Note: Descriptions are shown in the official language in which they were submitted.
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CASE C-5224
SULFURIZED OLEFIN PROCESS
Sulfuri~ed olefins are well-known additives
in lubricating oil, cutting oil and the like.
Kimball, U.S. Pat. ~o. 2,249,312, describes such a
product. Eby, U.S. Pat. No. 2,708,199, describes a
similar product in which a sulfur halide is reacted
with an olefin using a lower alkanol promoter to
obtain an intermediate which is reacted with an alkali
or alkaline earth metal polysulfide. Myers, U.S. Pat.
No. 3,471,404, describes a product in which sulfur
monochloride is reacted with olefin to obtain an
intermediate which is reacted with sulfur and alkali
metal sulfide at a critical ratio of 1.8-2.2 gram
moles of metal sulfide per gram mole of sulfur. This
material is then refluxed forll-24 hours with aqueous
alkali metal hydroxide. In U.S. 4,204,969, an effec-
tive sulfurized olefin is made by reacting sulfur
monochloride with an olefin in the presence of a lower
alkanol promoter to obtain an adduct which is reacted
with sodium sulfide and sulfur in aqueous alkanol.
According to the present invention, a sulfur-
zed olefin having improved solubility especially in
alpha-olefin oligomer lubricating oil is made by re-
~; acting a monoolefin with S2C12 or SC12 to obtain
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an adduct which is reacted with sodium sulfide, sulfur
alkyl mercaptan and optionally sodium hydrosulfide in
an aqueous alcohol reaction medium.
A preferred embodiment of this invention is
a process for making a sulfurized olefin having
improved solubility in lubricating oil said process
comprising:
(a) reacting a sulfide halide selected from
SC12, S2C12 and mixtures thereof
with an aliphatic monoolefin containing
3-6 carbon atoms to produce an adduct:
(b) reacting said adduct with sulfur,
Na2S, an alkyl mercaptan containing
1-12 carbon atoms and optionally NaSH
in an aqueous alcohol medium at a
temperature of 50C up to reflux to
form said sulfurized olefin;
(c) recovering said sulfurized olefin from
the aqueous alcohol medium.
Although a useful product can be obtained
using either SC12 or S2C12, superior results
were obtained with S2C12 so this sulfur halide is
most preferred.
Useful olefins are the monoethylenically
unsaturated aliphatic hydrocarbons referred to as
aliphatic monoolefin containing 3 to 6 carbon atoms.
., :
.
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These include l-butene, 2-butene, isobutene,
l-pentene, 2-pentene, 2-methyl-l-butene, 3-methyl-l-
butene, 2-methyl-2-butene, l-hexene, 2-hexene,
3-hexene, 2-methyl-l-pentene, 2-methyl-2-pentene,
2-ethyl-2-butene and the like including mixtures
thereof.
Preferably the olefins are branched-chain
olefin such as isobutene, 2-methyl-l-butene, 2-methyl-
2-butene, 2-methyl-2-pentene and the like. More
preferably the ethylenic double bond adjoins a
tertiary carbon atom such as isobutylene, the most
preferred olefin.
The first stage reaction is preferably
conducted by adding the olefin to sulfur mono-
chloride. The olefin can be added as a gas or
liquid. Preferably it is added beneath the surface
of the sulfur monochloride as a liquid.
In practice the olefin is added until the
reaction with the sulfur monochloride stops as
20 indicated by loss of exotherm. An amount of 0.75-3.0
gram moles of olefin for each 0.3-0.75 gram mole of
sulfur monochloride usually suffices. A preferred
amount is 1.5-2.0 gram moles of olefin per gram mole
of sulfur monochloride.
The reaction between sulfur monochloride and
olefin will proceed without adding an alcohol
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promoter, and since alcohol will tend to cause
corrosion of metal equipment, it is not a highly
preferred method of conducting the first stage. The
use of an alcohol promoter, however, is included in
one embodiment of the invention. Lower alcohol
promoters which can be used in the first stage
contains from 1 to 4 carbon atoms. Typical examples
are methanol, ethanol, n-propanol, isopropanol r
isobutanol, tert-butanol and the like. A preferred
promoter is methanol. The amount of alcohol promoter
is preferably 0.001 to 0.3 gram moles for each
0.3-0.75 gram mole of sulfur monochloride.
The first stage reaction can be conducted at
any temperature high enough to cause the reaction to
15 proceed, but not so high as to cause decomposition of
the reactants or products. A useful range is
30-100C. A more preferred range is 40-75C and a
most preferred range is 50-60C.
The first stage reaction should be conducted
for a time sufficient to complete the reaction between
the sulfur chloride and olefin. This time is con-
trolled by the rate at which heat can be removed.
Olefin feed rate is preferably controlled to hold the
temperature within the desired range. When the
sulfur chloride has been consumed the temperature
will drop. External heat may be added to continue
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the reaction for a further time, but this does not
appear to be necessary. The overall time required to
complete the reaction depends upon the scale of the
process and can vary from a few minutes up to 12 or
more hours. The time is not critical.
During the first stage reaction HCl gas is
evolved so means should be provided to scrub the vent
gas from the reactor to remove HCl prior to releasing
it to the atmosphere.
In the second stage reaction, adduct from the
first stage is reacted with sodium sulfide, sulfur,
alkyl mercaptan and optionally sodium hydrosulfide in
an aqueous alcohol reaction medium. The second stage
is preferably carried out by charging aqueous sodium
15 hydrosulfide, sodium hydroxide, water, alcohol and
elemental sulfur flowers or powdered sulfur to a
reactor and then adding the adduct and alkyl mercaptan
to this at reaction temperature. The NaSH and NaOH
react toform sodium sulfide. Excess NaSH remains.
The sodium sulfide may be obtained from any
of a number of sources. For example, it can be made
by mixing approximately equal mole amounts of sodium
hydrosulfide and sodium hydroxide. If hydrogen
sulfide is available, it can be adsorbed in aqueous
25 NaOH to form a solution of sodium sulfide andtor
sodium hydrosulfide depending upon the amount of
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hydrogen sulfide adsorbed. Whatever the source, the
resulting solution should be adjusted with either
NaOH, NaSH or H2S so that the resulting solution
consists mainly of sodium sulfide and optionally
sodium hydrosulfide with little or no free sodium
hydroxide.
The amount of sodium sulfide can vary from
0.5-2.0 gram mole for each gram mole of sulfur
monochloride used in the first reaction stage.
10 Preferably the amount of sodium sulfide is 0.5-1.0
gram mole per mole of sulfur monochloride and most
preferably 0.6-0.0 gram mole per gram mole sulfur
monochloride.
Presence of NaSH is optional. Use of up to
15 0.5 gram moles of NaSH per mole of S2Cl2 has
given satisfactory results. A preferred amount is
0.1-0.3 gram moles and most preferably 0.25 moles per
mole of S2Cl2.
The amount of water can vary widely without
20 detrimental effect. Good results can be obtained
using 10-20 gram moles of water per gram mole of
sodium sulfide. This includes water added as such,
water in aqueous reactants and water which might be
formed by reaction of hydrogen sulfide or sodium
25 hydrosulfide with sodium hydroxide in forming sodium
sulfide solution.
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Alcohol is required in the second stage
reaction. Preferably, these are lower alcohols con-
taining 1-4 carbon atoms such as methanol, ethanol,
n-propanol, n-butanol, isobutanol, tert-butanol and
the like, including mixtures thereof. The preferred
alcohol is isopropanol either alone or mixed with
other alkanols such as tert-butanol.
The amount of alcohol can likewise vary over
a wide range. A useful range is 0.25-0.75 parts by
weight per each part by weight of water. A more
preferred range is 0.4-0.6 parts by weight alcohol
per each part by weight water.
The alkyl mercaptan can be added separately
to the aqueous alcohol reaction medium or it can be
mixed with the first stage adduct and the mixture
added to the aqueous alcohol containing the sodium
sulfide and sulfur. When added separately it is
preferred that it be added concurrently with the
first stage adduct to the aqueous alcohol containing
20 the sodium sulfide and sulfur. Sequential addition
can be used but it i8 not preferred.
Useful alkyl mercaptans include those in
which the alkyl group contains 1 to 12 carbon atoms.
Representative example of these are methyl mercaptan,
25 ethyl mercaptan, n-propyl mercaptan, i-propyl
mercaptan, n-butyl mercaptan, isobutyl mercaptan,
.. ..
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sec-butyl mercaptan, tert-butyl mercaptan, n-pentyl
mercaptan, isopentyl mercaptan, tert-pentyl mercap-
tan, 2-ethyl hexyl mercaptan, n-octyl mercaptan,
l-methyl-heptyl mercaptan, l-ethyl-decyl mercaptan
5 and the like including mixtures thereof.
of the foregoing the more preferred mercap-
tans are the tert-alkyl mercaptans. Of these the
more preferred are the tert-alkyl mercaptans
containing 4-8 carbon atoms. The most preferred
10 alkyl mercaptan is tert-butyl mercaptan.
The amount of alkyl mercaptan can vary over
a wide range. A useful range in which to test is
0.05 to 0.8 moles for each mole of sulfur mono-
chloride used in the first stage. A preferred range
15 is 0.08 to 0.5 moles of alkyl mercaptan per mole of
sulfur monochloride and a more preferred range is 0.1
to 0.4 moles per mole of sulfur monochloride. The
most preferred amount of alkyl mercaptan is 0.25 to
0.35 moles per mole of sulfur monochloride.
The preferred amount of sulfur added is
0-0.3 gram atom for each gram mole of S2C12.
More preferably, 0.05-0.15 gram atom of sulfur and
most preferably 0.1-0.15 gram atom are used per gram
mole of S2Cl2.
In a preferred mode of operation the mixture
of sodium sulfide, sulfur and aqueous alkanol is
~ , ..
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stirred and heated to reaction temperature and then
the adduct and alkyl mercaptan are added to it.
However, the reaction can be carried out in other
ways such as by adding the sodium sulfide, sulfur,
5 alkyl mercaptan and aqueous alkanol mixture to the
adduct or by mixing everything together and heating
the mixture.
Preferred second stage reaction temperature
is 50C up to reflux temperature. A more preferred
10 reaction temperature is 75-85C.
After the adduct and alkyl mercaptan have
been added to the sodium sulfide/sulfur/aqueous
alkanol mixture, which is usually completed in 1-8
hours, the mixture is preferably heated to reflux
15 just below for 2-8 hours to assure completion of the
reaction.
A very convenient way in which to make an
effective sulfurized isobutylene is to base the
amount of Na2S and NaSH (or NaOH plus NaSH or NaOH
20 plus H2S), sulfur and tert-butyl mercaptan on the
weight of S2C12 - isobutylene adduct. Following
this procedure the Kg of Na2S, NaSH, sulfur and
tert-butyl mercaptan per each 100 Kg of sulfurized
isobutylene is preferably 15-45:0-12:0-7.5:3-20:100,
25 more preferably 20-35:2-10:1-6:4-18:100 and most
preferably 25-30:4-8:2-5:5-15:100. After reaction of
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the adduct with sodium sulfide, sodium hydrosulfide,
alkyl mercaptan and sulfur the product is recovered
by conventional methods such as removing alkanol,
water washing and filtering.
The following example illustrates the manner
of making the sulfurized olefin.
EXAMPLE 1
A sulfurized isobutylene adduct was made by
adding isobutylene to sulfur monochloride at 50-65C
10 until reaction stopped. In a separate vessel was
placed 177.9g aqueous alcohol (64.7 wt~ isopropanol,
13.8 wt% tert-butanol, 20.3 wt% water), 23.4g water,
240.4g 29.09% aqueous NaSH solution (0.9 moles),
76.2g 81.6g 50% aqueous NaOH solution (0.95 moles)
15 and 12.3g (0.38 moles) sulfur. This was stirred at
75C while 255.3g of the above adduct and 32.0g
tert-butyl mercaptan (0.36 moles) were concurrently
added dropwise over a two hour period. Heat was
continued at reflux for three hours and then solvent
20 alcohol was distilled out up to 90C.
Vacuum was applied to remove more solvent. Heat was
stopped and when the mixture cooled to 65C the
mixture was washed with water. The aqueous brine
layer was removed and the organic layer was stripped
25 of volatiles under vacuum at 100-110C for one hour
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lZ60460
and then filtered a second time giving a clear amber
product which analyzed 47.7 weight percent sulfur.
EXAMPLE 2
In a reaction vessel was placed 188.4g
aqueous alcohol (same as in Example 1), 23 . 3g water,
246.0g 29.09 wt~ aqueous NaSH (1.27 moles), 78.0g 50%
aqueous NaOH (0.98 moles) and 6.1g sulfur (0.44
moles). This mixture was stirred and heated to 75C
and then 270.0g of the sulfurized isobutylene adduct
described in Example 1 was fed to the reaction mixture
together with 33.9g tert-butyl mercaptan over a two
hour period at 75 to reflux. Reflux was continued
for three hours and then solvent was distilled out up
to liquid temperature of 90C. Vacuum was applied
15 and heating stopped. When the temperature dropped to
65C water was added to wash the organic phase. The
lower aqueous brine layer was removed. The organic
phase was stripped under vacuum at 100-110C for one
hour and then filtered using a filter aid. Product
20 analyzed 43.6 weight percent sulfur.
EXAMPLE 3
In a reaction vessel was placed 100.41g of a
34.3 wt% aqueous solution of NaSH containing 1.03 wt%
Na2S, 37.27g of a 50 wt% aqueous NaOH solution, 4.0g
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of sulfur, 43.64g water and 86.19g of a mixture of
67.17 wt~ isopropanol, 16.89 wt~ tertbutanol and the
balance water. This was stirred and heated to 75C
at which time 133.47g of S2C12 - isobutylene
adduct made by adding isobutylene to S2C12 at 60C
to the point where no further isobutylene would react
was added concurrently with 6.66g tert-butyl mercaptan
over a two hour period. Stirring was continued at
reflux (about 80C) for three hours at which time
alcohol-water was distilled out up to 90C. Vacuum
was applied and distillation continued until 70C
liquid temperature at a vacuum of twenty-four inches
Hg. The mixture was then water washed at 70C. Wash
water was drained off and 1~ Dicalite filter aid
added. The mixture was stirred at 100-105C at 28"
Hg vacuum for one hour and then filtered. Product
analyzed 48.8 weight percent sulfur.
EXAMPLE 4
Another product was made following the same
20 procedure as Example 3 except using 98.27g 34.3 wt~
aqueous NaSH, 36.48g 50 wt~ aqueous NaOH, 2.95g sul-
fur, 42.70g water, 84.66g of same aqueous isopropanol
tert-butanol solution 16.33g tert-butyl mercaptan and
130.64g S2C12 - isobutylene adduct. The product
analyzed 46.4 weight percent sulfur.
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EXAMPLE 5
ThiC example followed the same procedure as
Example 3 except using 94.85g 35.04 wt% aqueous ~aSH,
35.96g 50 wt% aqueous NaOH, 6.22g sulfur, 29.77g
5 water, 99.83g 56.39 wt% isopropanol - 13.85 wt~ tert-
butanol - water solution, 16.21g tert-butyl mercaptan
and 129.70g S2C12 - isobutylene adduct. The
product analyzed 4~ weight percent sulfur.
The sulfurized olefins are especially useful
in lubricating oil formulations used in gear applica-
tions. The base oil may be a mineral oil or a syn-
thetic oil. Useful synthetic oils include olefin
oligomers such as decene trimer, tetramer and pentamermade by oligomerizing l-decene using a BF3 catalyst.
Useful olefin oligomers can be made using other
catalysts such as the aluminum alkyl Ziegler catalyst.
Likewise, other olefins can be used such as C6 14
l-olefins.
Synthetic alkylbenzenes can also be used such
as di-dodecylbenzene and the like.
Synthetic ester lubricating oil can also be
employed such as the alkyl esters of dicarboxylic
acid (e.g. di-2-ethylhexylsebacate), fatty acid esters
of polyols (e.g. trimethylolpropane, tripelargonate)
or complex esters of alkanols, alkane, polyols and
carboxylic or polycarboxylic acid.
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In this use the sulfurized olefin is added
in an amount sufficient to i~prove the EP property of
the lubricant. An amount of O.l to 10.0 wt % is
usually sufficient.
Fully formulated gear lubricants include
other conventional additives which perform various
functions. hxamples of such other additives are
corrosion inhibitors for ferrous and non-ferrous
metals such as tetrapropenyl succinic acid and bis-
(2,5-alkyldithia)-1,3,4-thiadiazoles. Antiwear addi-
tives such as alkyl or aryl phosphonates, phosphite,
thiophosphates, dithiophosphates, and phosphoric
acids. Also zinc dialkyl or diaryl dithiophosphate,
chlorinated hydrocarbons, sulfurized fatty esters and
15 amines.
Tests have been conducted which demonstrate
the EP effectiveness of the sulfurized olefin.
The tests were conducted in SAE 9O mineral
oil. The first was a 4-ball weld test (ASTM D2783)
20 in which a steel ball is rotated in loaded contact
with three fixed balls. The maximum load without
weld is recorded as the pass load.
The test additive was blended in the base
oil at a concentration which imparted l.O weight
25 percent sulfur to the oil. Results obtained were as
follows:
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Additive of Weld Load (Kg)
Example 1 315
Example 2 315
Example 3 315
Example 4 315
Example 5 315
In another standard test the present additive
was used as a componenet in a formulated gear oil.
The test was an L-42 High Speed Axle Test. Using the
additives of Example 1 or 2 gave a gear oil which
passed the test.
The mercaptan-capped sulfurized olefins of
this inventicn have been found to be much more soluble
in hydrogen-treated mineral oil and alpha-olefin
15 oligomer synthetic lubricating oil compared to the
same sulfurized olefin made without mercaptans. In
the first comparison blends were made at 4.0 weight
percent sulfurized olefin in a hydrotreated base oil,
a hydrocracked base oil an alpha-decene oligomer.
20 The blends were rated as clear or cloudy. The
results were as follows:
Additive Hydrotreated Hydrocracked Alpha-Decene
Base Oil Base OilOligomer
Example 1 clear clear clear
25 Example 2 clear clear clear
Example 3 clear clear cloudy
Example 4 clear clear clear
Example 5 clear clear clear
Standardl cloudy cloudy cloudy
30 1 Sulfurized isobutylene made without alkyl
mercaptan.
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Further solubility tests were conducted to
determine the solubility limits of the different
additives in a SAE 90W alpha-decene oligomer. The
5 following table gives the maximum concentration for a
clear solution and concentration at cloudy mixture:
Concentration (wt%)
Additive Clear Cloudy
Example 3 3 4
10 Example 4 8 9
Example 5 5 6
Standard - 1
These results show the improvement in
solubility in a synthetic alpha-olefin oligomer gear
15 oil base stock due to use of the alkyl mercaptan.
