close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2405872

код для вставки
2,45,872
Patented Aug. 13, 1946
UNITED STTES PATENT OFFICE
2,405,872
METHOD FOR REMOVING WEAKLY ACIDIC
SULPHUR COMPOUNDS FROM HYDRO
CARBON OIL
George W. Ayers, Chicago, and Daniel M. Barton,
Elmwood Park, 111., assignors to The Pure Oil
Company, Chicago, Ill., a corporation of Ohio
No Drawing. Application June 21, 1943,
Serial No. 491,668
8 Claims.
(01. 196—30)
2
1
a method for removing mercaptans from petrole
um distillates.
for removing weakly acidic bodies from water
A further object of the invention is to provide
immiscible organic fluids and is more particularly
a method for removing from high-boiling tar
concerned. with a method and reagent for re
acids, constituents which are objectionable when
moving mercaptans from petroleum oils,
tar acids are used as solubility promoters in al
In Patent No, 2,316,966 there is disclosed and
kali solutions to remove weakly acidic bodies such
claimed a method for removing acidic bodies from
as mercaptans from hydrocarbon or other sub
water-immiscible ?uids by contacting such fluids
stantially neutral water-immisible ?uids.
with aqueous alkali solutions containing the reac
A still further object of the invention is to
tion product of an alkali and high-boiling tar 10
provide an improved solubility promoter for use
We have found that high-boiling acids
' acids.
in extracting weakly acidic bodies from organic
may cause difficulties when used in the extraction
water-immiscible ?uids.
of mercaptans from gasoline and other petroleum
Other objects of the invention will appear from
distillates. These tar acids contain substances
which impart to the gasoline or other oil which 15 the following description:
In the low-temperature, by-product, destruc~
is treated therewith, objectionable color and
tive distillation of coal, there is ordinarily con
cloudiness. Moreover, in certain instances, al
tained a dark liquid called coal tar which upon
kali solutions containing these tar acids become
distilaltion produces oils of different boiling
very viscous and even solidify at temperatures of
40° F. or lower, with the result that emulsion dif 20 ranges and a residual pitch. It is common prac
tice in the coal-tar industry to distill coal-tar
ficulties are encountered during use of such solu
This invention relates to a method and reagent
into several fractions; one being light oil, boiling
tions. Gasoline treated with alkali solutions con
taining high-boiling tar acids may acquire an un
up to about 200° 6., another known as middle oil
organic sulphur compounds.”
such as, phenol, cresols and one or more xylenols.
boiling from about 200 to 250° 0., a third frac
pleasant odor. A further di?iculty which is some
times experienced is the interference with the 25 tion known as heavy oil boiling from about 250
to 300° C., and a fourth fraction known as an
analytical determination of the mercaptan sul
thracene oil boiling from about 300 to 350° C. It
phur content of the treated gasoline. Di?iculty is
is common practice to treat fractions with aque~
experienced in determining the end point during
ous alkali solutions to remove therefrom the acid
the titration of the gasoline using the silver ni
trate-ammonium thiocyanate titration method 30 ic substances contained therein. The resulting
aqueous alkali solution is neutralized with acid
disclosed in the May 13, 1941, analytical edition
to recover the acidic substances extracted from
of “Industrial and Engineering Chemistry,” vol
the various oil fractions. The acidic substances
ume 13, page 298 in an article by Bell and Agruss
are then fractionated to obtain various phenols
entitled, “Analytical procedure for mixtures of
In the fractionation, the separation is made be
We have discovered that all of the foregoing
tween those constituents boiling below and above
diihculties can be eliminated if the high-boiling
approximately 220° C. The residual liquid from
tar acids are treated to eliminate therefrom, those
the
fractionation of the tar acids is the material
constituents soluble in water which impart to the
herein referred to as “high-boiling tar acids”
aqueous solution a greenish-black color in the 40 and shows the following distillation analysis:
presence of substantially acid-free ferric chloride.
“
°C.
It is not certain whether or not the substances
Initial boiling point ____________________ __ 100
which cause the dimculty are those substances
which turn aqueous solutions a greenish-black 45 5% off ________________________________ __ 220
10% off _______________________________ __ 229
upon addition of ferric chloride, but if those sub
stances which do turn the solution a greenish
black are removed from the tar acids, the remain
ing tar acids cause no di?iculty when used in
alkali solution to treat petroleum oils.
50
An object of the invention is to provide an
improved method for removing weakly acidic
bodies from otherwise neutral organic water-im
miscible ?uids.
Another object of the invention is to provide 55
20%
30%
40%
50%
60%
70%
80%
90%
off
off
off
off
off
off
off
off
_______________________________ __
_______________________________ __
_______________________________ __
__
___
_______________________________ __
_______________________________ __
_______________________________ __
___
___
95%
off ____
Dry point
____ __
247
261
270
280
296
312
326
350
375
_____ __
400
2,405,872
3
4
A solution was prepared, using high-boiling tar
acids made in the manner just set forth and ob
tained from the Reilly Tar & Chemical Corpora
.
A sample of the same gasoline was treated with
7.6% by volume of the solution containing 20%
by weight of soduim hydroxide, 20% by weight of
water-washed high-boiling tar acids and 60% by
tion by mixing together 20% dry sodium hydrox
ide, 20% tar acids and 60% of water, by weight.
weight of water in a counter-current tower.
The resulting solution was not entirely homoge
mercaptan sulphur of the‘ gasoline was lowered
neous, but contained liquid or solid material
which had a shiny appearance. 300 cc. of Dubbs
cracked gasoline from Texas crude oil was agi
tated with ‘7% by volume of the'solution and the 10
from 0.096% to 0.005. A comparison of the oc
tane numbers and lead susceptibilities of the gas
oline before and after treatment is given in the
The
following table:
resulting gasoline Was colored yellow-brown.
The treating solution continued toiimpart the
yellow-brown color to successive batches of gas
oline. In addition, the gasoline was cloudy. An
Table
Octane numbers
attempt was made to determine the mercaptan 15
Without
sulphur content by the silver nitrate-ammonium
thiocyanate titration method, but considerable
difficulty was experienced in determining the end
point of the titration. Moreover, emulsion di?i
T. E. L. T. E. L. '1‘. E. L. T. E. L. T. E.
0.5 cc.
1.0 cc.
2.0 cc.
3.0 cc
I Untreat ed
culties were encountered when an attempt was 20
gasoline. .__Treated gaso
68. 6
71.0
72.0
73. 4
75.0
line _______ _ _
68. 8
71. 6
73. 5
75. 3
77. 0
made to counter-currently contact gasoline with
These ?gures show a notable increase in lead
susceptibility of the treated over the untreated
gasoline. In order to make a '72 octane gaso
ing together 20% of NaOH, 20% of water-washed, 25 line from the treated sample, only 0.6 cc. of tet
raethyl lead was required, thereby effecting a
high-boiling tar acids and 60% of water by
the treating solution in a counter-current con
tact tower.
Another treating solution was prepared by mix
weight. The water washing of the high-boiling
tar acids was carried out by vigorously agitating
high-boiling tar acids with an equal volume of
boiling water for one-half hour and drawing oif
the upper aqueous layer and repeating the wash
ing step with an equal volume of fresh ‘boiling
water three additional times. Each aqueous layer
was tested by adding thereto a few drops of
freshly prepared aqueous ferric chloride solution
containing approximately 2% of'ferric chloride.
The aqueous layer from the ?rst two washings
saving of 40% in the quantity of tetraethyl lead
over that necessary to vbring the'untreated sam
ple up to 72 octane.
, It should be understood that water-washing of
the high~boiling tar acids need not be done with
boiling water, nor is it necessary to use the ratio
of acids to water or the particular number of
washes herein specified. Water of lower tem
perature may be used, but will require a larger
amount of washing or a longer washing period
to remove the objectionable substances from the
gave a greenish-black color upon addition of the
tar acid. Larger ratios of water to tar acids will
reduce the number of washings. We prefer wa
ferric chloride while the aqueous layer from the
last two washes gave a violet-black color with 40 ter approaching the boiling point in temperature
because of the viscous character of the high
the addition of the ferric chloride. The concen
boiling tar acids. If it is desired to use cold wa
tration or amount of ferricv chloride solution used
in the test is not important since the color re
ter or water which is only slightly warm, it may
action occurs in " the presence of a very small
be expedient to dilute the tar acids with an inert
water-immiscible fluid to lower the Viscosity, and
amount of the ferric chloride. It is important
that the ferric, chloride be substantially acid
to remove the diluent before adding the tar acids
free since acid interferes with the color change.
Therefore, freshly prepared ferric chloride solu
tion should be used.
The alkali solution prepared by using the wa
ter-washed tar acids was homogeneous even when
cooled to 40° F. A sample of the same Dubbs
cracked gasoline from Texas crude was treated
with 7% by volume of the aforesaid alkali solu
tion containing the washed high-boiling tar acids.
The treated gasoline was only slightly colored,
to the alkali solution.
1
The extent of water-washing in any case, is
determined by testing the wash water with ferric
chloride solution. When the color of the washed
Water upon addition of ferric chloride, changes
from greenish-black to violet-black, the washing
is sufficient.
no objectionablerforeign odor, caused no trou
blesome emulsoin in the treating step and could
Our invention is not limited to the particular
manner for removing the objectionable sub
stances from high-boiling tar acids, but it is in
tended to include the use of high-boiling tar acids
as solubility promoters where tar acids are free
of substances which dissolve in Water to give a
be titrated for mercaptan sulphur with ease.
60 greenish-black color on addition to the water of
contained no appreciable'haze or cloudiness, had
There was no difference in the amount of mer
captan sulphur removed by the solution contain
ing the unwashed and the washed high-boiling tar
acids.
The mercaptan sulphur content of the gasoline
was lowered from 0.096% to 0.0231% in a single
treatment with 7% by volume of the treating
solution. A treating solution containing 20% by
volume of solid sodium hydroxide, 20% of water
washevd tar acids, 5% of commercial cresol and
55 %'of water by weight, when contacted’ with the
same gasoline in an amount of 7% by volume,
lowered the mercaptan sulphur content to
0.01'76%_and caused no objectionable odor, color,
haze or emulsion.
ferric chloride.
Although for purposes of demonstrating the
invention we used a solution made by mixing to
gether 20% of sodium hydroxide, 20% of water
washed high-boiling tar acids and water, the
composition of the solution may vary within wide
limits. In order to obtain appreciable removal
of mercaptans from hydrocarbon oils the treat
ing solution should contain at least 5% by weight
of free alkali metal hydroxide, i. e. alkali metal
hydroxide over and above that necessary to re
act with other constituents of the solution, and
at least 5% by weight of high-boiling tar acids,
but preferably in excess of 10%. Either sodium
75 or potassium hydroxide or a mixture thereof may
2,405,872
5
be used as the alkali metal hydroxide.
6
Care
should be exercised to keep the free alkali hy
constituents which in ‘aqueous solution turn
greenish-black in the presence of ferric chloride
droxide concentration of the solution below the
point at which the solution becomes so viscous
as to cause emulsion dif?culties during the treat
to enhance the ability of said solution to extract
said sulphur compounds from the hydrocarbon
oil.
3. Method in accordance with claim 1 in which
the aqueous solution contains at least 10% by
droxide concentrations up to 25% by weight are
weight of high-boiling tar acids in the form of
satisfactory. The washed tar acids may be added
their reaction products with alkali.
to the solution as such or in the form of alkali 10
4. The method of removing mercaptans from
gasoline which comprises contacting the gasoline
metal salts. The tar acid content of the solu
tion may extend up to the maximum amount
with an aqueous solution made by mixing to
gether approximately 20 parts by weight of al
which is compatible with the solution and will
kali metal hydroxide, 20 parts by weight of high
vary with the alkali concentration of the solu
tion. Other solubility promoters such as phenols, 15 boiling tar acids which have been water washed
low boiling fatty acids and naphthenic acids may
to remove therefrom objectionable gasoline-sol
uble color-imparting‘bo'dies and sufficient water
be usedwas components of the treating'solution.
Treatment of gasoline and other hydrocarbon
to keep the alkali metal hydroxide and tar acids
in solution.
distillates by means af alkali solutions contain
5. The method of improving high-boiling tar
ing tar acids prepared in accordance with our 20
invention may take place at ordinary atmospheric
acids for use as solubility promoters in alkali
temperature and preferably within the range of
solutions which consists in washing said tar
approximately 40-100” F. The ratio of treat
acids with at least two volumes of water until
the wash water changes from greenish-black to
ing solution to oil undergoing treatment will de
pend on the nature and amount of acidic bodies 25 violet-black color upon addition of ferric chlo
ride.
contained in the oils, but in general, a ratio of 5
6. The method of improving high-boiling tar
to 20% of treating solution by volume based on
acids, for use as solubility promoters in alkali
the oil undergoing treatment can be used with
solutions which consists in washing said acids
good results. The treating solution can be re
generated by boiling or by stripping the absorbed 30 with at least two volumes of hot water until the
wash water no longer turns greenish-black upon
acidic constituents therefrom by means of steam
at temperatures of approximately 220-250" F.
additionof ferric chloride.
7. The method of removing from high-boiling
It is claimed:
tar acids substances which discolor gasoline
1. The method of removing weakly acidic sul
phur compounds from hydrocarbon oil which 35 when contacted with alkali solutions containing
said tar acids which consists in washing said tar
comprises contacting said oil with aqueous solu
acids with at least four volumes of boiling water,
tion containing at least 5% by weight of free
the amount of water being su?icient to remove
alkali metal hydroxide and a su?icient amount
from said tar acids substances which turn water
of the soluble reaction products of an alkali and
high-boiling tar acids which have been freed 40 containing them greenish-black upon addition of
ferric chloride.
by water washing of constituents which react
with ferric chloride in aqueous solution to im
8. Method in accordance with claim 1 in which
part thereto a greenish-black coloration to en
the aqueous solution contains not less than 10%
by weight of free alkali metal hydroxide but less
hance the ability of said solution to extract said
ing steps. Free sodium hydroxide concentrations
up to 20% by weight and free potassium hy
sulphur compounds from the hydrocarbon oil.
2. The method of removing weakly acidic sul
phur compounds from hydrocarbon oil which
comprises contacting said oil with aqueous so
lution containing at least 5% by weight of free
" than that amount which causes the solution to
be so viscous as to cause emulsion difficulties
when mixed with the hydrocarbon oil, and in excess of 10% by weight of high boiling tar acids
in the form of reaction products with the alkali
alkali metal hydroxide and a su?icient amount 50 metal hydroxide.
of the soluble reaction products of an alkali and
higher boiling tar acids which have been washed
sufficiently with water to remove therefrom those
GEORGE W. AYERS.
DANIEL M. BARTON.
" " "
Документ
Категория
Без категории
Просмотров
0
Размер файла
466 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа