 
is more preferred that the pH be in the range of about 7.5 to about 10.5. 
The pH of the aqueous liquid medium may be adjusted or maintained during 
the contacting step, for example, by adding one or more basic components 
to the aqueous liquid medium. Any suitable basic component or combination 
of such components may be included in, or added to, this medium to provide 
the desired basicity. For example, basic alkali metal and alkaline earth 
metal components, e.g., hydroxides, silicates, carbonates and 
bicarbonates, mixtures thereof and the like may be employed. Because of 
cost, availability and performance considerations, lime, sodium hydroxide, 
sodium carbonate, and mixtures thereof are preferred. 
The aqueous liquid medium comprises water, preferably a major amount of 
water. This medium is preferably substantially free of ions and other 
entities which have a substantial detrimental effect on the present 
process. Quantity and concentration of the liquid aqueous medium may be 
selected in accordance with the requirements of any given 
hydrocarbon-based material to the treated and as may be found advantageous 
for any given mode of applying the process in practice. 
The present contacting step preferably takes place at temperatures of less 
than about 300.degree. C., more preferably at temperatures in the range of 
about 20.degree. C. to about 200.degree. C. The contacting pressure and 
contacting time may vary over wide ranges and are not narrowly critical to 
the present invention. Pressures in the range of about 5 psia or less to 
about 1000 psia or more may be employed. Satisfactory results are achieved 
at pressures in the range of about atmospheric to about 100 psia. and are 
preferred to minimize equipment requirements and costs. Contacting times 
may vary depending, for example, on the specific hydrocarbon-based 
material being treated, the specific metalcontaining and other, if any, 
components present during the contacting, and the type and degree of 
chemical modification desired. Contact times in the range of about 5 
minutes or less to about 24 hours or more may be used. In certain 
embodiments, the contact time is preferably in the range of about 20 
minutes to about 6 hours, more preferably about 0.5 hours to about 3 
hours. During the contacting, agitation can be advantageously employed to 
enhance contacting. Mechanical mixers can be employed. Since the 
contacting can occur at ambient or moderately elevated temperatures, e.g., 
about 100.degree. C. or less, processing can take place in a pipeline, or 
other transportation or storage ( e.g., storage tank) system in which the 
residence time of the hydrocarbon-based material is often measured in 
days, weeks or even months. 
The contacting step may be carried out in any conventional manner, e.g., 
batchwise, semi-batchwise or continuously. Conventional equipment, such as 
stirred tanks, agitated or stirred autoclaves and the like, may be 
employed in performing the contacting step. 
After the contacting step, the treated hydrocarbonbased material is 
recovered. For example, the treated hydrocarbon-based material may be 
separated, e.g., by settling, centrifugation and the like, from the liquid 
medium. In addition, other techniques, such as distillation, filtration 
and the like, can be employed to provide one or more refined 
hydrocarbon-based materials which can be used as is or can be subjected to 
further processing, e.g., catalytic processing, to produce even higher 
quality hydrocarbon-based products. 
The following non-limiting examples illustrate certain of the advantages of 
the present invention.

EXAMPLES 1 TO 6 
A quantity of heavy Alaskan North Slope crude oil was selected from bench 
scale testing. 
Each experiment, including control Example 1, employed 50 ml of this crude 
oil (except Example 2, as noted below), 160 ml of an aqueous fraction and 
80g of sand, in order to better approximate subterranean reservoir 
conditions. Each of the systems was agitated by a propeller stirrer in a 
tall and narrow qlass container suspended in a water bath maintained at 
50.degree. C. 16 drops of a commercially available emulsifier was added to 
each system to aid in oil/water contacting. This emulsifier did not form 
any type of permanent emulsion. The conditions and results of each of 
these experiments are summarized as follows. EXAMPLE 1 (Control) 
Conditions: 160 ml of pH 9-10 aqueous solution; 50 ml of crude oil; 80 g of 
sand; 50.degree.C.; 3 days stirring. 
Results: Upon termination of stirring, the oil/water layers separated 
within 30 seconds to one minute. Some solid (sand) remained in the water. 
However, no visible effect was apparent on the crude oil fraction. 
EXAMPLE 2 
Conditions: 160 ml of pH 6.5 solution; 40 ml of crude oil; 80g of sand; 4g 
of MnO.sub.2; 3.2g of NaCl; 0.8g of NH.sub.4 Cl; 30.degree.C.; slow air 
bubbling; 3 days stirring. 
Results: Upon termination of stirring, there were no visible effects on the 
oil with this "MnO.sub.2 only" system. Very fine MnO.sub.2 particles were 
slow to settle, and some particles may have remained in the oil layer. 
Water/oil separation was very rapid, i.e., in a matter of minutes, with no 
differences from the control experiment (Example 1). 
EXAMPLE 3 
Conditions The aqueous fraction included 0.5% by weight of vanadium, as 
vanadium citrate (1.5 mol citrate:1 mol vanadium); 160 ml of pH 12 aqueous 
fraction; 7.4g of MnO.sub.2 ; 50 ml of crude oil; 80g sand; 50.degree.C.; 
3 days stirring. 
Results: Upon termination of stirring, an emulsion formed. The oil/water 
layers separated in 15-30 minutes, with small amounts of solid (sand, 
MnO.sub.2) remaining in the oil layer. 
EXAMPLE 4 Conditions: Same as Example 3, except that aqueous fraction also 
included 0.3% by weight of manganese, as manganese citrate (1.33 mol 
citrate:1 mol manganese), and the pH was reduced to 9. 
Results: Upon termination of stirring, an emulsion formed. The oil/water 
layers separated in 1 to 1.5 hours, with small amounts of solid (sand, 
MnO.sub.2) remaining in the oil layer. The aqueous layer was brown in 
color indicative of Mn.sub..sup.3 +(citrate). There appeared to have been 
more emulsion formation that was apparent in Example 3. 
EXAMPLE 5 
Conditions Same as Example 4, except that air was introduced via very slow 
bubbling 
(one bubble every 3-5 seconds), and this experiment was run for 7 days. 
Results: Upon termination of stirring, an emulsion formed. The oil/water 
layers separated in 1.5 to 2 hours, with small amounts of solid (sand, 
MnO.sub.2 remaining in the oil layer. After separation, the oil layer 
appeared to be larger than it was originally, indicating that some type of 
permanent emulsion had been formed. The formation of oil emulsions makes 
hydrocarbons in subterranean reservoirs more susceptible to being 
recovered. Without wishing to be limited to any particular theory of 
operation, the small amount of air introduced in this run may have been 
beneficial in keeping the manganese in the 3+oxidation state, which 
manganese 3+it is believed was able to regenerate vanadium 5+(citrate) 
without any involvement from the MnO.sub.2. 
EXAMPLE 6 
Conditions: Same as Example 5, except that the experiment was run for 3 
days. 
Results: After termination of stirring, an emulsion formed. The oil/water 
layers separated in 1.5 to 2 hours, with some solid (sand, MnO.sub.2) 
remaining in the oil layer. As in Example 5, the oil layer appeared to 
have the characteristics of some type of permanent emulsion. 
These examples show that the combination of vanadium and manganese, 
particularly such metals partially complexed with ands, an oxygen transfer 
agent such as MnO.sub.2, and an oxidant such as air, is effective to 
provide chemical modification of petroleum. Note that Examples 1 and 2, 
with none of the presently useful materials, showed little or no effect on 
the crude oil. 
While this invention has been described with respect to various specific 
examples and embodiments, it is to be understood that the invention is not 
limited thereto and that it can be variously practiced within the scope of 
the following claims.