Note: Descriptions are shown in the official language in which they were submitted.
REDUCING ALUMINOSILICATE SCALE IN THE BAYER PROCESS
Background of the Invention
This invention relates to compositions of matter and methods of using them to
treat scale
in various industrial process streams, in particular certain silane based
small molecules that have
been found to be particularly effective in treating aluminosilicate scale in a
Bayer process stream.
As described among other places in U.S. Patent 6,814,873
the Bayer process is used to manufacture alumina
from Bauxite ore. The process uses caustic solution to extract soluble alumina
values from the
bauxite. After dissolution of the alumina values from the bauxite and removal
of insoluble waste
material from the process stream the soluble alumina is precipitated as solid
alumina trihydrate.
The remaining caustic solution known as "liquor" and/or "spent liquor" is then
recycled back to
earlier stages in the process and is used to treat fresh bauxite. It thus
forms a fluid circuit. For
purposes of this application, this description defines the term "liquor." The
recycling of liquor
within the fluid circuit however has its own complexities.
Bauxite often contains silica in various forms and amounts. Some of the silica
is
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unreactive so it does not dissolve and remains as solid material within the
Bayer circuit. Other
forms of silica (for example clays) are reactive and dissolve in caustic when
added into Bayer
process liquors, thus increasing the silica concentration in the liquor. As
liquor flows repeatedly
through the circuit of the Bayer process, the concentration of silica in the
liquor further increases,
eventually to a point where it reacts with aluminum and soda to form insoluble
aluminosilicate
particles. Aluminosilicate solid is observed in at least two forms, sodalite
and cancrinite. These
and other forms of aluminosilicate are commonly referred to, and for the
purposes of this
application define, the terms "desilication product" or "DSP."
DSP can have a formula of 3(Na20-A1203-2Si02-0-2 H20) 2NaX where X represents
OH-, Cl-, CO3 SO42-
. Because DSP has an inverse solubility (precipitation increases at higher
temperatures) and it can precipitate as fine scales of hard insoluble
crystalline solids, its
accumulation in Bayer process equipment is problematic. As DSP accumulates in
Bayer process
pipes, vessels, heat transfer equipment, and other process equipment, it forms
flow bottlenecks
and obstructions and can adversely affect liquor throughput. In addition
because of its thermal
conductivity properties, DSP scale on heat exchanger surfaces reduce the
efficiency of heat
exchangers.
These adverse effects are typically managed through a descaling regime, which
involves
process equipment being taken off line and the scale being physically or
chemically treated and
removed. A consequence of this type of regime is significant and regular
periods of down-time
for critical equipment. Additionally as part of the descaling process the use
of hazardous
concentrated acids such as sulfuric acid are often employed and this
constitutes an undesirable
safety hazard.
Another way Bayer process operators manage the buildup of silica concentration
in the
liquor is to deliberately precipitate DSP as free crystals rather than as
scale. Typically a
"desilication" step in the Bayer process is used to reduce the concentration
of silica in solution by
precipitation of silica as DSP, as a free precipitate. While such desilication
reduces the overall
2
silica concentration within the liquor, total elimination of all silica from
solution is impractical
and changing process conditions within various parts of the circuit (for
example within heat
exchangers) can lead to changes in the solubility of DSP, resulting in
consequent precipitation as
scale.
Previous attempts at controlling and/or reducing DSP scale in the Bayer
process have
included adding polymer materials containing three alkyloxy groups bonded to
one silicon atom
as described in US patent 6,814,873 B2, US published applications 2004/0162406
Al,
2004/0011744 Al, 2005/0010008 A2, international published application WO
2008/045677 Al,
and published article Max HTTm Sodalite Scale Inhibitor: Plant Experience and
Impact on the
Process, by Donald Spitzer et. al., Pages 57-62, Light Metals 2008, (2008).
Manufacturing and use of these trialkoxysilane-grafted polymers however can
involve
unwanted degrees of viscosity, making handling and dispersion of the polymer
through the Bayer
process liquor problematic. Other previous attempts to address foulant buildup
are described in
U.S. Patent Nos. 5,650,072 and 5,314,626.
Thus while a range of methods are available to Bayer process operators to
manage and
control DSP scale formation, there is a clear need for, and utility in, an
improved method of
preventing or reducing DSP scale formation on Bayer process equipment. The art
described in
this section is not intended to constitute an admission that any patent,
publication or other
information referred to herein is "prior art" with respect to this invention,
unless specifically
designated as such.
Brief Summary of the Invention
At least one embodiment is directed towards a method for reducing siliceous
scale in a
Bayer process comprising the step of adding to a Bayer liquor an
aluminosilicate scale inhibiting
3
CA 2860803 2020-03-26
amount of reaction product between an amine-containing molecule and an amine-
reactive
molecule containing at least one amine-reactive group per molecule and at
least one - Si(OR)
group per molecule, where n = 1, 2, or 3, and R = H, C1-C12 Alkyl, Aryl, Na,
K, Li, or NH4, or
a mixture of such reaction products.
Another embodiment is directed towards a method for reducing siliceous scale
in a Bayer process
comprising the step of adding to a Bayer liquor an efficacious amount of a
reaction product
between: 1) an amine-containing small molecule, and 2) an amine-reactive small
molecule
containing at least one amine-reactive group per molecule and at least one -
Si(OR) õ group per
molecule, where n = 1, 2, or 3, and R H, C1-C12 Alkyl, Aryl, Na, K, Li, or N1-
14, or a mixture
of such reaction products, and 3) a non-polymeric amine reactive hydrophobic
hydrocarbon.
At least one embodiment is directed towards a method of reducing DSP in a
Bayer
process comprising the step of adding to the Bayer process stream an
aluminosilicate scale
inhibiting amount of a mixture of products as defined above.
Detailed Description of the Invention
While the present invention is susceptible of embodiment in various forms,
there is shown
in the drawings and will hereinafter be described a presently preferred
embodiment with the
understanding that the present disclosure is to be considered an
exemplification of the invention
and is not intended to limit the invention to the specific embodiment
illustrated.
For purposes of this application the definition of these terms is as follows:
"Polymer" means a chemical compound comprising essentially repeating
structural units
each containing two or more atoms. While many polymers have large molecular
weights of
greater than 500, some polymers such as polyethylene can have molecular
weights of less than
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500. Polymer includes copolymers and homo polymers.
"Small molecule" means a chemical compound comprising essentially non-
repeating
structural units. Because an oligomer (with more than 10 repeating units) and
a polymer are
essentially comprised of repeating structural units, they are not small
molecules. Small
molecules can have molecular weights above and below 500. The terms "small
molecule" and
"polymer" are mutually exclusive.
"Foulant" means a material deposit that accumulates on equipment during the
operation
of a manufacturing and/or chemical process which may be unwanted and which may
impair the
cost and/or efficiency of the process. DSP is a type of foulant.
"Amine" means a molecule containing one or more nitrogen atoms and having at
least
one secondary amine or primary amine group. By this definition, monoamines
such as
dodecylamine, diamines such as hexanediamine, triamines such as diethylene
triamine, and
tetraethylene pentamine are all amines, as well as hexamine diamine.
"GPS" is 3-glycidoxypropyltrimethoxysilane.
"Alkyloxy" means having the structure of OX where X is a hydrocarbon and 0 is
oxygen.
It can also be used interchangeably with the term "alkoxy". Typically in this
application, the
oxygen is bonded both to the X group as well as to a silicon atom of the small
molecule. When
X is C1 the alkyloxy group consists of a methyl group bonded to the oxygen
atom. When X is C2
the alkyloxy group consists of an ethyl group bonded to the oxygen atom. When
X is C3 the
alkyloxy group consists of a propyl group bonded to the oxygen atom. When X is
C4 the
alkyloxy group consists of a butyl group bonded to the oxygen atom. When X is
C5 the alkyloxy
group consists of a pentyl group bonded to the oxygen atom. When X is C6 the
alkyloxy group
consists of a hexyl group bonded to the oxygen atom.
"Monoalkyloxy" means that attached to a silicon atom is one alkyloxy group.
"Dialkyloxy" means that attached to a silicon atom are two alkyloxy groups.
"Trialkyloxy" means that attached to a silicon atom are three alkyloxy groups.
5
"Synthetic Liquor" or "Synthetic Spent Liquor" is a laboratory created liquid
used for
experimentation whose composition in respect to alumina, soda, and caustic
corresponds with the
liquor produced by recycling through the Bayer process.
"Bayer Liquor" is actual liquor that has run through a Bayer process in an
industrial
facility.
"Alkylamine" means entities where hydrogen bonds of ammonia are substituted
with
alkyl groups.
"Alkylene" means an unsaturated, aliphatic hydrocarbon with one or more
carbon¨
carbon double bonds.
In the event that the above definitions or a description stated elsewhere in
this application
is inconsistent with a meaning (explicit or implicit) which is commonly used,
in a dictionary,
the application and the claim
terms in particular are understood to be construed according to the definition
or description in
this application, and not according to the common definition, dictionary
definition.
In light of the above, in the event that a term can
only be understood if it is construed by a dictionary, if the term is defined
by the Kirk-Othmer
Encyclopedia of Chemical Technology, 5th Edition, (2005), (Published by Wiley,
John & Sons,
Inc.) this definition shall control how the term is to be defined in the
claims.
In the Bayer process for manufacturing alumina, bauxite ore passes through a
grinding
stage and alumina, together with some impurities including silica, are
dissolved in added liquor.
The mixture then typically passes through a desilication stage where silica is
deliberately
precipitated as DSP to reduce the amount of silica in solution. The slurry is
passed on to a
digestion stage where any remaining reactive silica dissolves, thus again
increasing the
concentration of silica in solution which may subsequently form more DSP as
the process
temperature increases. The liquor is later separated from undissolved solids,
and alumina is
recovered by precipitation as gibbsite. The spent liquor completes its circuit
as it passes through
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a heat exchanger and back into the grinding stage. DSP scale accumulates
throughout the Bayer
process but particularly at the digestion stage and most particularly at or
near the heat exchanger,
where the recycled liquor passes through.
In this invention, it was discovered that dosing of various types of silane-
based products
can reduce the amount of DSP scale formed.
In at least one embodiment of the invention, an effective concentration of a
silane-based
small molecule product is added to some point or stage in the liquor circuit
of the Bayer process,
which minimizes or prevents the accumulation of DSP on vessels or equipment
along the liquor
circuit.
In at least one embodiment, the small molecule comprises the reaction product
between
an amine and at least one amine-reactive silane, the silicon of the silane can
be monoalkyloxy,
dialkyloxy, trialkyloxy or trihydroxy.
In at least one embodiment the small molecule is a reaction product between an
amine-
containing small molecule and an amine-reactive molecule containing at least
one amine-reactive
group per molecule and at least one - Si(OR)11 group per molecule , where n =
1, 2, or 3, and R =
H, Cl -C12 Alkyl, Aryl. Na, K, Li, or NH4, or a mixture of such reaction
products.
In at least one embodiment the method for the reduction of aluminosilicate
containing
scale in a Bayer process comprises the steps of:
adding to the Bayer process stream an aluminosilicate scale inhibiting amount
of a
composition comprising at least one small molecule, the at least one small
molecule comprising
of at least three components, one being an R1 component, one being an R2
component and one
being an R3 component, the components within the small molecule arranged
according to the
general formula:
R2
R1¨N
1R3
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wherein the small molecule may be at least one of: carbonates, bicarbonates.
carbamates, ureas,
amides and salts thereof and:
(i) R1 is selected from the group consisting of: H, alkyl, amine,
alkylamine. structure (A) and structure (B);
OH
(A)
R2
R3
(B)
(ii) .. R2 is independently selected from the group consisting of: H,
alkyl, amine, alkylamine, G and E.
G being one item selected from the group consisting of: 3-
glycidoxyprop yltrimethoxy silane, 3-glycidoxypropyltrialkoxysilane, 3-
glycidoxyprop ylalkyldialkoxysilane,3-glycidoxypropyldialkylmonoalkoxysilane,
3-
isocyanatopropyltrialkoxysilane, 3-isocyanatopropylalkyldialkoxysilane, 3-
isocyanatopropyldialkylmonoalkoxysilane, 3-chloropropyltrialkoxysilane, 3-
chloropropylalkyldialkoxysilane, and 3-chloropropyldialkylmonoalkoxysilane;
E being 2-ethylhexyl glycidyl ether, n-butyl glycidyl ether, t-butyl glycidyl
ether, C3-Cr22
glycidyl ether, C3-C22 isocyanate, C3-C22 chloride, C3-C22 bromide, C3-C22
iodide, C3-C22 sulfate
ester, C3-C22 phenolglycidyl ether, and any combination thereof,
(iii) R3 is independently selected from the group consisting of: H,
alkyl, aminealkylamine, G and E and
(iv) n is an integer from 2 to 6.
In at least one embodiment the R1 is independently selected from the group
consisting of:
monoisopropanol amine, ethylene diamine, diethylene triamine, tetraethylene
pentamine,
i sophoronedi amine, xylenedi amine, bis(aminomethyl)cyclohexane, hexanedi
amine. C,C,C-
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trimethylhexanediamine, methylene bis(aminocyclohexane), saturated fatty
amines, unsaturated
fatty amines such as oleylamine and soyamine, N-fatty-1,3-propanediamine such
as
cocoalkylpropanediamine, oleylpropanediamine, dodecylpropanediamine,
hydrogenized tallow
alkylpropanediamine, and tallow alkylpropanediamine and any combination
thereof.
In at least one embodiment said small molecule is selected from the group
consisting of:
(I), (II), (III), (IV), (V), (VI), (VII), (VIII), and (IX):
0
(OH
HONNH
CY-
HO,
HO I
OH (I)
0
rOH
HO'M
0.,
HO' I OH
OH
(II)
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r'OH
C) rOH
HO ..-
'Si
HO I
OH
(III)
0
C)
HO)
rOH
HO,
Si 0 rOH
HO' I
OH OH 0
(IV)
0
(OH
HOTh
HO,
HO'' I
OH Si,
(V) HO'dmr
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0
re'NOH
i :0H
OH I OH
OH
HO,
HO'- I
OH
(VI)
O
OH
HO'M OH OH
,OH
I OH
OH OH
(VII)
(21.
OH OH
,OH
OH I OH
OH
HO,
Si
HO" IO (VIII)
H
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\.,=Th
O
HO'M OH
OH I OH
OH
HO,
HO''
OH (IX)
In at least one embodiment the small molecule is selected from the group
consisting of:
(X) (XI), (XII), (XIII), (XIV), (XV), (XVI), (XVII), (XVIII), and (XIX):
HO, ...
HO'" I (X)
OH
./'
0
(OH
HONNH
HO ..-
'Si
HO' I
OH (XI)
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0
OH
HO-1
Si,
HO" I OH
OH
(XII)
r-OH
HON- N
HO,
HO I
OH
(XIII)
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HO)
r0H
s, 0 rOH
HO' I
OH OH
."
(XIV)
(OH
HO
HO" I
OH
HO' I OH
OH
(XV)
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OH
o
OH I OH
OH
HO,
HO" I
OH
(XVI)
0.õ
OH OH
I _OH
OH
I 1
OH '0 H
OH
(XVII)
O
HO-Th OH OH
I -OH
OH
OH 61HOH
HO,
i
HO" ISH (XVIII)
O
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0.
HO'M OH
OH I OH
OH
HO,
,
HOSi I
OH (XIX)
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In at least one embodiment the small molecule is selected from the group
consisting of:
(XX), (XXI), and (XXII):
HO
HO-
SI
OH
(XX)
0,- L,OH
0
HO, ...
Si
HO- I
OH _OH
I OH
OH
(XXI)
HOJ
HO, OH
Si 0
HO- I
OH OH
(XXII)
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In at least one embodiment the small molecule is selected from the group
consisting of:
(XXIII), (XXIV), (XXV), (XXVI), (XXVII), (XVIII), and (XDO:
CY-
HO,
Si
HO' 'OH HO-si
HO 'OH
(XXIII)
OH
OH OH
HO,
Si
HO' 'OH
(XXIV)
OH
OH
0
(OH
pH
OH OH
HO,
(XXV)
Ho' OH
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O
HO'M OH
HO N N
OH
O OSOH
/\) OH OH
(XXVI)
OH
HO-si
HO
O
HO-Th OH OH
OH H
OH OH
HO,
SI (0(VII)
HO' 'OH
In at least one embodiment the small molecule is selected from the group
consisting of:
(XXVIII), (XXIX), (XXX), (XXXI), (XXXII) and combinations thereof:
0 HO.1
O
HO
HO-11
OH s1-OH
-
(XXVI II ) HO OH
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N.wõ,,.N H2
pH
OH OH
HO,
Si
HO' 'OH (XXIX)
OH
-OH
OH
r,OH
N NH
pH
OH OH
HO, .
(XXX)
HO 'OH
Th
0Z)
HO
OH
HO N NO
OH
O OSOH
OH OH
(XXXI)
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OH
HO
O
HO'-.1 OH OH
V OOH pH OH
OH OH
HO,Si,-
(Xall)
HO 'OH
In at least one embodiment the small molecule is selected from the group
consisting of:
(XXXIII), (XXXIV), (XXXV), (XXXVI), (XXXVII), (XXXVIII), (XXXIX). (XL), (XLI),
and
(XIII):
0
,
0,
¨0 '0--
(XXXII!)
f
0
r'OH
o/
\
0-11
O (XXXIV)
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0
rµOH
H2N
HO
o
'0
--O
(XXXV)
0
rc,H
HONN
rc,H
0
/
0
0-51
6õ
poavo
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HOõ)
(OH
N
SiO
rOH
000 OH
(XXXVII)
0
(-OH
O HO'M
O
/ O si-c=
0¨
(Xomii)
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(-0H
0
OH
0,
Si
0'
(XXXIX)
O
HO') OH (20"
OH y,o,sP,_--0 /0
OH
(n)
0.õ
HOTh OH
P-
OH
o,
0 b- (XLI)
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O
HC7Y.¨.) OH
OH
0,
-0' 'o-
(XL II)
In at least one embodiment the small molecule is selected from the group
consisting of:
(XLIII), (XLIV), (XLV), (XLVI), (XLVII), (XLVIII), (XLIX), (L), (LI), and
(LII):
N H2
sZr
0 .
'Si (XLI II)
¨0"0¨
r`OH
0
/
0
µ0
0
(XL IV)
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0
OH
HUM
0
0 -s j
0
0
(XLV)
0
('OH
o
o/
0 -Si
(XLVI)
\--=-=""
HOJ
0
H
õ
(3-'Y rOH
OH
(XLVI I)
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O HC:01
/
o-Si
/ 6,, si-o
(XLVIII) 0---
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0
(OH
o'
, OH
0,
Si
so¨ (XLIX)
o
OH HO Th
OH
i
oso /0
OH 0 \
(L)
OH
HO- N N
OH õ,01
0,
Si
0' '0"-- (LI)
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o
He') OH
0-
e
, OH
01,
0 '0- (LII)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LIII), (LIV), and (LV):
0,
Si
0' '0-
\
(LIII)
LOH
HON
01,
-0 b
0
(LIV)
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0
Th's1
OH
0
/0 OH
(LV)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LVI), (LVII), (LVIII), (LIX), (LX), (LI), and (LII):
0
, 0
01,
,S1
0 b-
0
(LVI) 0
O
, OH 0
I
O
1
0,
Si
b- (LVII)
0
0
r-OH
P-
o
1 , OH
().
Si (LVIII)
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O
HO'M OH
o
/\) OH
(LIX)
0\
HO"Th OH
P-
OH
O.
Si (LX)
¨6 b¨
in at least one embodiment the small molecule is selected from the group
consisting of:
(LXI), (LXII), (LXIII), (LXIV) and (LXV):
HO-Th
0,,
/
0--I
/ 6 (LXI) Si-0
0---
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P¨
, OH
0.
SI
(LXI I)
9/
__s -O
o
0
P¨
OH 0
I
0, (LXIII)
Si
Th
HOM OH
HO N N 0
OH
(LXIV)
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u
0\ õ
He') OH
P-
OH
O. .,-
(LXV)
-0 b
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXVI), (LXVII), (LXVIII), (LXIX), (LXX) and (LXXI):
H 0¨
NH OH 0
H2N
(LXVI)
HN
H I
OH
NH2
(LXVII)
NH N
H2N_r
j-NH HO 0-\
H2N \
Si
(LXVIII)
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H2N NH
\_Th
(LXIX)
/ \
H2N-1'-N1-/-1
H2N_/¨NH HO
(LXX)
H2N
HN
H2N
(LXXI)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXXII), (LXXIII), (LXXIV) and (LXXV):
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0, LOH
NMHo 0 b-
H I
HN,1
NH2
(LXXI I)
0, LOH
0
OH 0 0--
N
HN
OH L. NH2
(LXXII I)
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0
0, I /
Si-0
"(20
H
OH 0 0¨
\
HN
H I
rOH NH2
0
(LXXIV)
0
0LOH
L=
OH 0
H I
(L)OW)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXXVI), (LXXVII), (LXXVIII) and (LXXIX):
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0
0,
Si-0
OH
N
OH
0\
(NH
H2N)
(LXXVI)
-0
0
OH OH
/0I0 NH
NN
0\
NH
OH
(LXXVII)
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-0
.,0
0-Si
L=
0
0 H H
0-6
NH
I
H2N HO
(LXXVI I I)
I 0
0. /
Si-0
0
0 0 H H
-õ0
0Si
NH
NH
HN)
HO.)
(L)0(1X)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXXX), (LXXXI), (LXXXII) and (LXXXIII):
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I 0
0, /
Si-0
0
NOH
OH?
NH
H2N) 0H0
Si-0
01 \
(L)00()
\
0
0, /
Si-0
NH
fl
OH?
(NH Ly...,o
H2N OH
P
Si-0
\
(Lxxxo
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I 0
0, /
Si-0
0
L-rNH
0H1)
f.N.,Ho
H2N r---oH H
P
0
-si-0
(Lxxxii)
¨0 ,1
0-si
`c)
0¨
o, ,
0Hr)
0-NNOH
L.,,OHI NH
(L)00(111)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXXXIV), (LXXXV), (LXXXVI) and (LXXXVII):
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-0õ0 OH
OH d
OH
(LXXXIV)
0
0, ,
Si-0
LOH
--0õ0 OH NH
SiO
r*-0H
0
(LXXXV)
\
0
OH
--0õ0 OH NH
SiO
H2N -NH
OH
(LXXXVI)
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I 0
O. /
Si-0
LoH
"CJ4
¨0õ0 OH NH
SiOH0
HN
OH
(L)00(VI I)
In at least one embodiment the small molecule is selected from the group
consisting of:
(LXXXVIII). (LXXXIX) and (XC):
I 0-
0.
Si-0
0
HO)
0
OH b
OH
(LXXXVI I I)
I 0 ¨
0, /
0" OH
N
0 sO
(LXXXIX)
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¨
OH . OH 0 0
HN
LNH
OH
(XC)
In at least one embodiment the small molecule is selected from the group
consisting of: (XCI),
(XCII), (XCIV) and (XCV):
NH OH 0 O¨
f
HN
OH
(xci)
.0
OH 1,4
H2N OH
0
si-0
0"
I /C)
(XCII)
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/ I
0
0-SI i
HCkõ)
HN
NH
H2N OH 0
(XCIII)
/ I
0 \\ ,.,
.l).
011
0
OH HO.,)
0- IO =
HN
0
NH
H2N (xc,v)
0
O.
Si-.0
OH
H 1,1
OH 0 0¨
\
NH
H2N (xcv)
In at least one embodiment the small molecule is selected from the group
consisting of: (XCVI),
(XCVII) and (XCVIII):
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H OH
NH OH OH
H2N
(XCVI)
HHN
I
OH
(:).T -OH
OH OH
NH2
(XCVII)
NH N
/
\ ,OH
Si
HO 'OH
(XCVIII)
In at least one embodiment the small molecule is selected from the group
consisting of: (XCIX),
(C), (CI) and (CII):
OH
SI-OHO,
H
LOH
yos., HO
n10. HO OH
HN,1
(NH2
(XCIX)
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HO, OH
LOH
OH HO' 'OH
HNN
H I
rOH NH2
0
(C)
HO, OHSOH
L.OH
OH HO' 'OH
OH L.NH2
(CI)
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HO OH
õ2,
Si-OH
LOH
OH HO 'OH
tOs
H I
(CII)
In at least one embodiment the small molecule is selected from the group
consisting of: (CIII),
(CIV), (CV) and (CVI):
HO OH
Si 0H
0
OH OHLOH
OH
H0 OLj
rNH
H2N
(CIII)
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HO
.0H
HO-01 i
L 0H 1,2,4
OH OH
H 0- NH
HO
I
H2N
0,,
==,õ,
(C IV)
HO .0H
HO-1
OH OH OH
NH
HO
r NH
H2N OH
(CV)
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HO, OHI
(1)
HO OH OHLOH
õ
HOSiO
NH
NH
HN
HO)
(CVO
In at least one embodiment the small molecule is selected from the group
consisting of: (CVII),
(CVIII), (CIX) and (CX):
OH
T-OH
N OH
OHH
j
f-NH
H2N OH
OH
OH
(CVII)
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H
HO O
,,/
OH
NH
OH rl
N NH
Y'Co
H2N rOH H L=
OH
OH
(CXII)
H
HO O
, /
L'r NH
OH r,J ,(n
N OH
r. N H
H2N OH
OH
OH
(C IX)
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HO
,OH
HO-11
OH
T-OH
0Hrl
LOHINH
(CX)
In at least one embodiment the small molecule is selected from the group
consisting of: (CXI),
(CXII), (CXIII) and (CXIV):
HOõOH OH
OH
OH H
OH
(CXI)
HO
,OH
HO-Si
LOH
SiO
HOõOH OH
L.)
H2N
OH
(CXII)
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HO OH
,
11-0H
LOH
HO õOH OH NH
HO-Si*C)**1
L.)
H2N
H
0
(CXII I)
HO.. ,õ
T-OH
LOH
HO 9H OH NH
H 0,S i
HN
OH
(CXIV)
In at least one embodiment the small molecule is selected from the group
consisting of: (CXV),
(CXVI) and (CXVII):
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OH
HO, /
HO)
,OH
OH
HO 'OH
OH
(CXV)
HO, OHSI -OH
OH
H0,.)
OH HO 'OH
(CXVI)
OH L,1 OH HO OH
HN,1
IN.
NH
HO' 'OH OH
(CXVII)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXVIII), (CXIX), (CXX) , (CXXI) and (CXXII):
NH OH HO OH
HN
OH
OH OH
(CXVIII)
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,OH
OH
OH
OH
X OH
H2N
,Si,
HO OH
OH
(CXIX)
HO
õOH
0
HON)
HN
H
NH pH
H2N OH OH
(CXX)
HO
c,µ :,OH
13
OH OH HO)
HO HN
NH
H2N
(cxxo
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HO, PH
OH
LOH
_OH
OH HO OH
r,NH
H2N.J (CXXII)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXXIII). (CXXIV) and (CXXV):
H2N-f \-NH
HO 0 (
(00(111)
H2N
/-NH HO 0 (
H2N-1
(CXXIV)
H2N
HN-
HN
___________________________________________ \o (
H2N
(CXXV)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXXVI), (CXXVII), (CXXVIII) and (CXXIX):
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\
0, /
SLOH
i -0
0
N s
o OH
OH 0' 0-
\
HN
H
NH2
(C)0(Vi
\o
0, /
Si-0
LOH
OH 0
HN
rOH NH2
(CXXVI I)
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0
0,
Si-0
L.OH
OH 0 0-
\
HN N
HN
OH
NH2
(CXXVi
0
0'.Si-0
LOH
OHHNN
0 0-
\
HN HO)
H I
(CXXIX)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXXX), (CXXXI), (CXXXII) and (CXXXIII):
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0
O.
Si-0
OH
OH
/0-s i0_)
N
0\ `03
(NH
H2N)
(CX)0()
-0
0-Si
OH OH
0-Si NH
0\
I
H2N HO-1
(CXXXI)
-0
..0
OH [=.,,OH
0- IO =
NH
0
(NH L.OH
H2N)
(CXXXII)
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I 0
0
0 0 H H
¨õ0
NH
NH
HN
H
0
(000(110
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXXXIV), (CXXXV), (CXXXVI) and (CXXXVII):
I 0
0, /
N H
OH?
I NH HO
H2N OH
P
\
(cxxxiv)
59
09
(iAxxx3)
(3-!sõ,
HO NH
HN
O HO
HN
0 1
(AXXXO)
0--!L
HoH I NH
rj HO
HN
'0
0 1
66ZLZO/10ZSI1LE.3.1 899Z1/10Z
OM
LO-LO-VTOU 08098Z0 VD
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-0 I
..0
0-Si
0
0¨
0
OH ri ,..0
0-
NH
I
(CX)00/11)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXXXVIII), (CXXXIX), (CXL) and (CXLI):
\
¨0
NH2
NH
H N N
>=(:)..-y OH 0 0¨
\
OH
(C)OCXVI I I)
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\ .,0
LOH
011
0
--0õ0 OH NH
L.)
OH
(CXXXIX)
I 0
0, /
LOH
--0õ0 OH NH
OH
(CXL)
\o
SI-0
OH
-0õ0 OH NH
iO
0,S
HN
>C3.f)
OH
(CXLI)
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In at least one embodiment the small molecule is selected from the group
consisting of: (CXLII),
(CXLIII) and (CXLIV):
NH
e
HN
0, NH
Si
0"0
/
HN
0 b--
>,ey OH
OH
(CXLI I)
I 0 -
0.
Si-0
O OH
HO.)
N
0 \
(CXLIII)
'
H OH 00
HN
N 1,5,3
H
b OH
(CXLIV)
In at least one embodiment the small molecule is selected from the group
consisting of: (CXLV),
(CXLVI), (CXLVII) and (CXLVIII):
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HO, OH/
Si I-OH
LOH
0 OH HO 'OH
H N
N H2
(CXLV)
H
HO, / O
11-OH
LOH
HNN
OH HO' OH
H I
rOH NH2
(CXLVI)
H
HO, / O
0
LOH
N i H
r.) OH HO' 'OH
>,o,y HN.N1
OH N H2
(CXLVII)
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HO OH,
OH
LOH
(OH
OH HO' 'OH
HN HO)
H I
(CXLVI II)
In at least one embodiment the small molecule is selected from the group
consisting of:
(CXLIX), (CL), (CLI) and (CLII):
HO OH
r OH
OH OHLOH
HO-gi
HO
NH
H2N- (GXL IX)
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HO
,µ õOH
HO-91
O OH H
OH
HO-0
HO
I '
H2N HO'M
(CL)
HO
HO- Si
O OH H
OH
H 0-
NH
H0
NH
H2N 0Z)
(CLI)
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H
HO, , O
OH
0
H0õ0
OHLOH
NH
NH
HN
(CLII)
In at least one embodiment the small molecule is selected from the group
consisting of: (CLIIII),
(CLIV), (CLV) and (CLVI):
HO, PH/
N OH
0Hrl
NH Ho
L.,
H2N OH
OH
T-OH
OH
(CLIII)
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OH
HO,
Si-OH
NH
OH ri
N NH
IN
H2N role
OH
OH
(CLIV)
OH
HO,
i-OH
0
NH
OH)
IN H Ho
H2N OH
OH
OH
(CLV)
HO
;.õ .0H
HO-11
OH
HO,
i -OH N H
OH? 0
CY-
N
1OH (NH
)
(CLVI)
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In at least one embodiment the small molecule is selected from the group
consisting of: (CLVII),
(CLVIII), (CLIX) and (CLX):
OH
HO-
HO
NH2
H
HON
NH
OH HO' OH
OH
(CLVII)
HO
_OH
OH
HO, OH OH NH
HOSIO
H2N
NNNH
Y'e*<
OH
(CLVIII)
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HO OH
T-OH
LOH
HO õOH OH NH
H 0-S i
/70H
(CL IX)
HO, OH
õ
011-0H
0
LOH
HO pH OH NH
H 0,S i
OH
(CLX)
In at least one embodiment the small molecule is selected from the group
consisting of: (CLXI),
(CLXII), and (CLXIII):
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NH
HN,)
HO, LNH
HO' OH
L.)
OH HO 'OH
OH
(CLXI)
HO, OH
i-OH
0 OH
HO,,)
NH
O
OH
(CLXII)
N N N _OH
OH LI OH HOOH
HN
LNH
HOssio*
HO' 'OH OH
(CLXI II)
In at least one embodiment the small molecule is present in a solution in an
amount ranging from
about 0.01 to about 100 wt%. The composition may further comprise one item
selected from the
list consisting of: amines, activators, antifoaming agents, co-absorbents,
corrosion inhibitors,
coloring agents, and any combination thereof. The composition may comprise a
solvent, the
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solvent is selected from the group consisting of: water, alcohols, polyols,
other industrial
solvents, organic solvents, and any combination thereof. The components may be
isolated from
the reaction in the form of a solid, precipitate, salt and/or crystalline
material in pH's ranging
from 0 to 14.
Although some of these small molecules have been mentioned in various
references, their
uses are for entirely unrelated applications and their effectiveness in
reducing Bayer Process
scale was wholly unexpected. Some places where these or similar small
molecules have been
mentioned include: US Patent 6,551,515, scientific papers: Ethylenediamine
attached to silica as
an efficient, reusable nanocatalyst for the addition of nitromethane to
cyclopentenone, By
DeOliveira, Edimar; Prado, Alexandre G. S., Journal of Molecular Catalysis
(2007), 271(1-
2), 6369, Interaction of divalent copper with two diaminealkyl hexagonal
mesoporous silicas
evaluated by adsorption and thermochemical data, By Sales, Jose; Prado,
Alexandre; and
Airoldi, Claudio, Surface Science, Volume 590, Issue 1. pp. 51-62 (2005), and
Epoxide silyant
agent ethylenediamine reaction product anchored on silica gel-thermodynamics
of cation-
nitrogen interaction at solid/liquid interface, Journal of Noncrystaline
Solids, Volume 330, Issue
1-3, pp. 142-149 (2003), international patent applications: WO 2003002057 A2,
WO
2002085486, WO 2009056778 A2 and WO 2009056778 A3, French Patents: 2922760 Al
and
2922760 B1, European Patent: 2214632 A2, and Chinese patent application: CN
101747361.
The effectiveness of these small molecules was unexpected as the prior art
teaches that
.. only high molecular weight polymers are effective. Polymer effectiveness
was presumed to
depend on their hydrophobic nature and their size. This was confirmed by the
fact that cross-
linked polymers are even more effective than single chain polymers. As a
result it was assumed
that small molecules only serve as building blocks for these polymers and are
not effective in
their own right. (WO 2008/045677 [0030]). Furthermore, the scientific
literature states "small
molecules containing" ... "[an] Si-03 grouping are not effective in preventing
sodalite
scaling".... because ... "[t]he bulky group" ... "is essential [M] keeping the
molecule from being
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incorporated into the growing sodalite." Max H7114 Sodalite Scale Inhibitor:
Plant Experience
and Impact on the Process, by Donald Spitzer et. al., Page 57, Light Metals
2008. (2008).
However it has recently been discovered that in fact, as further explained in
the provided
examples, small molecules such as those described herein are actually
effective at reducing DSP
scale.
It is believed that there are at least three advantages to using a small
molecule-based
inhibitor as opposed to a polymeric inhibitor with multiple repeating units of
silane and
hydrophobes. A first advantage is that the smaller molecular weight of the
product means that
there are a larger number of active, inhibiting moieties available around the
DSP seed crystal
sites at the DSP formation stage. A second advantage is that the lower
molecular weight allows
for an increased rate of diffusion of the inhibitor, which in turn favors fast
attachment of the
inhibitor molecules onto DSP seed crystals. A third advantage is that the
lower molecular weight
avoids high product viscosity and so makes handling and injection into the
Bayer process stream
more convenient and effective.
The invention further relates to the synthesis of new small molecule chemical
entities that
show surprisingly improved performance for the inhibition of DSP scale in
Bayer liquor
compared to those previously disclosed. In this work, the extension of the
diamine structure by
increasing the number of reactive nitrogen groups to between 3 to 5 with
spacing by one, two or
three alkylene groups (e.g., ethylene or propylene) as indicated by the
general structure below,
has resulted in remarkably improved rates of adsorption of the inhibitor onto
DSP seed surfaces
as well as DSP scale inhibition performance over earlier compositions, for
example those based
on hexane diamine, ethylene diamine and 1-amino-2-propanol.
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NH2
H2
H2
H2N
c/R'xcNH2
H2
where R' = CH2, or, CH2-CH2; and X -= NH2, NH2-R'-NH2, or NH2-R'-NH2-R'-
NH2
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Thus, the following readily available amine compounds (A) (from Sigma-
Aldrich), can be
used:
= N1-(2-aminoethyl)ethane-1,2-diamine, commonly known as
diethylenetriamine,
(DETA),
= N1-(3-aminopropyl)propane-1,3-diamine, commonly known as
dipropylenetriamine, (DPTA),
= N1,Nr-(ethane-1,2-diy1)bis(ethane-1,2-diamine), commonly known as
triethylenetetramine, (TETA),
= N1,Nr-(propane-1,3-diy1)bis(propane-1,3-diamine), commonly known as
triproylenetetramine, (TPTA),
= N1-(2-aminoethyl)-N2-(242-aminoethyl)amino)ethyl)ethane-1,2-diamine,
commonly known as tetraethylenepentamine, (TEPA).
The preferred synthesis for the formation of these new A:G:E chemical entities
involves
the reaction of the amine with component G first (in an amount ranging between
1.0-2.5 mole
ratio to amine) followed by the reaction with component E (in an amount
ranging between 0.5-
2.0 mole ratio to amine) in a semi-batch method.
A preferred A:G:E compositions range, in general, having mole ratios of
between:
= About 1.0: 1.0: 0.5 to about 1.0: 3.0 : 2.0 A: G : E
and more preferred compositions with mole ratio of:
= About 1.0: 1.0: 0.5 to about 1.0 : 2.0: 1.0 A: G: E
and most preferred are compositions with mole ratio of:
= About 1.0 : 2.0 : 0.8 A : G : E.
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The improved DSP scale inhibition performance for these compositions over
early small
molecules are surprising from the following aspects:
1. The A:G:E complexes or adducts have low molecular weights (<1000 g/mole)
compared to
the silane substituted highly polymeric structures based on polyacrylate
acrylamide
copolymers or polyethyleninimine polymers disclosed in the prior art, and,
more specifically
including the chemistries disclosed as examples in the Cytec patent
application WO/045677
Al involving silane substituted polyamines or amine mixtures that have been
extensively
cross-linked using epichlorohydrin.
.. 2. The small molecule silane containing A:G:E complexes (or adducts) have a
unique structure
compared to the 0.5 mole % silane substituted polymers disclosed in the prior
art. The
preferred order of addition of the component G followed by the component E
leads to a more
preferred spatial arrangement or distribution of the silane group with respect
to the more
hydrophobic E group in the small molecule, compared to a totally random
distribution of G
and E that would be anticipated from in a true batch reaction.
It should be noted that an obvious extension of this invention is that
combinations of
A:G:E compositions can also be added as mixtures as an inhibiting amount for
reduction of
aluminosilicate scale.
In at least one embodiment these small molecules can be isolated as the
unhydrolized
alkoxysilane, protected with methyl or ethyl ether groups. These compounds can
be sold and
transported to the customer site as a dry granular product instead of as a
caustic solution (liquid).
This can provide the following benefits over exiting scale inhibitors:
= Lower transportation costs and delivery of high actives products
76
= Significantly lower environmental and human exposure hazards during
manufacture,
transportation and handling due to non-hazardous solid gel compared to a
potentially
corrosive caustic solution.
These compounds can be hydrolyized on-site at a 0.01-50 % concentration, more
preferably between 0.01 ¨25 % and most preferably between 0.1 ¨ 10 %
concentration in a
caustic solution containing between 5-100 gpL sodium hydroxide and more
preferably between 5
¨ 50 g/L and most preferably in a caustic solution containing between 5-25 gpL
sodium
hydroxide, or they can be hydrolyzed directly in-situ in the Bayer process, in
either case,
hydrolysis of the alkyl ether on the silane occurs to form the - corresponding
hydroxysilane
compound(s) with ¨Si-(OH)3 groups which are readily soluble in the caustic and
Bayer solutions.
In at least one embodiment a further improvement in scale inhibition
performance is
achieved using A:G:E compositions synthesized as described above and further
treating the
resulting mixture of compounds with a very small amount of an di-oxirane
coupling agent,
available from CVC Thermoset Specialties, having a general structure of:
H2c
1)0
HC
112C
\o
o+tn
H2c
I"
where n = 1, 2, 4, 6
such as:
= Ethylene glycol di glycidyl ether (EGDGE),
= 1,4-butanediol diglyicidyl ether
= 1,6-hexandiol digylicdyl ether,
= propylene glycol digylcidyl ether.
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Post addition of between about 0.2 to about 0.5 mole % of the coupling agent
is expect to
form portions of a dimer having the general structure:
[A:G:E] 2 : X
Trace amounts of extended adduct, for example, trimeric species, tetrameric,
etc.,
compounds might also be formed in the process however, addition of too much of
the di-oxirane
coupling agent results solids that are not readily soluble in caustic
solution. It is important that
the composition be readily soluble in caustic to ensure successful application
in the Bayer
process liquor.
The preferred A:G:E:X compositions range, in general, having mole ratios of
between:
= About 1.0 : 1.0 : 0.5 : 0.2 to about 1.0 : 2.5 : 2.0 : 0.5 A:G:E:X
and more preferred are compositions with mole ratio of between:
= About 1.0 : 1.5 : 0.5 : 0.25 to about 1.0 : 2.0 : 1.0 : 0.5 A:G:E:X
and even more preferred are compositions with mole ratio of between
= About 1.0 : 2.0 : 0.8 : 0.25 to about 1.0 : 2.0 : 0.5 : 0.5
and most preferred are compositions with mole ratio of about:
= 1.0 : 2.0 : 0.8 : 0.25 A : G : E : X.
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Below is a schematic of at least one possible compound, where R independently
represents H, alkyl, alkylamine, inorganic and organic species such as salts,
ethers, anhydrides
etc. in the possible mixture of small molecules that are formed in these
reactions.
R ¨0
0
R/
OH
H N
HOO
OH
NH
HN
o0 H N
OH
NH2
o
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In at least one embodiment these small molecules can be isolated as the
unhydrolized
alkoxysilane, protected with methyl or ethyl ether groups. These compounds can
be sold and
transported to the customer site as a dry granular product instead of as a
caustic liquid solution.
This can provide the following benefits over exiting scale inhibitors:
= Lower transportation costs and delivery of high actives products
= Significantly lower environmental and human exposure hazards during
manufacture, transportation and handling due to non-hazardous solid gel
compared to a potentially corrosive caustic solution.
These compounds can be hydrolyzed on-site at a 0.01-50.0% concentration, more
preferably between 0.01 ¨25 % and most preferably between 0.1 ¨ 10%
concentration in a
caustic solution containing between 5-100 gpL sodium hydroxide and more
preferably between
5 ¨ 50 g/L and most preferably in a caustic solution containing between 5-25
g/L sodium
hydroxide , or they can be hydrolyzed directly in-situ in the Bayer process,
in either case,
hydrolysis of the alkyl ether on the silane occurs to form the now soluble
hydroxysilane
.. compound(s) with ¨Si-(OH)3 groups.
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EXAMPLES
The foregoing may be better understood by reference to the following examples,
which
are presented for purposes of illustration and are not intended to limit the
scope of the invention.
I. Example of a Synthesis Reaction A, E and G.
In a typical synthesis reaction the three constituents: A (e.g., hexane
diamine), G (e.g. 3-
glycidoxypropyltrimethoxysilane) and E (e.g. ethyl hexyl glycidyl ether) are
added to a suitable
reaction vessel at a temperature between 23-40 'C and allowed to mix. The
reaction vessel is
then warmed to 65-70 C during which time the reaction begins and a large
exotherm is
generated. The reaction becomes self-sustaining and depending on the scale of
the reaction, can
reach temperatures as high as 125 to 180 C. Typically the reaction is complete
after 1 to 2 hours
and then the mixture is allowed to cool down. As an aspect of this invention
this un-hydrolyzed
product mixture can be isolated as a liquid or gel or a solid in a suitable
manner. Alternatively,
the reaction product mixture can be hydrolyzed, via a number of methods, to
prepare a solution
of the hydrolyzed product mixture in water. The hydrolysis of the alkoxysilane
groups in the
component G results in the formation of the corresponding alcohol (e.g
methanol, ethanol etc.,
depending on the akloxysilane used in the synthesis).
It is common to those skilled in the art to conduct the ring opening of an
epoxide with a
reactive amine in a batch mode (where the components are mixed together),
heated to an
initiation temperature above room temperature (e.g. 50-65 C) with the
reaction temperatures
allowed to reach as high as 125 to 180 'C. This can cause internal cross-
linking and side reactions
to occur ¨ which is often desired in the resin manufacturing processes.
However, at least one embodiment involves the use of a continuous or semi-
batch
synthesis method which provides several advantages over the batch process
commonly used.
This involves adding only a portion of the G and E constituents either
together or sequentially or
individually in a form of a slow feed to initiate the primary epoxide ring
opening reaction,
followed by the slow continuous feeding of the two constituents G and E
(either together or
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separately and at the same time or sequentially). This method allows for a
much better control
over the overall reaction, the reaction temperature and provides a better
overall yield of the active
compounds in the product also avoiding the undesired side reactions.
in at least one embodiment the synthesis reaction utilizes constituent G = 3-
glycidoxypropyltrimethoxysilane. Prolonged exposure at high temperatures above
120 C can
result in internal coupling reactions and multiple substitutions with the
reactive amine groups
such as hexane diamine or ethylene diamine. The resulting un-hydrolyzed
reaction products will
turn to a gel over shorter time period accompanied by an increase in the
reaction product
viscosity. Use of a semi¨batch process or continuous or separate or slow
sequential or individual
or combined feed of the E and G epoxides into the reaction mixture allows
better control of the
reaction temperature thereby reducing the amount of methanol that is generated
and isolated
during the reaction. Furthermore the reaction mixture has a lower viscosity
and accounts for
fewer undesired side reactions (see Table 1).
Table I: Synthesis Reaction Data for A:G:E reactions by various methods
Reaction Viscosity of
Batch Me0H
Method Temp Reaction
Isolated, lbs
Intermediate, cps
1 Batch 240-265 550 9.8
2 Batch on Batch 225-235 240 1.6
3 Semi-Batch 180-200 65 0.7
Examples of the relative DSP scale inhibition of various A:G:E small molecules
formed
during the synthesis reaction disclosed above.
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The scale inhibition performance of the small molecule is typically performed
as follows:
1) A small amount of sodium silicate (0.25 ¨ 1.5 g/L as SiO2) is added to a
Bayer refinery
spent liquor at room temperature to raise the silica concentration in the
liquor.
2) Portions of this liquor sample are dosed with varying amounts of the new
scale inhibitor
compound or mixture.
3) Dosed and untreated (or Blank) liquor samples are subjected to elevated
temperatures
between 96 to 105 t for 4 to 6 hours.
4) Samples are then cooled and the amount of DSP scale formed in each of the
dosed liquors
samples are measured and compared to that formed in the untreated or blank
samples.
.. As an example, Table 2 shows the relative DSP Scale Inhibition for several
A:G:E synthesized
mixtures using the synthesis reaction disclosed earlier, with various amine
constituents as the
core.
Table 2. Relative DSP Scale Inhibition for Various A:G:E Synthesized Reaction
Mixtures, where
A = Amine
G = Glycidoxypropyltrimethoxysilane
E = 2-Ethylhexyl glycidyl ether
% Reduction in DSP
Amount of DSP Scale mg,
A:G:E Compounds Scale
versus Treatment
versus Blank
A = Amine Used Untreated Low Dose High Dose Low Dose High
Dose
IIexane Diamine 26.20 0.18 0.06 99.3% 99.8%
Ethylene Diamine 27.30 20.40 8.12 25.3% 70.3%
Diethylene Triamine 26.70 18.30 10.27 31.5% 61.5%
Tetraethylene pentaamine 24.60 22.50 16.80 8.5% 31.7%
1- amino- 2-propanol 26.20 3.50 0.05 86.6% 99.8%
As an example but not limiting the scope of this invention, is the synthesis
and improved DSP
scale inhibition performance for a series of new TEPA:G:E and TEPA:G:E:EGDGE
adduct
compositions examples of which are given in Table 3 below..
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Table 3: New Amine:G:E chemistries and [Amine:G:E]2-X adducts as DSP Scale
Inhibitors
Mole Ratio Mole Ratio Mole Ratio Mole
Ratio
Sample 1D Amine
Amine G E EGDGE
1 HMDA 1 1 0.8 0
2 M1PA 1 1 0.8 0
A TEPA 1 1 1.0 0
B TEPA 1 1 1.0 0.25
C TEPA 1 2 0.8 0
D TEPA 1 2 0.8 0.25
E TEPA 1 2 0.8 0.5
F TEPA 1 2 0.5 0.5
G TEPA 1 3 0.8 0
H TEPA 1 3 0.8 0.25
1 TEPA 1 2 0.5 0
J TEPA 1 2 0.5 0.25
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Table 4 shows the % decrease in net DSP scale for the 1.0 : 2.0: 0.8 mole
ratio TEPA:G:E
chemistry (sample C) and corresponding coupled adduct with 0.25 mole ratio
EGDGE (sample
D) and over the 1.0: 1.0: 0.8 mole ratio HDA:G:E C compositions (sample 1)
disclosed
previously.
Table 4: Efficacy results as related to decrease in net DSP
Decrease
Dose Avg. Net DSP,
Sample Mass 1, g Mass 2, g Std. D. in Net
ppm DSP, g
DSP
Control 0.3220 0.3312 0.3266 0.0046 0.3266
Control DSP 0 0.5199 0.4939 0.5119 0.0127 0.4119 0
1 30 0.4015 0.3933 0.3974 0.0041 0.2974
27.9%
30 0.3091 0.3148 0.3120 0.0028 0.2120
48.5%
40 0.2706 0.2822 0.2764 0.0058 0.1764
57.2 %
60 0.2399 0.2416 0.2408 0.0009 0.1408
65.8%
30 0.2226 0.2215 0.2221 0.0006 0.1221
70.4%
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Table 5 shows how the adsorption rate of the new 1.0:2.0:0.8 mole ratio
TEPA:G:E composition
(sample C) applied at a constant dose over various contact times with DSP seed
crystals is
significantly faster than that found for the previously disclosed 1.0:1.0:0.8
mole ratio
HMDA:G:E (sample 1) scale inhibitor.
Table 5: Efficacy results versus time at a constant dosage of inhibitor
Contact
Avg. Net DSP, Decrease in
Sample Time, Mass 1, g Mass 2, g Std. D.
DSP, g g Net DSP
min.
Control 0.0462 0.0619 0.0541 0.0079 0.0541
Control DSP - 0.3090 0.3041 0.3284 0.0310 0.1284 0
2 0.2984 0.3010 0.2997 0.0013 0.0997 22.3
%
5 0.2595 0.2746 0.2671 0.0075 0.0671
47.7%
8 0.2415 0.2528 0.2472 0.0057 0.0472
63.2%
1 2 0.3166 0.3200 0.3183 0.0017 0.1183 7.9%
1 5 0.2944 0.2795 0.2870 0.0074 0.0870
32.2%
1 8 0.2627 0.2764 0.2696 0.0069 0.0696
45.8%
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Table 6 shows the continuous reduction in net DSP scale formation as a
function of the dosage
applied of the small molecule sample C from 0 to 80 ppm as product. Complete
scale inhibition
was found at dosages above 80 ppm.
Table 6: Complete inhibition of DSP by sample C
Dose, Mass 1, Mass 2, Mass 3, Avg. %DSP
Std. D.
ppm g g g DSP, g Precipitated
0
0.2904 0.2754 0.2798 0.2819 0.0063 100.0
Control
20 0.1330 0.1479 0.1405 0.0075 49.8
30 0.0663 0.0924 0.0794 0.0131 28.2
40 0.0219 0.0270 0.0245 0.026 8.7
60 0.0075 0.0042 0.0059 0.0017 2.1
80 0.0000 0.0000 0.0000 0.0000 0.0
As an example but not limiting the scope of this invention, is the synthesis
and improved
DSP inhibition performance for the 1.0 : 2.0: 0.8 : 0.25 mole ratio
TEPA:G:E:EGDGE coupled
adduct (sample D) over the performance for the 1.0 : 2.0: 0.8 mole ratio
TEPA:G:E uncoupled
chemsitry (sample C) and 1.0:1.0:0.8 HMDA:G:E (sample 1).
Table 4 provided some data for the improved performance of the coupled adduct
sample
D over sample C. As a further example, Table 7 shows how the performance for
the coupled
adducts, as given in Table 3, having 1 to 2 mole ratio of alkoxysilane groups
(G) provides better
scale inhibition than the uncoupled TEPA:G:E chemistries and 1.0:1.0:0.8
HMDA:G:E
(sample 1).
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Table 7: Enhanced efficacy for the coupled adducts as related to a decrease in
net DSP
Decrease
Mass 1, Mass 2, Mass 3, Avg. Net DSP,
Sample Std. D. in
Net
DSP, g
DSP
Control 0.0575 0.0785 0.0680 0.0105 0.0680
Control
0.3240 0.3388 0.3778 0.3469 0.0227 0.1469 0
DSP
1 0.3370 0.3190 0.3280 0.0090 0.1280
12.9%
A 0.2726 0.2831 0.2779 0.0053 0.0779
47.0%
0.2493 0.2587 0.2540 0.0047 0.0540
63.2%
0.2701 0.2828 0.2765 0.0063 0.0765
47.9%
0.2382 0.2336 0.2359 0.0023 0.0359
75.6%
0.3145 0.3454 0.3300 0.0155 0.1300
11.5%
0.3064 0.3192 0.3128 0.0064 0.1128
23.2%
For example, compare the performance of
= sample B versus sample A, and,
= sample D versus sample C, and,
= sample H versus sample G.
Furthermore, the results from Table 7 indicate that the preferred composition
is 2 moles
equivalents of alkoxysilane groups G based on the amine compared to 1 mole
equivalent of
alkoxysilane group G for either the uncoupled or coupled small molecules, for
example compare
the results for sample C with sample A and sample D with sample B.
Surprisingly, increasing the level of alkoxysilane groups G to greater than
two, e.g., three,
mole equivalents does not lead to a further enhancement in the DSP scale
inhibition performance
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in contrast to what might be expected. In fact the addition of three
equivalents leads to a lower
performance than for compounds with only one equivalent of alkoxysilane group
G.
Evidence for this is in Table 7, compare the performance of
= the uncoupled sample G versus samples C and A, and,
= EGDGE coupled sample H versus samples D and B
Thus, it is postulated that it is not only the presence of the silane that is
key to ensure
binding of the inhibitor to the DSP seed or nuclei to prevent further growth
of the crystal. It is
possible that the presence of unhindered amine sites also helps to improve
adsorption and scale
inhibition. A spatial separation of the silane was achieved in previously
disclosed HDA:G:E
compounds. The unhindered amine may help to facilitate improved binding of the
small
molecule to the DSP seed crystal.
Evidence for this is the observed relative differences in the rate of
adsorption between
these chemistries onto the DSP seed crystals. As an example, Table 8 shows
that the new
1.0:2.0:0.8:0.25 mole ratio TEPA:G:E:EGDGE composition (sample D) adsorbs
significantly
.. faster to the surface of a DSP seed crystal compared to the 1.0:1.0:0.8
mole ratio HDA:G:E)
composition (sample 1).
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Table 8: Faster adsorption of coupled adducts versus uncoupled chemistries.
Contact
Decrease
Time, Mass 1, Mass 2, Mass 3, Avg. Net in Net
Sample mm g g g DSP, g Std. D. DSP, g DSP
Control 0.0427 0.0445 0.0436 0.0009 0.0436
ContDSP 0.3101 0.3033 0.3569 0.3234 0.0238 0.1234 0
2 0.2922 0.2895 0.2909 0.0013 0.0908 26.4%
5 0.2527 0.2641 0.2584 0.0057 0.0584 52.9%
8 0.2219 0.2261 0.2240 0.0021 0.0240 83.5%
1 2 0.3167 0.3136 0.3152 0.0016 0.1152 6.6%
1 5 0.3091 0.2871 0.2981 0.0110 0.0981 20.5%
1 8 0.3000 0.3106 0.3053 0.0053 0.1053 14.7%
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Table 9 shows the continuous reduction and complete elimination of DSP scale
formation
as a function of the applied dosage of the sample D from 0 to 80 ppm as
product. Further
supporting the improvement over the uncoupled composition complete scale
inhibition was
found at dosages between 50-60 ppm compared to 80 ppm for sample C (see Table
4).
Table 9: Complete inhibition of DSP by sample D
Dose, Avg. Mass %DSP
ppm DSP, g Precipitated
0
0.4540 100.0%
Control
20 0.3015 66.4%
30 0.1850 40.7%
40 0.0585 12.9%
60 0.0000 0.0%
80 0.0000 0.0%
Tables 10 and 11 provided additional examples of improved performance of the
coupled A:G:E
adducts over uncoupled A:G:E compositions, for example compare the results for
samples E, F,
H and J against the corresponding uncoupled samples C, 1, G, and sample 1
(from table 3).
Additionally these samples show how the relative scale inhibition performance
is influenced by
subtle changes in the mole ratio of components E and di-oxirane coupling agent
in the
compositions. The results indicate that for the uncoupled compositions the
preferred amount of
the E component is about 0.8 mole ratio. However, for compositions with the
coupling agent
EGDGE, scale inhibition improves with a slight decrease in component E from
about 0.8 to
about 0.5 mole ratio when the EGDGE component is increased from a mole ratio
of about 0.25 to
0.5.
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Table 10: Advantages of coupled [Amine:G:E]2-X adducts versus uncoupled
Amine:G:E
chemistries as related to net DSP
Decrease
Mass 1, Mass 2, Mass 3, Avg. Net DSP,
Sample Std. D. in
Net
DSP, g
DSP
Control 0.0351 0.0323 0.0337 0.0014 0.0337
Control 0.2958 0
DSP 0.3093 0.3079 0.3043 0.0061 0.1043
0.2932 0.2898 0.2915 0.0017 0.0915
12.3%
0.2544 0.2466 0.2505 0.0039 0.0505
51.6%
0.2133 0.2158 0.2146 0.0013 0.0146
86.1%
0.2553 0.2634 0.2594 0.0040 0.0594
43.1%
0.2276 0.2260 0.2268 0.0008 0.0268
74.3%
0.2133 0.2081 0.2107 0.0026 0.0107
89.7%
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Table 11: Advantages of coupled [Amine:G:E]2-X adducts versus uncoupled
Amine:G:E
chemistries; Additional Examples
Decrease
Mass 1, Mass 2, Mass 3, Avg. Net DSP,
Sample Std. D. in
Net
DSP, g
DSP
Control 0.0352 0.0361 0.0357 0.0005 0.0357
Control
0.3214 0.3291 0.3269 0.3258 0.0032 0.1258 0
DSP
0.2132 0.2152 0.2142 0.0010 0.0142
88.7%
0.2288 0.2345 0.2317 0.0029 0.0317
74.8%
0.2421 0.2338 0.2380 0.0042 0.0380
69.8%
0.2213 0.2270 0.2242 0.0029 0.0241
80.8%
While this invention may be embodied in many different forms, there are shown
in the
drawings and described in detail herein specific preferred embodiments of the
invention. The
present disclosure is an exemplification of the principles of the invention
and is not intended to
limit the invention to the particular embodiments illustrated.
Furthermore, the invention encompasses any possible combination of
some or all of the various embodiments described herein and incorporated
herein.
The above disclosure is intended to be illustrative and not exhaustive. This
description
will suggest many variations and alternatives to one of ordinary skill in this
art. All these
alternatives and variations are intended to be included within the scope of
the claims where the
term "comprising" means "including, but not limited to". Those familiar with
the art may
recognize other equivalents to the specific embodiments described herein which
equivalents are
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also intended to be encompassed by the claims.
All ranges and parameters disclosed herein are understood to encompass any and
all sub-
ranges assumed and subsumed therein, and every number between the endpoints.
For example, a
stated range of "1 to 10" should be considered to include any and all
subranges between (and
inclusive of) the minimum value of 1 and the maximum value of 10; that is, all
subranges
beginning with a minimum value of 1 or more, (e.g. 1 to 6.1), and ending with
a maximum value
of 10 or less, (e.g. 2.3 to 9.4, 3 to 8, 4 to 7), and finally to each number
1. 2, 3, 4, 5, 6, 7, 8, 9, and
contained within the range.
In the present disclosure, the words "a" or "an" are to be taken to include
both the
10 singular and the plural. Conversely, any reference to plural items
shall, where appropriate,
include the singular.
From the foregoing it will be observed that numerous modifications and
variations can be
effectuated without departing from the true spirit and scope of the novel
concepts of the present
invention. It is to be understood that no limitation with respect to the
illustrated specific
embodiments or examples is intended or should be inferred. The disclosure is
intended to cover
by the appended claims all such modifications as fall within the scope of the
claims.
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