METHOD OF PRODUCING DIAMINES AND POLYAMINES OF THE DIPHENYLMETHANE SERIES
First Claim
Patent Images
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, whereinthe 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), andevery 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 ml 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) anda 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)to an end state E witha mass flow rate ml 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) anda target proportion by mass ω
MMDA, based on the total mass of di- and polyamines of the diphenylmethane series, of diamines of the diphenylmethane series for the end state of ω
MMDA(E)by a quantity Δ
X=IX(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
MMDA is also altered in such a way that, for the target value of ω
MMDA(E) for the end state, either≥
1.05·
ω
MMDA(A) or ≤
0.95·
ω
MMDA(A), and wherein;
0.90·
n(7)/n(1)(A)≤
n(7)/n(1)(E)≤
1.10·
n(7)/n(1)(A);
characterized in that, in the period from ti 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 no later than 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 no later than 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
MMDA(E)≥
1.05·
ω
MMDA(A), n(1)/n(2)(T) is adjusted such that, at time t2;
1.05·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.00·
n(1)/n(2)(A);
where it is always the case throughout the transition state prior to attainment of time t2 that;
0.80·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A);
(iii-2) in the case that ω
MMDA(E)≤
0.95·
ω
MMDA(A), n(1)/n(2)(T) is adjusted such that, at time t2;
0.50·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
0.95·
n(1)/n(2)(A)where it is always the case throughout the transition state prior to attainment of time t2 that;
0.40·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A).
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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 content of diamines of the diphenylmethane series (altering the binuclear content). Adapting the molar ratio of the total used aniline to the total used formaldehyde 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.
0 Citations
15 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:
-
(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), andevery 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 ml 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) and 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)to an end state E with a mass flow rate ml 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) and a target proportion by mass ω
MMDA, based on the total mass of di- and polyamines of the diphenylmethane series, of diamines of the diphenylmethane series for the end state of ω
MMDA(E)by a quantity Δ
X=IX(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
MMDA is also altered in such a way that, for the target value of ω
MMDA(E) for the end state, either≥
1.05·
ω
MMDA(A) or ≤
0.95·
ω
MMDA(A), and wherein;
0.90·
n(7)/n(1)(A)≤
n(7)/n(1)(E)≤
1.10·
n(7)/n(1)(A);characterized in that, in the period from ti 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 no later than 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 no later than 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
MMDA(E)≥
1.05·
ω
MMDA(A), n(1)/n(2)(T) is adjusted such that, at time t2;
1.05·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.00·
n(1)/n(2)(A);where it is always the case throughout the transition state prior to attainment of time t2 that;
0.80·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A);(iii-2) in the case that ω
MMDA(E)≤
0.95·
ω
MMDA(A), n(1)/n(2)(T) is adjusted such that, at time t2;
0.50·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
0.95·
n(1)/n(2)(A)where it is always the case throughout the transition state prior to attainment of time t2 that;
0.40·
n(1)/n(2)(A)≤
n(1)/n(2)(T)≤
2.50·
n(1)/n(2)(A). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Current AssigneeCovestro Deutschland AG
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Original AssigneeCovestro Deutschland AG
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InventorsKNAUF, Thomas, WERSHOFEN, Stefan, GRUNER, Klaus-Gerd, HARTJES, Volker
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current
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CPC Class CodesC07C 209/54 by rearrangement reactionsC07C 209/60 by condensation or addition...C07C 209/78 from carbonyl compounds, e....C07C 211/48 N-alkylated aminesC07C 211/50 with at least two amino gro...
