Method of producing diamines and polyamines of the diphenylmethane series
First Claim
1. A process for preparing di- and polyamines of the diphenylmethane series from aniline (1) and formaldehyde (2) in a production plant (10 000), where the molar ratio of total aniline used (1) to total formaldehyde used (2), n(1)/n(2), is always not less than 1.6, comprising:
- (A-I) reacting aniline (1) and formaldehyde (2) in the absence of an acidic catalyst to obtain a reaction mixture (4) comprising an aminal (3), and then at least partly separating an aqueous phase (6) from the reaction mixture (4) to obtain an organic phase (5) comprising the aminal (3);
(A-II) contacting the organic phase (5) which comprises the aminal obtained in step (A-I) with an acidic catalyst (7) in a reactor cascade (3000) composed of i reactors connected in series (3000-1, 3000-2, . . . , 3000-i), where i is a natural number from 2 to 10, wherein;
the first reactor (3000-1) in flow direction is operated at a temperature T3000-1 in the range from 25.0°
C. to 65.0°
C. and is charged with stream (5) and acidic catalyst (7) and optionally with further aniline (1) and/or further formaldehyde (2),every reactor downstream in flow direction (3000-2, . . . , 3000-i) is operated at a temperature of more than 2.0°
C. above T3000-1 and is charged with the reaction mixture obtained in the reactor immediately upstream;
(B) isolating the di- and polyamines of the diphenylmethane series from the reaction mixture (8-i) obtained from step (A-II) in the last reactor (3000-i) by a process comprising;
(B-I) adding a stoichiometric excess of base (9), based on the total amount of acidic catalyst used (7), to the reaction mixture (8-i) obtained in the last reactor (3000-i) in step (A-II) to obtain a reaction mixture (10); and
(B-II) separating the reaction mixture (10) obtained in step (B-I) into an organic phase (11) comprising di- and polyamines of the diphenylmethane series and an aqueous phase (12);
whereinin the event of a change in the production capacity from a starting state A witha mass flow rate m1 of total aniline used in the starting state of m1(A)≠
0,a mass flow rate m2 of total formaldehyde used in the starting state of m2(A)=X(A)·
m2(N), where X(A) is a dimensionless number >
0 and ≤
1 and m2(N) denotes the nameplate load of the production plant (10 000),a molar ratio n(1)/n(2) of total aniline used (1) to total formaldehyde used (2) in the starting state of n(1)/n(2)(A),a molar ratio n(7)/n(1) of total acidic catalyst used to total aniline used in the starting state of n(7)/n(1)(A),a proportion by mass ω
MMDA, based on the total mass of di- and polyamines of the diphenylmethane series, of diamines of the diphenylmethane series of ω
MMDA(A), anda proportion by mass ω
2,4′
-MDA, based on the total mass of diamines of the diphenylmethane series, of 2,4′
-methylenediphenyldiamine in the starting state of ω
2,4′
-MDA(A)to an end state E witha mass flow rate m1 of total aniline used of in the end state m1(E)≠
0,a mass flow rate m2 of total formaldehyde used in the end state of m2(E)=X(E)·
m2(N), where X(E) is a dimensionless number >
0 and ≤
1,a molar ratio n(1)/n(2) of total aniline used (1) to total formaldehyde used (2) in the end state of n(1)/n(2)(E),a molar ratio n(7)/n(1) of total acidic catalyst used to total aniline used in the end state of n(7)/n(1)(E),a proportion by mass ω
MMDA, based on the total mass of di- and of the diphenylmethane series, of diamines of the diphenylmethane series the end state of ω
MMDA(E), anda target proportion by mass ω
2,4′
-MDA for the end state, based on the total mass of diamines of the diphenylmethane series, of 2,4′
-methylenediphenylenediamine, of ω
2,4′
-MDA(E);
by a quantity Δ
X=|X(E)−
X(A)|, with Δ
X≥
0.10, wherein the process comprises at least one change in production capacity that commences at a time t1 and concludes at a time t2, wherein ω
2,4′
-MDA is also altered in such a way that, for the target value of ω
2,4′
-MDA(E) for the end state, either ≥
1.15·
ω
2,4′
-MDA(A) or ≤
0.85·
ω
2,4′
-MDA(A), and wherein;
0.95·
ω
MMDA(A)≤
ω
MMDA(E)≤
1.05·
ω
MMDA(A);
characterized in that, in the period from t1 to t2, the transition state T, with a molar ratio of total aniline used (1) to total formaldehyde used (2) of n(1)/n(2)(T) and a molar ratio of total acidic catalyst used to total aniline used of n(7)/n(1)(T),(i) the temperature in the first reactor (3000-1) in flow direction from step (A-II) is adjusted to a value that differs from the temperature in that reactor during the starting state A by not more than 10.0°
C.;
(ii-1) in the case that m2(E)>
m2(A), the temperature in at least one of the reactors downstream in flow direction (3000-2, . . . , 3000-i), by comparison with the starting state A, is increased by more than 2.0°
C. in such a way that the target end temperature is reached at the latest at time t2, and in all reactors (3000-2, . . . , 3000-i) in which the temperature is not increased it is kept the same within a range of variation of ±
2.0°
C.;
(ii-2) in the case that m2(E)<
m2(A), the temperature in at least one of the reactors downstream in flow direction (3000-2, . . . , 3000-i), by comparison with the starting state A, is lowered by more than 2.0°
C. in such a way that the target end temperature is reached at the latest at time t2, and in all reactors (3000-2, . . . , 3000-i) in which the temperature is not lowered it is kept the same within a range of variation of ±
2.0°
C.;
(iii-1) in the case that ω
2,4′
-MDA(E)≥
1.15·
ω
2,4′
-MDA(A), n(1)/n(2)(T) and n(7)/n(1)(T) are adjusted in such a way that, at time t2;
1.01·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
1.50·
n(1)/n(2)(A), and
0.50·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
0.95·
n(7)/n(1)(A);
wherein, over the entire transition state before reaching time t2, it is always the case that;
0.80·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A), and
0.40·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
1.15·
n(7)/n(1)(A);
(iii-2) in the case that ω
2,4′
-MDA(E)≤
0.85·
ω
2,4′
-MDA(A), n(1)/n(2)(T) and n(7)/n(1)(T) are adjusted in such a way that, at time t2;
0.75·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
0.99·
n(1)/n(2)(A), and
1.05·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
3.50·
n(7)/n(1)(A),wherein, over the entire transition state before reaching time t2, it is always the case that;
0.40·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.00·
n(1)/n(2)(A), and
0.80·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
4.50·
n(7)/n(1)(A).
1 Assignment
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Accused Products
Abstract
The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, by condensing aniline and formaldehyde followed by an acid-catalysed rearrangement at different production capacities with alteration of the isomer composition in the resulting diamines of the diphenylmethane series (altering the 2,4′-MDA content). Adapting the molar ratios of the total used aniline to the total used formaldehyde and of the total used acid catalyst to the total used aniline, and adapting the reaction temperature, allows the rearrangement reaction to be fully completed despite the change in dwell time inevitably associated with a change in production capacity, and allows the formation of undesired by-products to be avoided as far as possible; the intended modification to binuclear content is likewise achieved.
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Citations
11 Claims
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1. A process for preparing di- and polyamines of the diphenylmethane series from aniline (1) and formaldehyde (2) in a production plant (10 000), where the molar ratio of total aniline used (1) to total formaldehyde used (2), n(1)/n(2), is always not less than 1.6, comprising:
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(A-I) reacting aniline (1) and formaldehyde (2) in the absence of an acidic catalyst to obtain a reaction mixture (4) comprising an aminal (3), and then at least partly separating an aqueous phase (6) from the reaction mixture (4) to obtain an organic phase (5) comprising the aminal (3); (A-II) contacting the organic phase (5) which comprises the aminal obtained in step (A-I) with an acidic catalyst (7) in a reactor cascade (3000) composed of i reactors connected in series (3000-1, 3000-2, . . . , 3000-i), where i is a natural number from 2 to 10, wherein; the first reactor (3000-1) in flow direction is operated at a temperature T3000-1 in the range from 25.0°
C. to 65.0°
C. and is charged with stream (5) and acidic catalyst (7) and optionally with further aniline (1) and/or further formaldehyde (2),every reactor downstream in flow direction (3000-2, . . . , 3000-i) is operated at a temperature of more than 2.0°
C. above T3000-1 and is charged with the reaction mixture obtained in the reactor immediately upstream;(B) isolating the di- and polyamines of the diphenylmethane series from the reaction mixture (8-i) obtained from step (A-II) in the last reactor (3000-i) by a process comprising; (B-I) adding a stoichiometric excess of base (9), based on the total amount of acidic catalyst used (7), to the reaction mixture (8-i) obtained in the last reactor (3000-i) in step (A-II) to obtain a reaction mixture (10); and (B-II) separating the reaction mixture (10) obtained in step (B-I) into an organic phase (11) comprising di- and polyamines of the diphenylmethane series and an aqueous phase (12); wherein in the event of a change in the production capacity from a starting state A with a mass flow rate m1 of total aniline used in the starting state of m1(A)≠
0,a mass flow rate m2 of total formaldehyde used in the starting state of m2(A)=X(A)·
m2(N), where X(A) is a dimensionless number >
0 and ≤
1 and m2(N) denotes the nameplate load of the production plant (10 000),a molar ratio n(1)/n(2) of total aniline used (1) to total formaldehyde used (2) in the starting state of n(1)/n(2)(A), a molar ratio n(7)/n(1) of total acidic catalyst used to total aniline used in the starting state of n(7)/n(1)(A), a proportion by mass ω
MMDA, based on the total mass of di- and polyamines of the diphenylmethane series, of diamines of the diphenylmethane series of ω
MMDA(A), anda proportion by mass ω
2,4′
-MDA, based on the total mass of diamines of the diphenylmethane series, of 2,4′
-methylenediphenyldiamine in the starting state of ω
2,4′
-MDA(A)to an end state E with a mass flow rate m1 of total aniline used of in the end state m1(E)≠
0,a mass flow rate m2 of total formaldehyde used in the end state of m2(E)=X(E)·
m2(N), where X(E) is a dimensionless number >
0 and ≤
1,a molar ratio n(1)/n(2) of total aniline used (1) to total formaldehyde used (2) in the end state of n(1)/n(2)(E), a molar ratio n(7)/n(1) of total acidic catalyst used to total aniline used in the end state of n(7)/n(1)(E), a proportion by mass ω
MMDA, based on the total mass of di- and of the diphenylmethane series, of diamines of the diphenylmethane series the end state of ω
MMDA(E), anda target proportion by mass ω
2,4′
-MDA for the end state, based on the total mass of diamines of the diphenylmethane series, of 2,4′
-methylenediphenylenediamine, of ω
2,4′
-MDA(E);by a quantity Δ
X=|X(E)−
X(A)|, with Δ
X≥
0.10, wherein the process comprises at least one change in production capacity that commences at a time t1 and concludes at a time t2, wherein ω
2,4′
-MDA is also altered in such a way that, for the target value of ω
2,4′
-MDA(E) for the end state, either ≥
1.15·
ω
2,4′
-MDA(A) or ≤
0.85·
ω
2,4′
-MDA(A), and wherein;
0.95·
ω
MMDA(A)≤
ω
MMDA(E)≤
1.05·
ω
MMDA(A);characterized in that, in the period from t1 to t2, the transition state T, with a molar ratio of total aniline used (1) to total formaldehyde used (2) of n(1)/n(2)(T) and a molar ratio of total acidic catalyst used to total aniline used of n(7)/n(1)(T), (i) the temperature in the first reactor (3000-1) in flow direction from step (A-II) is adjusted to a value that differs from the temperature in that reactor during the starting state A by not more than 10.0°
C.;(ii-1) in the case that m2(E)>
m2(A), the temperature in at least one of the reactors downstream in flow direction (3000-2, . . . , 3000-i), by comparison with the starting state A, is increased by more than 2.0°
C. in such a way that the target end temperature is reached at the latest at time t2, and in all reactors (3000-2, . . . , 3000-i) in which the temperature is not increased it is kept the same within a range of variation of ±
2.0°
C.;(ii-2) in the case that m2(E)<
m2(A), the temperature in at least one of the reactors downstream in flow direction (3000-2, . . . , 3000-i), by comparison with the starting state A, is lowered by more than 2.0°
C. in such a way that the target end temperature is reached at the latest at time t2, and in all reactors (3000-2, . . . , 3000-i) in which the temperature is not lowered it is kept the same within a range of variation of ±
2.0°
C.;(iii-1) in the case that ω
2,4′
-MDA(E)≥
1.15·
ω
2,4′
-MDA(A), n(1)/n(2)(T) and n(7)/n(1)(T) are adjusted in such a way that, at time t2;
1.01·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
1.50·
n(1)/n(2)(A), and
0.50·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
0.95·
n(7)/n(1)(A);wherein, over the entire transition state before reaching time t2, it is always the case that;
0.80·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A), and
0.40·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
1.15·
n(7)/n(1)(A);(iii-2) in the case that ω
2,4′
-MDA(E)≤
0.85·
ω
2,4′
-MDA(A), n(1)/n(2)(T) and n(7)/n(1)(T) are adjusted in such a way that, at time t2;
0.75·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
0.99·
n(1)/n(2)(A), and
1.05·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
3.50·
n(7)/n(1)(A),wherein, over the entire transition state before reaching time t2, it is always the case that;
0.40·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.00·
n(1)/n(2)(A), and
0.80·
n(7)/n(1)(A)≤
n(7)/n(1)(T)≤
4.50·
n(7)/n(1)(A).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
the temperature in each of the reactors downstream in flow direction (3000-2, . . . , 3000-i) is set to a value in the range from 35.0°
C. to 200.0°
C.
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4. The process of claim 3, in which it is always the case that
T3000-1 is set to a value in the range from 30.0° - C. to 60.0°
C. andthe temperature in each of the reactors downstream in flow direction (3000-2, . . . , 3000-i) is set to a value in the range from 50.0°
C. to 180.0°
C.
- C. to 60.0°
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5. The process of claim 1, in which the acidic catalyst (7) is a mineral acid.
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6. The process of claim 1, in which step (B) further comprises:
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(B-III) washing the organic phase (11) with washing liquid (13); (B-IV) separating the mixture (14) obtained in step (B-III) into an organic phase (16) comprising di- and polyamines of the diphenylmethane series and an aqueous phase (15); and (B-V) distilling the organic phase (16) from step (B-IV) to obtain the di- and polyamines of the diphenylmethane series (18), with removal of a stream (17) comprising water and aniline.
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7. The process of claim 6, further comprising:
(C) recycling stream (17), optionally after workup, into step (A-I) and/or, if the optional addition of further aniline (1) in step (A-II) is conducted, into step (A-II).
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8. The process of claim 1, in which the molar ratio of total aniline used (1) to total formaldehyde used (2), n(1)/n(2), in all states of operation (A, T, E) is adjusted to a value of 1.6 to 20.
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9. The process of claim 1, in which the values of n(1)/n(2), n(7)/n(1) and of the temperature of each reactor j of the reactor cascade (3000), T3000-j, that exist in each case at time t2 are retained for the duration of the production with the formaldehyde mass flow rate m2(E).
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10. The process of claim 1, in which the target end value for the molar ratio of total aniline used to total formaldehyde used, n(1)/n(2)(E), and the target end value for the molar ratio of total acidic catalyst used to total aniline used, n(7)/n(1)(E), are established by continuously adjusting the value of m2 and at least one of the values of m1 and/or m7 until time t2.
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11. The process of claim 1, in which the period from t1 to t2 lasts from 1.00 minute to 120 minutes.
Specification