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Патент USA US2407263

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Patented Sept. 10, 1946
2,47,253
umrso STATES PATENT‘ omce ’
PROCESS FOR STABILIZING‘OR DEACTIVAT
ING' SLUDGES, PRECIPITATES, AND RESI
DUES OCCURRING OR USEDIN THEQMAN
UFACTU-RE OF TETRAALKYL LEADS
Adrian L. Linch, Wilmington; DeL', assignor to
E. I. du- Pont de Nemours & Company, Wil-t
min'gton', Del., a corporation of. Delaware
No'Drawingr Application September‘ 116‘, 1942,
Serial No. 458,582
8' Claims.
I
(Cl. 260-437)
2
'I'h'is'invention' relates to‘ a process for stabiliz;
ing or deactivating'slud'ges; precipitates and res
iduesoc‘curring or‘ used in the‘ manufacture of
tetraalkyl leads, and which normally tend to pro
mote decomposition andigni'tion. of the tetra
alkyl leads‘ thatlmayibe' contained therein.
It is known that alk'yl. metal compounds in
general are quite unstable and decompose read
ily, particularly in the; presence of air or oxygen.
It has also been found, that these alkyl metal
compounds are‘ particularly unstable when ad
sorbed on materials whichpresent a large sur
face area per unitvolume such as silica gel, clays,
ing application Ser. No. 393,680;
However, even
in these cases the sludges which are deposited
by the"v action of. the oxidizing agent and which
invariably contain tetraethyl lead, tend to ignite
when‘. exposed to air thus‘ presenting. serious ig
nition; hazards, making it desirable that even
these sludges should be deactivated. during. their
formation'or afterwards to permit of their re
moval anddi'sposal in. a safe manner.
It is. therefore an object of thisinvention' to
provide'a process for stabilizing sludges, precip
itates: and‘ residues occurring in: the manufacture
of tetraalkyl lead compounds whereby the igni
tioni hazard presented by‘ the, lead alkyl com;
rials of . similar structure which materials appear 15 pounds in contact with: such catalytic surfaces.
to exert a catalytic effect in the: decomposition
is reduced. or completely overcome.
of. these alkyl metal compounds. Even tetra
It is‘ a still furtherv object‘ of the invention to
alkyl leads such asv tetraethylrlead which is known
render‘ inactive. materials-which. tend to exert a
to be somewhat more stablev than some of the
catalytic. effect in the‘ decomposition of tetra
other alkyl. metal compounds‘ decomposes and 20 alkyl leads‘ in the presence of air thus permit
often ignites in the presence of oxygen when
ting the safe use. of such, materials as ?lter aids,
small amountsare' adsorbed on materials that
in the manufactureof tetraalkyl‘ lead.
offer. extended surface areas, particularly when
I have found that sludges, precipitates and resthe masses: containing. the tetraethyl lead are‘
iduesY occurring or involved in the production of‘
exposed ‘to temperatures‘ somewhat higher. than 25 tetraalkyl. leads‘ which o?er large surface areas
normal atmospheric‘ temperatures; The‘ tend‘
per unit: volumeandiwhich- normally tend to exert
catalytic eifect and cause- decomposition and-ig
ency‘to' oxidize and ignite, of course; varies with.
the substancewith which. thezalkyl; metal com
nitionv of. the? tetraalkyl lead: whichmay. be: con.
pound is incorporated, some materials apparent»
tain'edtherein can be renderedinactiverconvem
1y exerting a greater catalytic effect than. others
iently'and? economically by washingor otherwise’v
in promoting ignition. of the alkyl‘lead comtreating them? with , solutions. or: dispersions; of . oil
pounds.
soluble-copper, or iron saltsiofl organic carboxylic
acids; The'se'l stabilizing; or deactivating agents
Inv the manufacture of tetraalkyl leads, such 1
appear tobe preferentially‘absorbed by the active
as tetraethyl lead, tetramethyl‘ lead. and the mixed
ethyl-methylleadzcompounds,sludges areiformed 35 materials; which materials- retain. their capacity
to‘ absorb the tetraalkyl lead, although-they no
from which-it is‘di?icult and, from, a practical
longer have the property of inducing“ ignition of
standpoint, impossible to entirely“ free from the
alkyl lead compounds during the. normal steam
the tetraalkyl lead absorbed therein.
'
distillations or decantation operations; There‘ is,
By the/terms sludges, precipitates and‘ residues
therefore, carried through-the! process'very ?nely 40 I include-those?lte'r aids which may be employed
divided leadand impurities such as bismuthzcom
in the production of: the tetraalkyl leads and
pounds. which, although‘ presentv in very small
which- o?er a large‘ surfacea'rea per unit volume
amounts, ?nally‘ are deposited‘ as‘ sludges in’ the
and" are known to accelerate decomposition of
alumina, earths, asbestos; charcoal, and mate-v
pipe's'and tanks and other processing equipment,
the'tetraalkyl leads on- exposure to air or oxy
and these sludgesiwh'ich contain‘ tetraethyl lead 41.51 gen~ such‘ as clays,’ silica, earths, charcoal, etc.
adsorbed therein when exposed: to‘ oxygen or‘ air 1
These ?lter aid'siare rendered inactive by treat
oftenlignite; thus ' presenting-serious ignition and
ing“ them with copper‘ or iron salts’ of organic
carboxylic‘ acids either before or after they are
employed in the process. The effectiveness of
of practically‘ all the sludge" forming materials 50 these copper" or iron salts in the deactivation of
from the tetraethyl lead" after its distillation, such
these active materials is not materially reduced
as by controlled blowing‘ with air or oxygen
by washing the deactivated materials with Water
with» agitation,.preferably" under a layer‘ of wa--"
or other‘ solvents or‘ by drying them down prior
explosion hazards in the‘ process.
'
Methods havev been advanced for‘the removal
ter, followed by separation‘ of‘ the“ precipitated
to use.
sludge, as more particularly ‘described in copend 55 The copper or iron salts of organic carboxylic ’
2,407,263
3
acids, being oil soluble compounds, may be dis
solved directly in the tetraalkyl lead before the
sludge is precipitated by the method more par
ticularly described in copending application Ser.
No. 393,680. _ They may be added to the tetra
4
or after drying, for it has been found that they
do not again become active even after being dried,
or by being washed by the solutions that are ?l
tered
therethrough.
H
.
>
.,
.
,
The following examples are given? to. illustrate
the invention. The parts used are by weight.
alkyl lead after the sludge has been precipitated
but before the tetraalkyl lead and sludge are sep
EXAMPLE 1
arated; they may be added to a slurry of the
About
4
parts
of
cupric oleate were dissolved
tetraalkyl lead and sludge; or they may be dis
in
approximately
20,000
parts of crude tetraethyl
10
solved in a suitable solvent and agitated with
lead. The sludge forming impurities were then
the separated sludge. These deactivators may
precipitated by blowing with air as more par
be employed as a dispersion or a suspension in
any type of solvent that may be desired for use
ticularly described in the copending application
Ser. No. 393,680. After the precipitation was
in the treating of the tetraalkyl lead.
complete, the tetraethyl lead and sludge were agi
In general, the quantity of stabilizing agent 15 tated for 15 minutes and ?ltered.
required will be from about 1 to 10% based on
A small portion of the ?lter cake was then
the dry weight of the active material to be treat
ed so that in the treatment of the sludges occur
ring in or to be precipitated from the crude tetra
ethyl lead in the usual methods of manufacture
in which there are usually not more than two
- tested for ignition activity by placing it on a ?lter
paper, wetting it with a small quantity of tetra
ethyl lead and heating on a steam bath. No signs
of ignition or of charring of the ?lter paper were
noted even after 24 hours heating.
parts of precipitated sludge obtainable from the
A sample of sludge which had been produced
1,000 parts of crude tetraethyl lead, it has been
in a similar manner from the same batch of
found that if 0.1 to 0.2 part of the stabilizing
tetraethyl lead, except that the addition of cop
agents be employed per 1,000 parts of crude tetra 25 per oleate had been omitted, when tested for ac—
ethyl lead the sludges precipitated therefrom will
tivity as outlined above, ignited shortly after the
be stabilized and when dried or heated will not
sample was placed on the steam bath.
cause ignition of the tetraethyl lead that may be
EXAMPLE 2
contained therein. The amount of deactivator
Approximately 1,000 parts of crude tetraethyl
employed may, of course, be varied over a wide 30
lead were placed in a suitable container provided
range. Good results have been obtained with
with an agitator. About 100 parts of water were
concentrations as low as 0.05% of the deactivator
added, and the sludge was precipitated by air
based on the weight of the dry active material.
blowing and collected in the water layer as dis
While amounts as high as 100% based on the
dry weight of the active material may be em 35 closed in the previously mentioned application
ployed, the use of excessively large amounts over
Ser. No. 393,680.
After the precipitation treatment was complete,
that actually required to deactivate the active
the clear tetraethyl lead was decanted from the
material merely contributes unnecessarily to the
water layer in which the precipitated impurities
In treating dry materials such as the ?ltered 40, were suspended. One part of ferric naphthenate
was added to the aqueous sludge suspension, and
tetraethyl lead sludge, ?lter aids or the like, the
the mixture was vigorously agitated for 30 min
quantity of stabilizing agent required may be dis
cost of the process and serves no useful purpose.
solved in a suitable solvent.
Good results have
been obtained with solutions of the deactivator
of concentrations as low as 0.05%.
The upper
utes. The mixture was ?ltered, and a portion of
the precipitated sludge was tested for ignition ac
' .tivity as previously described.
It was found to
be inactive. A sample of sludge taken before the
limit of concentration will, of course, usually be
ferric naphthenate was added was similarly
determined by the solubility of the deactivator
tested and found to promote ignition of tetra
in the particular solvent employed. It is, of'
ethyl lead.
.
.
course, advantageous to employ a su?icient
amount of solution to insure complete contact 50 As illustrated in the above examples, the sta
bilizing agent may be added directly to the tetra
with all the material to be deactivated. If dis
alkyl lead to effect deactivation of the sludge that
persions or suspensions of the deactivator are
may be precipitated by air blowing or by any other
used, it will be found advisable to employ some
process, or the sludge may be collected and sepa
what larger quantities and concentrations in
order to insure adequate contact between the ac 55 rated from the tetraalkyl lead and stabilized by
treatment with a suspension or solution of the
tive material and the stabilizing agent within a
deactivating metal salts.
reasonable time.
,
When 10 parts of an active sludge were treated
Where the sludges or precipitates settle out in
with 50 parts of a solution containing 0.1 part of
the pipe lines or other processing equipment dur
one of the following’ oilsoluble salts of the car
ing the manufacture or puri?cation of the tetra
boxylic acids mentioned, completev deactivation
alkyl leads, they may be deactivated, to insure
of the sludge was effected so that when tested as
safety in their removal or during repair of the
described in Example 1 no ignition or charring
equipment, by pumping a solution of one of the
was observed even after 72 hours of heating:
deactivating materials through the apparatus for
cupric oleate, cupric naphthenate, ferric oleate,
asuf?cient period of time to insure complete con
ferric stearate, cupric palmitate, ferric naph
tact with all the sludge to be deactivated, which
thenate, ferric palmitate, and the copper (cupric
is usually accomplished in from 15 to 30 minutes.
and cuprous) and the iron (ferric and ferrous)
Where a quantity of the sludge is obtained in
salts of stearic acid, Z-ethyl caproic acid, lauric
cleaning out the equipment, it may be transferred
acid, linoleic acid, hydroxy stearic acid, naphthyl
to a suitable tank and agitated with a solution of
stearic acid, ricinoleic acid, alkylated benzoic
the deactivator until complete deactivation is
acids such as amyl benzoic acid, para dodecoxy
effected.
benzoic acid, stearoyl benzoic acid, and mixtures
.The ?lter aids may be washed with a solution
of acids obtained by saponi?cation of coconut oil,
of the deactivating agent prior to their use in_
the process. They may be employed either before 75, tallow and‘ other glycerides, and abietic acid,"
memes"
5.
6
Wherethe untreated sludge "employed in these
placed‘ vin- a suitable tank- or washer, ‘and’ 2 - parts
of- cuprou's' n-aphthenate were dissolved therein.
The“ contents or the‘tank were‘ aerated and‘ agi
tated for-two hours as-disclosed in the copending'
application: Sen. No. 393,680.. After a. settling
period of a few minutes, the clear mixtureof lead
alliyls was decanted from the aqueous layer’ and
theraqueous- mixture was ?ltered. A portion of
tests wassubjected to the same ignition test‘ as‘
described- in Example: 1, it ignited shortly after
being’ placed on thesteam bath.
As previously stated the invention may be em~
ployed to stabilize active ‘?lter aids which are
to be used in tetraalkyl lead ?ltration. These
materials may be washed in a solution of? one of
the deactivators and rendered suitable for tetra
the~?lter cake was tested on the steambath as
alkyl lead ?ltration. Thefollowing ?lter aidsas 10 described in Example 1, except that‘ thei?liter.
well- as a number of other‘ materials of similar
structure‘ were wet with tetraethyl lead and
placed on a steam bath as- described-'lin- Example
1 above. All were found» to initiate the‘ ignition
of tetraethyl lead. Ten parts‘ of: each-' of these
materials were then agitated for‘ several» hours
cake‘ »(sludge)' was wet. with mixed lead .alkyl
compounds rather. than with tetraethyl. lead
No= decomposition or ignition of. the lead: .al-kyls
was noted. A similar experiment was carried; out
P in. which- no stabilizing‘ agent. was. added‘.
This
sludgev ignited the mixed. alkyls . when the: stability
with; 50 parts of‘ a benzene solution of ~ the» cop
per i and- iron salts ‘of the carboxylic acids- Oil‘ the‘
test-was made‘.v
A further use: of. this: invention: will; be found
tered and portions of the?lter cakes‘ ‘were wet
with tetraethyl lead and placed‘ on a steam bath.
Results of these tests were as given in‘ the fol
copper and iron salts may be dissolved directly
in. the. tetraalkyl lead‘. so that any sludge. which
precipitates out .on standing will be rendered. in
in the-storage of'thef crudeitetraalkyl leads be
concentrations‘ given in the‘ following table. Af~~
ter- the- agitation period the solutions‘ were-?l 20 forehthey' are de-sludged. These deactivating
active-byv contact with‘ the deactivating agent;
lowing table:
1 In testing the: activity of the‘ sludgesbeforev or:
M aterial
Wash solution.
afterrtreatmentiwith the deactivating. agents,.it
' “teat'gsgath
will‘.bei_no.ted that. tetraethyl or other. alkyl :lead
was added. to the‘ residues. This was to make
sure; there was su?icient tetraalkyl lead-present
_None ________________ » ignited;
_ .l%vferric stearate _____ __ No decompo
-
sition.
None _________________ ..
Ignited:
0.2% ferric oleatc _____ __
No decompo
sition.
Yellow lead oxide (N. F.
None _________________ __
VI).
Do __________________ __ 0.5% cuprous naphthe-
nate.
Bismuth subnitrate _____ __
Ignited.
No decompo
sition.
None ____________ _,______
Ignited.
Do __________________ ,_ 0.2% ferrous palmitate. No decompo‘
sition.
Bismuth oxide (from hy-
None _________________ __ Ignited.
drolysis of Bi(N03)3).
D0 __________________ _ _
0.5% cubric oleate ____ __
No decompo
sition.
Ferric oxide (anh). ..... __
None _________________ ._
Ignited.
Do __________________ __ 0.2% cupric naphthe-
nate.
No decompo
sition.
Activated Alumina _____ _.
None _________________ __
Ignited.
Do __________________ __
0.2%cuprouspalmitate.
No decompo
sition.
Dccolorizing charcoal ____ __
None _________________ __
Do __________________ __ 0.2%
ferric
nate.
naphthe-
Ignited.
No decompo~
sition.
30
to. ignite; under the. conditions‘ employedyif the
sludge was not fully inactivated, for in some‘ ins
stances, it is possible: that; the amount of‘ alkyl
lead may be reduced to such a small amount that
ignition might not be noted. While the elimina
35 tion of the alkyl lead from the residues to such
an extent does not ordinarily take place, the
tests were made under conditions favoring ig
nition provided the sludge or ?lter aid was active.
This invention makes possible the deactivation
of the ignitable sludges and residues occurring
40
in the manufacture of tetraalkyl lead compounds
and is of particular value in eliminating ?re and
explosion hazards involved in the removal and
disposal of such sludges from the process and in
overcoming the potential ?re hazard arising from
° the collection of such sludges and precipitates
which accumulate in various places in the proc
essing equipment and which when exposed to air
often ignite with considerable damage. The in
Approximately 1,000 parts of crude tetraethyl
lead and an equal weight of water were placed 5 O vention also permits the use of ?lter aids which,
unless rendered inactive, tend to cause ignition of
in a washer. Five parts of ferric stearate were
any absorbed tetraethyl lead when they are ex
then added and the sludge vwas precipitated and
posed to the air. Any other absorbent materials
removed from the tetraethyl lead by the method
which for any reason may become saturated with
disclosed in the copending application Ser. No.
tetraethyl lead in or about the plant in which
393,680. After this operation was complete, the
it is being manufactured may be rendered in
tetraethyl lead was removed by decantation, and
active by washing or otherwise treating with
the aqueous layer containing the sludge was ?l
stabilizers of the type described so that poten
tered. A portion of the ?lter cake was then test
EXAMPLE 3
ed on the steam bath as described in Example 1.
No decomposition or ignition of the tetraethyl
lead was noted.
EXAMPLE 4
As previously stated, sludges found in tetra
tial ?re hazards may be removed as far as pos
sible. Lagging on pipe which due to leaks may
60 become saturated with tetraethyl lead and which‘
have been known to cause its ignition can be in
activated by treating such lagging with the de
activating agents.
ethyl lead are also found in other lead alkyls
I claim:
which are manufactured from commercial lead. 65
l. The process for inhibiting the spontaneous
An example is the mixed tetramethyl-ethyl com
ignition of tetraalkyl lead compounds adsorbed.
pounds of lead, formed when a mixture of methyl
on sludges which are precipitated from crude
chloride and ethyl chloride is reacted with lead
tetraalkyl lead compounds and which sludges
sodium alloy. All examples in which tetraethyl
normally tend to cause spontaneous ignition of
lead is speci?ed are equally workable with these 70 the tetraalkyl lead compounds adsorbed thereon
mixed lead alkyls.
when exposed to oxygen, which comprises incor
Approximately 8,000 parts of crude mixed tetra
porating with’ such sludges a compound of the
methyl-ethyl lead compounds (tetramethyl lead,
group consisting of oil soluble copper salts of
carboxylic acids and oil soluble iron salts of
trimethyl ethyl lead, dimethyl diethyl lead,
methyl triethyl lead and tetraethyl lead) were 75 carboxylic acids.
2,407,263
7
2. The process for inhibiting the spontaneous
ignition of tetraethyl lead adsorbed on sludges
which are precipitated from crude tetraethyl lead
ignition of tetraethyl lead adsorbed on solid ma
terials which present a large surface area per unit
volume and which normally tend to cause spon
taneous ignition of the tetraethyl lead adsorbed
and which sludges normally tend to cause spon
thereon when exposed to oxygen, which com
taneous ignition of the tetraethyl lead adsorbed
prises incorporating with such materials an oil
thereon when exposed to oxygen, which com
soluble copper naphthenate.
prises incorporating with such sludges a com
6. The process for inhibiting the spontaneous
pound of the group consisting of oil soluble cop
ignition of tetraethyl lead adsorbed on sludges
per salts of carboxylic acids and oil soluble iron
salts of carboxylic acids.
10 which are precipitated from crude tetraethyl lead
and which sludges normally tend to cause spon
3. The process for inhibiting the spontaneous
taneous ignition of the tetraethyl lead adsorbed
ignition of tetraalkyl lead compounds adsorbed
thereon when exposed to oxygen, which com
on solid materials which present a large surface
prises incorporating with such sludges an oil sol
area per unit volume and which normally tend
uble copper naphthenate.
to cause spontaneous ignition of the tetraalkyl
7. The process for‘inhibiting the spontaneous
lead compounds adsorbed thereon when exposed
ignition of tetraethyl lead adsorbed on sludges
to oxygen, which comprises washing such ma
which are precipitated from crude tetraethyl lead
terials with a solution of a compound of the group
and which sludges normally tend to cause spon
consisting of oil soluble copper salts of carbox
ylic acids and oil soluble iron salts of carboxylic 20 taneous ignition of the tetraethyl lead adsorbed
7
thereon when exposed to oxygen, which com
prises incorporating with such sludges an oil sol
uble copper oleate.
8. The process for inhibiting the spontaneous
ignition of tetraethyl lead adsorbed on sludges
which are precipitated from crude tetraethyl lead
and which sludges normally tend to cause spon
thereon when exposed to oxygen, which com
taneous ignition of the tetraethyl lead adsorbed
prises washing such sludges with a solution of a
thereon when exposed to oxygen, which com
compound of the group consisting of oil soluble
copper salts of carboxylic acids and oil soluble 30 prises incorporating with such sludges an oil sol
uble iron stearate.
iron salts of carboxylic acids.
ADRIAN L. LINCI-I.
5. The process for inhibiting the spontaneous
acids.
4. The process for inhibiting the spontaneous
ignition of tetraethyl lead adsorbed on sludges
which are precipitated from crude tetraethyl lead
and which sludges normally tend to cause spon
taneous ignition of the tetraethyl lead adsorbed
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