TWI600636B - Process for preparing a diamine/dicarboxylic acid salt - Google Patents

Description

Method for preparing diamine/dicarboxylate

The present invention relates to a process for preparing a diamine/dicarboxylate comprising contacting a diamine with a dicarboxylic acid to provide a reaction mixture, wherein the diamine and the dicarboxylic acid are reacted to form a diamine/dicarboxylate .

Diamine/dicarboxylates are widely used as starting materials for the manufacture of polyamines. Particularly advantageously, the diamine/dicarboxylate salt is in the form of solid particles.

Poly(hexamethylene hexamethyleneamine) (Nylon 6,6) polymers are typically commercially produced by first producing an aqueous salt solution from their monomeric hexamethylenediamine and adipic acid. The diamine is supplied as a dilute aqueous solution such that the resulting solution of hexamethylene diammonium adipate (6,6 salt, commonly referred to as nylon 6,6 salt) typically contains about 50% by weight water. This solution is then used as the starting material for the solution/melt polymerization of the nylon 6,6 and the starting reaction medium. Occasionally, an aqueous solution of nylon 6,6 salt is also sold, which is typically delivered as a warm solution of about 50% by weight. Storage time is limited by unnecessary polymerization and this solution requires warm storage to avoid solids from precipitating in the storage container. Nylon 6,6 salt can also be purchased as a solid. Techniques for precipitating salts from solutions are known, for example, by adding a non-solvent of a salt to a solution, for example, isopropanol. These methods require their recovery from the solution to non-solvent. Salt can be recycled from a stable, free-flowing powder that can be easily transported for use in the distance. This is less dangerous than the harsh volatile hazardous aqueous solution carrying hexamethylenediamine, which is used to transport the typical form of this diamine to maintain a solid state at moderate temperatures.

Another manufacture of diamine/dicarboxylate in the form of substantially solid particles The method is known from U.S. Patent No. 5,801,278. In the process of US Pat. No. 5,801,278, the reaction of the diamine with the dicarboxylic acid is carried out in the presence of from about 0.5 to about 25 wt% water, preferably from 2 to 10 wt% water, based on the weight of the reaction mixture, while reacting. The mixture is provided such that the reaction mixture is in the form of substantially solid particles. These conditions are met by using temperatures well below room temperature, more particularly in the use of a low temperature medium such as dry ice or liquid nitrogen in the reaction mixture. The reactants are mixed for a short time and thereafter kneaded to allow the reactants to react. If the reaction is carried out in a non-cryogenic medium, it will result in a paste rather than a free-flowing powder. Furthermore, the homogeneity of the formed product is not good.

In U.S. Patent No. 5,874,520, the anhydrous nylon salt is produced in a solid state process wherein the solid diamine carbamate is contacted and mixed with the solid dicarboxylic acid. These compounds are specifically mixed under high shear conditions by revealing the "new" particle surface with unreacted molecules by friction grinding or the like. A low temperature medium (for example, dry ice or nitrogen) is used not only to control the heat of reaction but also to maintain the reaction in a solid state.

In U.S. Patent No. 5,874,520, the substantially anhydrous nylon salt is produced in a solid state process wherein the solid diamine carbamate is contacted with the solid dicarboxylic acid in a near-instantaneous reaction under high shear conditions. Mix to produce this salt. As mentioned in US 5,874,520, the reaction can be continued by removing the salt formed at the particle-particle interface (such as by rubbing or the like) to reveal the "new" particle surface with unreacted molecules.

The use of organic solvents or cryogenic media in the above manner complicates the process and is generally undesirable or even prohibits large-scale production. Use low temperature media One particular disadvantage is that the water is extracted from the ambient air, which decomposes some of the carbamate (as mentioned in US 5,874,520) and also prevents the salt from being recovered from the process as a stable free-flowing powder. The use of chemicals such as dry ice (CO2) and/or nitrogen, which are later released to the surroundings, involves additional costs and is environmentally unfavourable due to the carbon footprint of the nitrogen and CO2 used.

It is an object of the present invention to provide a process for the preparation of diamine/dicarboxylates which eliminates the necessity of using organic solvents or cryogenic media. A further object is to provide a process in which the diamine/dicarboxylate salt is in the form of solid particles, preferably a free-flowing powder.

This object has been achieved by a process according to the invention comprising the step of contacting a diamine with a dicarboxylic acid to provide a reaction mixture, wherein the diamine and the dicarboxylic acid are reacted to form a diamine/dicarboxylate, wherein (a) the dicarboxylic acid comprises an aromatic dicarboxylic acid; (b) the dicarboxylic acid is provided in powder form; (c) the diamine is provided in liquid form; (d) the contact is made by The amine liquid is gradually applied to the dicarboxylic acid powder while maintaining the fixed movement of the dicarboxylic acid powder; (e) directly maintaining the reaction mixture for a certain period of time after the completion of the application, (f) (d) and (e) ) is carried out at a temperature above 0 ° C and below the owner's temperature: the boiling temperature of the diamine and the melting temperature of the dicarboxylic acid, the diamine/dicarboxylate and any intermediate reaction product, and (g) d) and (e), the reaction mixture is relative to the total weight of the diamine and the dicarboxylic acid The composition contains up to 5% by weight of water.

The efficacy of the method according to the invention is that the salt is obtained in the form of substantially anhydrous solid particles. By "substantially anhydrous" it is meant herein that the salt typically contains no more than 5% by weight water relative to the total weight. The salt recovered from this process stabilizes a substantially free flowing powder. Salts are obtained as generally homogeneous products and are suitable for use in the general commercial process for making polyamine polymers. This result is achieved without a precipitation step involving an organic solvent and without using a low temperature medium in the reaction mixture. This method does not require high shear mixing and this method can be easily extended to industry specifications.

The temperatures at which (d) and (e) are carried out are also referred to herein as processing temperatures. This temperature is measured in the reaction mixture.

The melting temperature (Tm) is hereby understood to be the temperature measured by a DSC method according to ISO-11357-3.2, 2009, in a nitrogen atmosphere, and at a heating and cooling rate of 20 ° C/min. Here, Tm is the temperature at the peak of the melting peak of the first heating cycle.

The boiling temperature of the diamine is generally understood herein to be the boiling temperature of the prevailing pressure measurement when the diamine is administered. In a preferred embodiment, (d) and (e) are carried out at a temperature below the boiling temperature of the diamine measured during the lowest pressure applied during the diamine administration.

The term "gradually applied" is understood here to mean that the diamine is applied in a sufficiently low amount per unit time so that the particles are not excessively wetted at any time, and the particles are prevented from sticking together, blocking, and agglomerating. . This excludes the diamine from being used at once or nearly as such. However, this does not exclude diamines. When the time is short, it seems that the reaction of the added diamine with the dicarboxylic acid is reasonably fast, and therefore, the diamine is prevented from accumulating in an unreacted form. The reaction rate may depend on the form of the diamine and the dicarboxylic acid. A large-scale operation suitable for use in, for example, a special combination of a diamine and a dicarboxylic acid can be simply changed by a routine measurement by a routine measurement, for example, starting at a low application rate and gradually increasing speed.

The reaction mixture maintains a fixed movement during the minimum duration of the period after the completion of the application, typically at least sufficient to avoid sticking and agglomeration upon discharge from the reactor in which the process is carried out. This is affected by various factors such as the rate of application, the reaction temperature, and the combination of specific diamines and dicarboxylic acids. Suitably, the time is in the range starting from 10 minutes and comprising from 10 minutes up to 1 hour and including 1 hour. This time can also be longer than 1 hour. Depending on the processing conditions, especially at very slow application rates, especially at the very slow application rate at the end of the diamine administration, this time can be shorter, for example between 0 and 10 minutes.

The diamine and dicarboxylic acid in the reaction mixture can be present in a wide range of molar ratios, and initially, the carboxylic acid is present in a greater excess than the diamine. During the diamine administration, this excess is reduced and the molar amount is close to the equivalent amount, while if another diamine is added, the diamine is in excess of the diacid. This is not a problem as the addition of a slight excess of diamine will still result in a stable solid particulate material.

However, a large deviation of the molar ratio from the equivalent amount may be less desirable for further processing of the polyamide polymer, because the diamine needs to be supplemented with diamine, and in the case of an excess of diamine, this requires an additional two. The carboxylic acid, and/or due to the greater excess of diamine, results in excessive loss of volatile amines. Suitable for The molar ratio of diamine to dicarboxylic acid (D/DA) is in the range of 0.9-1.1. Preferably, the D/DA molar ratio is in the range of 0.95 to 1.05. In practice, preferred diamines are at least equal in amount and, therefore, have a D/DA of at least 1.0, or a slight excess, such as having a D/DA molar ratio of from about 1.005 to 1.02, corresponding to 0.5 to 2%. Moly excess diamine. Therefore, more preferably, the D/DA ratio is in the range of 1.00 to 1.02. Even with this low excess, or even no excess, ie with a molar amine, the reaction is completely converted or substantially so, ie if any are observed (for example, with wide-angle X-ray diffraction (XRD) )), a small amount of residual dicarboxylic acid. Of course, the presence of a specific amount of residual dicarboxylic acid cannot be excluded with less than the molar amount of the diamine.

The diamines and dicarboxylic acids used in the process according to the invention are suitably composed of a mixture of different compounds, ie a mixture of different diamines and/or a mixture of different dicarboxylic acids. This mixture is selected to provide a preferred composition of the polyamide polymer, depending on the desired polymer properties.

In a particular embodiment, the dicarboxylic acid is a mixture of adipic acid and an aromatic dicarboxylic acid. This salt has not only the form of solid particles but also the defects of the dicarboxylic acid mixture, as is the case with several semi-aromatic polyamines manufactured on a commercial scale.

It is to be noted that the phrase "a" or "an", as used herein, is meant to include the singular and plural, unless Others are clearly stated.

In general, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are present in a molar ratio of between 90:10 and 10:90, even depending on the particular diamine and dicarboxylic acid component, 90:10 or higher. The ratio can be used to still obtain a solid particulate material. More Preferably, the molar ratio ranges from 80:20 up to and including 20:80.

In a preferred embodiment, the mixture of the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid is a dry blend of the aliphatic dicarboxylic acid solid particles and the aromatic dicarboxylic acid solid particles. It is observed that although the dicarboxylic acid is not mixed in a molecular ratio before the salt production method, the salt is obtained in the form of solid particles, even when the corresponding salt of the aliphatic dicarboxylic acid, that is, no aromatic dicarboxylic acid, is in the form of solid particles. It creates difficulties or prohibits this from forming. The dry blend is used to avoid the necessity of any complicated pre-mixing steps, such as dissolution, mixing, and precipitation steps.

In the case of compositions using different dicarboxylic acids, different salts may be formed, which may be reflected by different melting peaks, particularly where different dicarboxylic acids are used in the form of a dry blend. These melting temperatures are all considered when selecting processing conditions. This processing temperature needs to be kept below the melting temperature of each.

In a particular embodiment, the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid are present in a molar ratio of between 10:90 and 50:50.

In another particular embodiment, the dicarboxylic acid consists essentially of an aromatic dicarboxylic acid, which means that the dicarboxylic acid is more particularly from 90 to 100 mole % of aromatic dicarboxylic acid and 10-0 mole The ear is composed of an aliphatic dicarboxylic acid. Preferably, the dicarboxylic acid is composed of 95-100 mol% aromatic dicarboxylic acid, and optionally 5-0 mol% of the aliphatic dicarboxylic acid. The percentage of moles (% by mole) mentioned is relative to the total moles of aliphatic dicarboxylic acid and aromatic dicarboxylic acid.

Aromatic dicarboxylic acids not only facilitate the formation of diamine/dicarboxylates from solid particulate materials, but also readily react with diamines. a salt mainly composed of a dicarboxylic acid composed of an aromatic dicarboxylic acid, and further preferably an aliphatic dicarboxylic acid The main salt combination is used to make polyamine. Here, the salt mainly composed of an aliphatic dicarboxylic acid contains or is, for example, a nylon 6,6 salt, that is, a salt of 1,6-hexanediamine and adipic acid. The nylon 6,6 salt is manufactured on a very large scale and is available worldwide. The combination of such salts enables the manufacture of polyamines having a wide variety of compositions without the need to have a large stock of different salts or to mix additional amines or acids.

Examples of suitable aromatic dicarboxylic acids include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid, which may be individual and any of them. Used in combination. Preferably, the aromatic dicarboxylic acid comprises 2,6-naphthalene dicarboxylic acid and/or terephthalic acid. More preferably, the aromatic dicarboxylic acid comprises at least 25 mol%, more preferably at least 50 mol%, more preferably at least 75 mol% of terephthalic acid, or even terephthalic acid Composition. Here, the molar % is the total molar amount relative to the aromatic dicarboxylic acid.

The aliphatic dicarboxylic acid in the process according to the invention may be a non-cyclic, linear or branched dicarboxylic acid or cyclic dicarboxylic acid. Suitably, the aliphatic dicarboxylic acid is an aliphatic dicarboxylic acid having 4 to 18 carbon atoms, for example, 6, 8, 10 or 12 carbon atoms. Suitably, the acyclic dicarboxylic acid is selected from the group consisting of 1,6-hexanedioic acid (also known as adipic acid), 1,8-octanedioic acid, 1,9-sebacic acid, 1,10-anthracene Acid (also known as lactone), 1,11-undecanedioic acid, 1,12-dodecanedioic acid, 1,13-tridecanedioic acid, 1,14-tetradecanedioic acid, 1,15-pentadecanedioic acid, 1,16-hexadecanedioic acid, 1,17-heptadecanedioic acid, and a group of 1,18-octadecanedioic acid. A suitable cyclic aliphatic dicarboxylic acid is trans-1,4-cyclohexanedicarboxylic acid.

Preferably, the aliphatic dicarboxylic acid comprises adipic acid or sebacic acid. Adipic acid is most widely used in polyamines. Azelaic acid can be obtained from renewable resources.

In addition, monoacids such as benzoic acid can be produced from the final polymer obtained. Any desired amount of material is added to the acid mixture. Typically, about 0.5 to 3 mole percent (relative to the acid already present) of the monoacid is used in the polymerization process to control the molecular weight of the polyamine. Suitably, if used in a salt preparation process, the amount of monocarboxylic acid is from 0.01 to 5, preferably from 0.1 to 3 mol%, relative to the total moles of dicarboxylic acid.

The diamine in the process according to the invention may be selected from diamines suitable as starting materials for the manufacture of polyamines. Such diamines include aliphatic diamines, lipid cyclic diamines, aromatic diamines, and the like. Suitable aromatic diamines are, for example, isophthalamide and p-phenylenediamine. Suitably, the aliphatic diamine is an aliphatic diamine having 2 to 18 carbon atoms which may be linear or branched, or alicyclic. More preferably, the aliphatic diamine has from 2 to 12 carbon atoms per molecule, such as 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5- Pentamethylenediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12- Dodecanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine. Examples of suitable aliphatic cyclic diamines are 1,4-trans-cyclohexanediamine and 1,4-trans-diaminomethylcyclohexane.

Preferred diamines are most widely used in semi-aromatic polyamines produced on a large scale, including 1,4-butanediamine, 1,6-hexanediamine, and 1,9-nonanediamine.

Compared to shorter chain diamines having from 2 to 7 carbon atoms per molecule, in the case of longer chain diamines, such as C8-C18 diamines, the reaction is slow and requires longer application times and/or High reaction temperature. Preferably, the C8-C18 diamine is combined with a C2-C7 diamine. The amount of C2-C7 diamine can be maintained relatively low, which has a significant effect on the reaction rate and, therefore, allows for shorter application times and/or higher reaction temperatures. Suitably, between a short chain diamine and a long chain diamine The molar ratio is in the range of 1/99-25/75, more particularly 2/98-20/80, or even 5/95-15/85. Of course, mixtures of short chain diamines having a higher molar amount are also suitable for the salt preparation process.

Preferably, the short chain diamine is a C2-C6 diamine. More preferably, the diamine used in the process according to the invention comprises 1,4-butanediamine and/or 1,6-hexanediamine, more preferably 1,4-butanediamine.

As mentioned above, this method is carried out at a temperature lower than the boiling temperature of the prevailing pressure measurement when the diamine is administered. If the diamine used in the process of the invention is a mixture of at least two different diamines, the boiling temperature of the diamine (Tb diamine) (the temperature of the process is kept below this temperature) is at least two diamines and The lowest boiling temperature of any of its azeotropes in the event of occurrence. The boiling temperature, individually referred to herein as the boiling temperature, is based on the boiling temperature of the prevailing pressure measurement of the contact and reaction. The purpose is to avoid evaporation of the diamine which is not in contact with the diamine and the dicarboxylic acid.

In a preferred embodiment, steps (d) and (e) are carried out at a temperature below the diamine boiling temperature measured at the lowest pressure applied during the diamine administration. In the case of a mixture of at least two different diamines, the boiling point of the diamine is the lowest of the boiling temperatures of any of the at least two diamines and any azeotropes thereof.

In the method according to the present invention, the diamine and the dicarboxylic acid are contacted by gradually applying the diamine liquid to the dicarboxylic acid powder while maintaining the fixed movement of the dicarboxylic acid powder. Preferably, the diamine is applied to the dicarboxylic acid powder such that it does not first contact a portion of the side wall of one of the reactor vessels in which the process is carried out. This is used to avoid adhesion to the sidewalls and the formation of the dicarboxylic acid powder and thereafter. The salt forms a mass. Suitably, the contacting is carried out by spraying or dripping the diamine onto the mobile dicarboxylic acid powder.

The method according to the invention can in principle be carried out in any form of reactor in which the powder material can be held stationary by mechanical agitation. A mechanically stirred powder bed is formed by mechanical agitation. Suitable reactor systems for carrying out the process, for example, drum mixers, coulter mixers, planetary screw mixers (also known as Nauta mixers), conical mixers, and fluids A chemical bed (for example, a circulating fluidized bed reactor). The mixer may also comprise a wall heating and/or cooling, as is typically the case with a dryer. In this case, the mixer may also be referred to as a dryer such as a drum dryer, a conical dryer, and a planetary screw dryer.

These mixers are all low shear mixers. Further information on these and other low shear mixer devices can be found in the book "Handbook of Industrial Mixing-Science and Practice", edited by Paul, Edward L.; Atiemo-Obeng, Victor A.; Kresta, Suzanne M. (publisher: John Wiley &Sons;2004;; ISBN: 978-0-471-26919-9; Electronic ISBN: 978-1-60119-414-5), more particularly in Chapter 15, Section 15.4 And part 15.11.

The fact that the method according to the invention can be carried out without applying high shear and still providing a high degree of conversion is highly surprising. In fact, the fixed movement of steps (d) and (e) of the process according to the invention can be accomplished with low shear agitation to avoid wear of the dicarboxylic acid powder. With this low shear, there is no significant separation of the salt particles, and more particularly, the diamine/dicarboxylate d10 formed is the same as the starting dicarboxylic acid powder. In fact, the wear can be very low, or even a little bit No, the particle size distribution geometry is unaffected except that the dicarboxylic acid powder particle size may increase more during the reaction with the diamine.

The advantage of this low shear agitation without the wear of the dicarboxylic acid powder is that the amount of fines produced during this process is low, and the problems of fouling, dust, sagging and reduced fluidity due to blockage of fines are reduced during storage. .

In a preferred embodiment of the process according to the invention, the dicarboxylic acid powder used therein comprises a low content of particles having a small particle size. Also preferred is a dicarboxylic acid powder having a narrow particle size distribution. The advantage of the diamine/dicarboxylate salt formed as such is that it has fewer small particles, a relatively narrow particle size distribution, and a better flow property of selectivity. Suitably, a dicarboxylic acid powder system having a low content of small particles and/or a narrow particle size distribution is used in combination with low shear agitation.

Suitably, the dicarboxylic acid powder has a particle size distribution with a d10 of at least 15 μm and a d90 of at most 1000 μm. Suitably, the dicarboxylic acid powder also has an intermediate particle size (d50) in the range of from 40 to 500 μm. Here, the particle size distribution is measured by laser granulation at 20 ° C according to the method of ISO 13320.

Preferably, the d10 of the particle size distribution of the dicarboxylic acid powder is in the range of from 15 to 200 μm, more preferably in the range of from 16 to 160 μm. Preferably, the d90 is in the range of from 100 to 1000 μm, more preferably in the range of from 150 to 800 μm. Preferably, the d50 is in the range of 40-400 μm, more preferably in the range of 40-400 μm. Also preferably, the dicarboxylic acid powder has a particle size distribution of up to a span of 5 (defined by the ratio of (d84-d16) / d50). The advantage is that the formed diamine/dicarboxylate also has a narrow particle size distribution and the flow system is One step improvement.

The reaction of the diamine with the dicarboxylic acid is carried out such that the reaction mixture is continuously in the form of substantially solid particles, i.e., individual particles are present throughout the diamine addition period and thereafter. The reaction of the diamine with the dicarboxylic acid is strongly exothermic, and local overheating can cause some minor agglomeration. Without any temperature control, the reaction mixture will form a paste and agglomerate into a single material depending on the reactants used, rather than maintaining the form of substantially solid particles. However, by applying the method according to the present invention, wherein the diamine is gradually applied, and the reaction mixture remains in a continuously moving state during diamine administration and further reaction, selectively supported by external temperature control means, the temperature is easily Controlled and partially overheated if present, is minimal.

The temperature control used to maintain substantially solid particulate form is suitably achieved during the transfer of the thermal system from the reaction mixture during the gradual addition of the diamine and mechanically agitating the reaction mixture to maintain the temperature of the reaction mixture (ie, processing temperature). At the temperature shown above, that is, the lowest of the melting temperature of the intermediate reaction product at 0 ° C and the boiling temperature of the diamine (Tb diamine), the dicarboxylic acid, the diamine/dicarboxylate, and the reaction mixture. between. This heat transfer is advantageously accomplished by using a reactor equipped with a heat exchanger. The heat exchanger can be, for example, an internal heat exchanger, such as a baffle having a cooling medium within the baffle, and/or an external heat exchanger, such as a double wall reactor vessel having a cooling medium within the double wall. .

The processing temperature is suitably selected to be lower than the boiling temperature of water. Therefore, the processing temperature can also be selected to be equal to or higher than the boiling temperature of water. If the processing temperature is equal to or higher than the boiling temperature of water under the prevailing conditions of this method Degrees, care should be taken to keep the water content in the reaction mixture as low as possible, preferably less than 1% by weight relative to the total weight of the reaction mixture, and/or to avoid the presence of cold spots where water vapor condenses and powder The particles will stick to the wall. The latter can be achieved by using a reactor having a wall temperature above the boiling temperature of the water. The processing temperature can still be kept below the upper limit by applying a sufficiently low diamine application rate. By applying a processing temperature above the boiling temperature of the water, a diamine/dicarboxylate in the form of solid particles having a lower water content is obtained. Special care can be taken to avoid entrainment and removal of the diamine together with the water vapor.

Suitably, the diamine and dicarboxylic acid are contacted at a temperature between 0 ° C and the boiling temperature of the water. Here, the boiling point is the boiling point of the prevailing pressure measurement when the diamine is administered. This method is selectively carried out under atmospheric conditions. This method and feed can be carried out at pressures above and/or below atmospheric pressure. Preferably, a slight excess pressure is applied, optionally in an inert atmosphere such as nitrogen or argon to avoid inhaling air.

A particularly preferred mode of carrying out the invention is to expose the dicarboxylic acid in powder form to a low ambient temperature, i.e., room temperature, and thereafter to add a diamine in liquid (melt) form, optionally containing up to about 2% of the water mixed with it. With such amines, some heating may be required to maintain these amines in liquid form for ease of addition to the reaction mixture. Furthermore, the rate of addition of the liquid diamine can be easily controlled to match the thermal transfer conditions, i.e., the liquid addition can be adjusted to a sufficiently low rate to avoid paste formation.

Different from the conventional diamine/dicarboxylate forming method, which is carried out in an aqueous solution containing about 50% by weight of water, the water content of the reaction mixture in the method of the present invention is in a much lower amount, that is, relative to the reaction. Mixture weight, to More than 5% by weight, preferably up to 1% by weight. The water content can be even less than 0.5% by weight. Even at low water contents, the salt formation reaction occurs to a sufficient extent to facilitate formation of the salt in a sufficiently short time and reasonably with good homogeneity. By maintaining the water content within such limits, the diamine/dicarboxylate salt is recovered as a free flowing or substantially so powder which promotes its subsequent processing.

Diamine/dicarboxylates which can be stored and transported substantially in the form of solid particles are useful starting materials for the manufacture of polyamine polymers. Salts are useful in the manufacture of conventional aqueous solutions containing about 50% by weight water, which are used in the known commercial processes for making polyamine polymers.

The invention is also directed to a diamine/dicarboxylate obtainable by the process according to the invention as described above, or any embodiment thereof. Preferably, the inventors are anhydrous salts which comprise less than 0.5% by weight water relative to the total weight of the salt.

The salt obtained by the process according to the invention is free flowing, or substantially so, i.e. at least flows easily.

The fluidity of the powder material can be measured by different methods. A suitable method is based on the shear test method of ASTM D6773. This test can be implemented with the Schulze Ringshear tester. For this test, the fluidity is defined as the consolidation stress, σ1, the ratio of unconstrained yield strength, σc, (ffc). For materials that flow easily, fFc needs to be higher than 4, and more particularly between 4 and 10. For free-flowing materials, fFc requires at least 10. According to Schulze, materials with 4 or less ffc are too viscous for proper fluidity.

This is a further application method in which the fluidity can be consolidated at 3 kPa at 20 ° C after a storage time of 10 minutes, in accordance with ASTM D6773. The shear test method was measured with a Schulze Ringshear tester. The anhydrous diamine/dicarboxylate according to the present invention has a fluidity (ffc) of more than 4, preferably more than 7, and more preferably more than 10.

It has been found that the diamine/dicarboxylate obtained by the process according to the invention has a particular morphology which can be observed by microscopic techniques, more particularly by scanning electron microscopy (SEM). The diamine/dicarboxylate is a particulate material composed of polycrystalline particles, and the individual particles are composed of a plurality of microcrystalline particles and/or microcrystalline regions. Microcrystalline particles can be seen on the surface of all particles. The microcrystalline particles have a relatively narrow particle size distribution. As observed from the SEM images obtained by dicing the granules, the granules are composed of such granules or microcrystalline regions throughout the granules. The average size of the microcrystalline particles within the particles was observed to be less than on the surface.

Microcrystalline particles typically have small particle sizes that are much smaller than such particles. Even the smallest particles appear to consist of a number of microcrystalline particles.

Suitably, the particles are composed of microcrystalline particles having a diameter-based particle size distribution with a d90 of at most 2.5 μm. By this is meant that at least 90% of the total number of microcrystalline particles has an average diameter of at most 2.5 μm.

Also suitably, the particles are composed of microcrystalline particles having a volume-based particle size distribution with a d90 of at most 5 μm. This means that at least 90% of the total volume of the microcrystalline particles consists of microcrystalline particles having an average diameter of at most 5 μm.

Here, the diameter is the average diameter of individual microcrystalline particles as measured by software support image analysis of the SEM image taken from the particle surface area as further described below. Soft system used by Olympus America Inc "Analysis.auto", version 5.0. Based on this, the diameter-based particle size distribution and the volume-based particle size distribution were analyzed.

For the representative and reliable measurement of the size of the microcrystalline region, the average diameter of the individual microcrystalline particles, and the diameter-based particle size distribution and the diameter-based particle size, the image of the minimum three different particles is required. It is analyzed that for each particle, a representative surface area needs to be selected and, on average, at least 75 individual particles are included via particle analysis. Crystals of different particles can be combined on a single column to calculate a single overall particle size distribution.

In special cases, the polycrystalline particles, or a large part of them, especially larger particles, have a spherical shape. The term "spherical" is understood here to have a rounded edge without a flat surface and a crystalline corner. This shape can be almost spherical, or in the shape of a potato or walnut. A few particles, especially the larger ones, also show cracks like dry mud. Smaller particles typically have a less spherical shape and a more pronounced crack.

In other cases, the percentage of particles having a spherical shape is small. In this case, more of the larger particles have a less spherical shape and exhibit extremely significant cracks. Again, in this case, all of the particles are composed of a plurality of microcrystalline particles having a particle size much smaller than those of the particles.

The morphology with more globularity was observed with smaller diamines, while the morphology with more pronounced cracks was observed with larger diamines. Similarly, this can be explained by the mechanism of absorption and rupture of the dicarboxylic acid particles in the reaction with the diamine to cause particle breakage. This expansion and hence the rupture of the larger diamine will be more pronounced.

If the microcrystalline particles have a small particle size, the particles are typically far more Large particle size, even for most smaller particles.

Suitably, the salt particulate material has a particle size distribution with a d10 of at least 20 μm. Also suitably, the particulate material has a particle size distribution with a d90 of at most 1000 μm and optionally an intermediate particle size (d50) of 50-600 μm. Here, the particle size distribution is measured in accordance with the method of ISO 13320 as described above.

In a preferred embodiment of the diamine/dicarboxylate salt, d10 is in the range of 20-200 μm, and/or d50 is in the range of 50-500 μm, and/or d90 is in the range of 200-1000 μm. . More specifically, the d10 of the diamine/dicarboxylate particles is in the range of 20-200 μm, the d50 is in the range of 50-500 μm, and the d90 is in the range of 200-1000 μm.

Also preferably, the polycrystalline particles have a particle size distribution having a span of at most 5, preferably at most 2.5, which is defined by the ratio of (d84-d16) / d50. The advantages are more homogeneous products, less fines, and better flow.

A further feature of the diamine/dicarboxylate obtainable by the process according to the invention is that the particulate material generally has a low degree of compression. The degree of compression is determined by comparing the aerated bulk density (ABD) and the compacted bulk density (TBD). Suitably, the degree of compression expressed as a ratio of (TBD-ABD) / TBD * 100% is at most 35%, wherein ABD is a gas-filled bulk density and TBD is a compacted bulk density, both measured according to the method of ASTM D6393 .

Salts in accordance with the present invention suitably comprise a salt of one or more of the dicarboxylic acids and one or more diamines, and any combination thereof, as further described above.

Some examples include the following combinations: 6T/66; the molar ratio is suitably in the range of 80/20-20/80, for example, 62/38; PA 6T/610; The combination is in the range of 90/10-30/70, for example, 70/30; PA 6T/4T; the molar ratio is suitably in the range of 90/10-10/90, for example, 60/40; and PA 6T/10T; the molar ratio is suitably in the range of 90/10-30/70, for example, 70/30. Here, 4T is a salt mainly composed of 1,4-butanediamine and terephthalic acid. 6T is a salt mainly composed of 1,6-hexanediamine and terephthalic acid. 66 is a salt mainly composed of 1,6-hexanediamine and adipic acid. 610 is a salt mainly composed of 1,6-hexanediamine and adipic acid. 10T is a salt mainly composed of 1,10-nonanediamine and terephthalic acid.

More particularly, the salt comprises a salt mainly composed of 1,4-hexane diamine and terephthalic acid and/or a salt mainly composed of 1,6-hexanediamine and terephthalic acid. More particularly, it is mainly 1,4-butanediamine and terephthalic acid, and terephthalic acid is present in an amount of at least 70 mol% of all diacids, and 1,4-butanediamine It is present in an amount of at least 10 mole % of all diamines. More preferably, the salt is anhydrous 4T or 6T salt.

The invention also relates to a polymerization process for the use of such salts for the preparation of polyamines.

The invention is further illustrated by the following examples and comparative experiments.

method Melting temperature

The melting temperature (Tm) was measured by DSC in a N2 atmosphere at a heating and cooling rate of 20 ° C/min according to the method of ISO 11357-3.2, 2009. Here, Tm is the temperature measured by the peak of the melting peak around the first heating.

Aerated Bulk Density (ABD) and Compacted Bulk Density (TBD)

ABD and TBD are by the method of ASTM D6393-08 ("Standard Test Method for Bulk Solids Characterization by Carr Indices", ASTM International, West Conshocken, PA, in accordance with the present invention. DOI: 10.1520/D6393-08) was measured at 20 ° C using a Hosokawa powder tester.

Particle size distribution

The particle size distribution of the particulate material is by laser granulation according to ISO 13320-1, with a Sympatec Helos (H0024) & Rodos device at 20 ° C, with an applied pressure of 0.5 bar, and a 25 mbar tube Measuring pressure measurement within.

Shear test

The fluidity is measured by the method according to ASTM Standard D6773-08 ("Standard Shear Test Method for Bulk Solids Using the Schulze Ring Shear Tester", ASTM International, West Conshocken, PA, DOI: 10.1520/D6773-08). The shear test was carried out using a Schulze Ringshear tester at 20 ° C with a consolidation stress of 3 kPa. The measurement begins immediately after filling the tester.

Pore method

Porosity is measured by a mercury intrusion porosimetry (MIP) experiment performed by a Micromeritics Autopore IV 9505 Pneumatic Apparatus (www.micromeritics.com) from a vacuum to a pressure range of up to 22 Mpa. The samples were held in vacuum for 16 hours prior to measurement. Then, about 0.15 grams of each sample of dry material was transferred to the sample holder and weighed.

Microcrystalline area size

The size of the microcrystalline region was analyzed by Olympus America Inc.'s image analysis software program "Analysis.auto", version 5.0. For this analysis, SEM images taken from surface areas of different particles were used. according to The image portion is selected depending on the surface area of the particle and the size of the microcrystalline particle.

In a typical example, the original image has a size corresponding to a surface area of 15 x 20 μm. This image has 3872 x 3306 pixels. From this image, a representative portion corresponding to a surface area of about 5 x 6 μm is selected. The image has a 1238 x 963 pixel.

After selecting an appropriate portion, the "operation" procedure provided by the software program is implemented as follows: First, as provided by the software, the shading correction is applied using an NxN averaging filter having 6 repetitions and size selection 6. The image is then converted to a negative image. From the converted image, select a representative part.

For a typical sample, the selection is approximately 3.4 x 4.0 μm (3.39 x 3.94 μm).

The selection system converts to a binary image, and for the detection setting, a low value (equal to or close to 0) is applied as a low threshold, and a high value (about 210) is used as a high threshold. In the second image, the contour is applied and corrected by the selection of the "edit image" of the software to remove the artifact. This edited image is used in the Particle Analysis program.

For this analysis, particles having a size of at least 10 pixels were detected. The tested particles are then analyzed for surface area, minimum and maximum diameter, and average diameter. The resulting data is transferred to Excel.

For further analysis used herein, data on the average diameter of individual particles is used. Based on the values of the average diameter of the individual particles, the theoretical volume of each particle is calculated, assuming that the particle system is ideally spherical. Based on this and combined with the results of 3 different particles, the volume-based particle size distribution was calculated and the d10, d50 and d90 values were calculated.

Starting material

Terephthalic acid industrial grade (BP Amoco); 0.05% by weight of water

Adipic acid industrial grade (Rhodia); 0.09 wt% water

Azelaic acid industrial grade (Sigma Aldrich); <0.1% by weight of water

1,4-butane diamine industrial grade (DSM); <0.5% by weight of water

1,6-hexanediamine industrial grade (Sigma Aldrich); <0.5% by weight water

1,10-nonanediamine industrial grade (Sigma Aldrich); <0.5% by weight of water

In the implementation of the conversion of grams into molar, the chemical system is considered 100% pure.

Salt preparation experiment Example I

A mixture of 75 grams of terephthalic acid and 40.4 grams of adipic acid (62/38 mole %) was injected into a 1.0 liter baffled flask attached to a rotary evaporator with a heating The amine was placed in a container, kept under an inert nitrogen atmosphere, and mixed while rotating at 50 rpm. The rotating flask was partially immersed in a water bath and maintained at 60 ° C to remove neutralization heat. The liquid 1,6-hexanediamine (86.6, i.e., a stoichiometric excess of about 2 mole %, or D/DA = 1.02) at 60 ° C was added dropwise to the acid under the fixed spin group at 4 hours. After the addition, the reaction mixture was stirred for another 20 minutes at a water bath temperature of 60 °C by rotary stirring. After the experiment, a salt in the form of a loose powder was obtained.

The compositions listed in Tables 1 and VI and listed in Table 1 were prepared in a manner similar to that described above.

Example II

Example II was prepared as described in Example I, starting with a mixture of 79.3 grams of terephthalic acid and 41.4 grams of sebacic acid (70/30 mole %) and added at 4 hours. 81.3 g of liquid 1,6-hexanediamine formed a loose powder with D/DA=1.026.

Example III

Example III was prepared as described in Example I, starting with 122.5 grams of terephthalic acid and adding a liquid mixture of 52.8 grams of 1,6-hexanediamine and 28.7 grams of 1,4-butanediamine over 2 hours (60/ 40 mol%, which excludes 2.7 g of 1,4-butanediamine in excess, resulting in a loose powder with D/DA=1.026.

Example IV

Example IV was prepared as described in Example I, starting with 111.1 grams of terephthalic acid and adding a liquid mixture of 56.4 grams of 1,6-hexanediamine and 34.6 grams of 1,10-decanediamine over 4 hours (62/ 38 mol%, which excludes 2.0 g of hexamethylenediamine in excess, resulting in a loose powder with D/DA=1.026.

Example V

Example V was prepared as described in Example I starting from 111.1 grams of terephthalic acid and 84.3 grams of liquid 1,6-hexanediamine was added over 5 hours to give a loose powder with D/DA = 1.024.

Sample VI

Example VI was prepared as described in Example I using a 2 liter baffled flask starting with 326.65 grams of terephthalic acid and adding 178.35 grams of liquid 1,4-butanediamine over 3 hours, resulting in D/DA = 1.029 pine powder.

Comparative Experiment A: Preparation of 4T salt in water via aqueous method

A 2000 ml three-necked flask equipped with a reflux condenser, a temperature sensor, and a magnetic stir bar was charged with 300 grams of demineralized water and 104.01 grams of DAB. During 1 minute, 195.99 grams of terephthalic acid (TPA) was added via a funnel attached to the second neck. 4T salt during the addition of TPA It is formed as a white slurry. 600 grams of water was added, and thereafter, the reaction mixture was heated to T = 90 ° C at which temperature 4T salt dissolved. The product was then cooled in a water/ice bath and the cooled slurry was filtered on a Büchner funnel. The mother liquor was mixed with 800 ml of ethanol and the precipitated salt was collected on the same Büchner funnel. The leak cake was washed with 200 ml of ethanol. After the air was passed through the filter cake for 16 hours, the product was mixed to homogenize the two precipitate fractions and dried under vacuum (50 mbar absolute pressure) at 40 ° C for 3 hours. The product had a 283 ° C melting point as determined by DSC.

a) In the case where more than two diamines are used, in order to calculate the composition of the copolymerized decylamine, the excess of diamine is regarded as the lowest molar mass of the diamine in the diamine mixture, and is not included in the molar ratio composition calculation. .

Table 2 shows an overview of the properties of the 4T salt of Example VI and the 4T salt of Comparative Experiment A (CE-A). Photomicrographs of these materials are shown in the attached drawings.

The results not only show the difference in particle size distribution and flow behavior, but also Crystal form is also shown. EX-VI shows a narrow particle size distribution with relatively high d10 and low span, and low compression, while CE-A shows a wider particle size distribution with lower d10 and higher span, and higher compression. The difference in particle size distribution and compression is less than the porosity measurement. Most of the pores are found in the range of 5-500 μm (EX-VI), and the individual pores are 2-600 μm (CE-A), and the pore size of the pores is found to correspond equally to the interparticles. Porosity. EX-VI has a peak at a larger pore size (70 μm), which is higher and narrower (from 20-100 μm) than CE-A. CE-A has a lower but wider pore size distribution with a peak at a lower pore size (10 μm), but still has a significant amount of pores having a size greater than 100 μm.

The different crystal forms are illustrated by the SEM images shown in Figures 1-5.

Figure 1: SEM image of the 4T salt of Comparative Example A.

Figure 2-5: SEM image of the 4T salt of Example VI.

Figure 1 shows an SEM image obtained from the 4T salt of Comparative Example A. The image shows large irregularly shaped particles consisting of a plurality of smaller crystals of relatively large size, individually composed of a limited number of crystals of larger size and relatively flat surface areas. Aside from such larger particles, a large number of small particles are visible, many of which consist of a single crystal or only some crystals. Many of these crystal systems are still in the size range of about 5-10 μm.

Figure 2 shows an SEM image taken of the 4T salt of Example VI. The image shows a large number of particles with a spherical shape. Smaller particles have a less spherical shape. The number of small particles is relatively low.

Figure 3 shows an SEM image taken from one of the selected areas of the SEM image of Figure 2, highlighting particles having a spherical shape. Particle effect with dry mud cracks Can be seen.

Figure 4 shows an SEM image taken from one of the selected areas of the SEM image of Figure 3, highlighting the surface area of the spherical particles. On the surface of the particles, many small crystal grains are visible.

Figure 5 shows an SEM image taken from another selected region of the SEM image of Figure 2, highlighting a portion of the particles having a spherical shape and smaller particles having a more irregular shape. Compared to the spherical particles of Figure 3, the latter particles show a more severe cracking effect like a dry mud.

Example VI Microcrystalline Area Size

For the salt of Example VI, the particle size distribution of the microcrystalline region is determined by the surface on the particle and the interior of the particle. For the latter, cross-cut particles are used. Figures 6-14 illustrate the different steps of the analysis procedure, starting with the SEM image (Figure 6) inside the salt particles of Example VI, and the individual SEM images of the salt particles (Figure 10). The results are presented in Table 3.

Figure 6-9: Image of the microcrystalline region inside the 4T particles following the different steps of the particle size analysis.

Figure 10-13: Image of the microcrystalline region outside the 4T particle following the different steps of the particle size analysis.

Figure 6 shows the original SEM image of the 4T salt of Example VI showing the microcrystalline regions inside the particles.

Figure 7 shows one of the choices of Figure 6, where the image has been optimized for comparison and shading correction has been applied.

Figure 8 shows one of the choices of Figure 7, in which the image has been reversed and the contrast is further optimized.

Figure 9 shows one of the choices of Figure 8, where the image has been binarized, edited, and available for particle size analysis.

Figure 10 shows an SEM image of the 4T salt of Example VI showing the microcrystalline regions on the interior of the particles. The SEM image has been optimized for comparison and shading correction has been applied.

Figure 11 shows a selection of Figure 10 in which the image has been inverted and the comparison is further optimized.

Figure 12 shows the same selection as in Figure 8, where the image has been binarized.

Figure 13 shows one of the alternatives of Figure 12 in which the image is edited and available for particle size analysis.

Examples VII and VIII

Examples VII and VIII repeat Example VI, but the terephthalic acid used is different. For Example VII, a special grade with a narrow particle size distribution and a small intermediate particle size was used. For Example VII, a special grade is also used which also has a narrow particle size distribution but a larger intermediate particle size. In the second case, free flowing particles are obtained. Special grades of terephthalic acid (referred to as Comparative Experiments B and C) and particle size distributions and vanes of Examples VII and VIII The results of the fluidity of Examples VII and VIII are shown in Table 4.

The results show that in addition to the fact that the size or at least a majority of it is systematically increased, the particle size distribution of the terephthalic acid starting material is directly reflected in the particle size distribution. This is the dimension of the particle size increase combined with the particle size distribution. This can be interpreted as absorbing the diamine and reacting with the dicarboxylic acid, thereby expanding the dicarboxylic acid particles without breaking it. At the same time, the density is significantly reduced, the most for the EX VIII system, but the compression is still very low. The lower density may be due to the lower intrinsic density of the salt compared to the acid and due to the small spacing between the small cracks within the particle and the microcrystalline particles. The shear test results show that both materials are free flowing.

Example IX

A mixture of adipic acid (ranging from 25 to 100 kg per batch) and terephthalic acid (ranging from 350 to 425 kg per batch) was injected into a 3000 liter drum dryer. After inerting with nitrogen, a mixture of molten (100%, industrial grade) 1,4-butanediamine (25-100 kg) and 1,6-hexanediamine (200-275 kg) at 50 ° C is attached to After 4 hours, the solid acid was sprayed at a large pressure through a perforated plate dispenser while rotating the entire dryer material. The product temperature was measured in time using the PT-100 element inside the dryer, and the dryer contents were maintained below 80 °C by cooling through the dryer wall. The salt obtained had a free flowing crystalline white powder appearance after another hour of feeding and mixing.

Example X

A mixture of adipic acid (range 2.5 to 10 kg per batch) and terephthalic acid (range 35 to 42.5 kg per batch) was injected into a 180 liter conical dryer with a spiral stirrer. After inerting with nitrogen, first (100%, industrial grade) 1,4-butanediamine (2.5-10 kg), then (100%, industrial grade) 1,6-hexanediamine (20-27.5 kg) Spray the solid acid at atmospheric pressure through a tubular (Swazeloc 1/8") dispenser at about 1.5 to 2 hours while stirring the reaction mass with a spiral stirrer. The product temperature is used in time with the dryer. The PT-100 component was measured and the dryer contents were maintained below 65 ° C by cooling through the dryer wall. The feed was heated to 150 ° C under nitrogen and after cooling, the salt obtained had a free flowing crystalline white powder appearance. The same procedure was repeated several times using a premixed amine mixture of 1,4-butanediamine (2.5-10 kg) and (100%, technical grade) 1,6-hexanediamine (20-27.5 kg), resulting in extreme Smaller free flowing crystalline white powder.

Example XI

Terephthalic acid (45 kg) was injected into a 180 liter conical dryer with a spiral stirrer. a mixture of (100%, technical grade) 1,4-butanediamine (2.5-10 kg) and (100%, industrial grade) 1,6-hexanediamine (20-27.5 kg) after inerting with nitrogen It is sprayed to the solid acid at atmospheric pressure via a 4-tube (Swazeloc 1/8") dispenser at about 1.5 to 2 hours while stirring the reaction mass with a spiral stirrer. The product temperature is used in time with the dryer. The PT-100 component was measured and the dryer contents were maintained below 65 ° C by cooling through the dryer wall. After another 1 hour of dosing and mixing, the salt obtained had a free flowing crystalline white powder appearance.

Example XII

A mixture of adipic acid (range 0.6 to 2.7 kg per batch) and terephthalic acid (range 9.3-11.3 kg per batch) was injected into a 50 liter DRAIS plough mixer. a mixture of (100%, technical grade) 1,4-butanediamine (0.6-2.7 kg) and (100%, industrial grade) 1,6-hexanediamine (5.4-7.4 kg) after inerting with nitrogen It is sprayed to the solid acid at atmospheric pressure via a single (Swazeloc 1/8") tube at about 1 hour, while stirring the reaction material with a plough mixer. The product temperature is used in time to insert the coulter into the dryer. The PT-100 component was measured and the dryer contents were maintained below 70 °C by cooling through a mixer. After an additional 1 hour of feeding and mixing, the salt obtained had a free flowing crystalline white powder appearance.

Example XIII

Mixture of adipic acid (range 0.8 to 3.3 kg per batch), terephthalic acid (range 11.6 to 14.2 kg per batch) and benzoic acid (range 0.1 to 0.6 kg per batch) is injected to 100 In the drum of the liter drum dryer. After inerting with nitrogen, a mixture of 1,4-butanediamine (0.8-3.3 kg) and 1,6-hexanediamine (6.6-9.2 kg) at a temperature of 50 ° C (100%, industrial grade) Sprayed to the solid acid at atmospheric pressure via a 4-fold (Swazeloc 1/8") tube dispenser at about 2 hours while rotating the complete dryer material. The product temperature was used in time for the PT-100 inside the dryer. The components were measured and the dryer contents were maintained below 80 ° C by cooling through the dryer wall. After an additional 1 hour of dosing and mixing, the salt obtained had a free flowing crystalline white powder appearance.

Figure 1: SEM image of the 4T salt of Comparative Example A.

Figure 2-5: SEM image of the 4T salt of Example VI.

Figure 6-9: Image of the microcrystalline region inside the 4T particles following the different steps of the particle size analysis.

Figure 10-13: Image of the microcrystalline region outside the 4T particle following the different steps of the particle size analysis.

Claims (26)

A process for the preparation of a diamine/dicarboxylate comprising the steps of contacting a diamine with a dicarboxylic acid to provide a reaction mixture and wherein the diamine reacts with the dicarboxylic acid to form a diamine/dicarboxylate Wherein (a) the dicarboxylic acid comprises an aromatic dicarboxylic acid; (b) the dicarboxylic acid is provided in powder form; (c) the diamine is provided in liquid form; (d) the system of the contacting is carried out By gradually applying the diamine liquid to the dicarboxylic acid powder while maintaining the dicarboxylic acid powder in a continuously moving state; (e) the reaction mixture is directly maintained in a continuous moving state for a period of time after the administration is completed; (d) and (e) are carried out at temperatures above 0 ° C and below the owner: the boiling temperature of the diamine and the dicarboxylic acid, the diamine/dicarboxylate, and any intermediate reaction products a melting temperature, and (g) in (d) and (e), the reaction mixture contains up to 5% by weight of water relative to the total weight of the diamine and the dicarboxylic acid, wherein the diamine is different A mixture of amines, and wherein the process is carried out in a low shear mixer. The method of claim 1, wherein the diamine and the dicarboxylic acid in the reaction mixture are present in a molar ratio of diamine to dicarboxylic acid in the range of from 0.9 to 1.1. The method of claim 1 or 2, wherein the dicarboxylic acid is a mixture of one of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid. The method of claim 3, wherein the mixture of the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid is a dry blend of the solid particles of the aliphatic dicarboxylic acid and one of the solid particles of the aromatic dicarboxylic acid. Compound. The method of claim 3, wherein the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid are present in a molar ratio of between 90:10 and 10:90. The method of claim 1 or 2, wherein the dicarboxylic acid is composed of 90-100 mol% of an aromatic dicarboxylic acid and 10-0 mol% of an aliphatic dicarboxylic acid. The method of claim 1 or 2, wherein the aromatic dicarboxylic acid comprises isophthalic acid, terephthalic acid, or naphthalene dicarboxylic acid, or any combination thereof. The method of claim 3, wherein the aliphatic dicarboxylic acid comprises adipic acid and/or sebacic acid. The method of claim 1 or 2, wherein the diamine comprises an aliphatic diamine having 4 to 12 carbon atoms. The method of claim 9, wherein the diamine comprises 1,4-butanediamine and/or hexamethylenediamine. The method of claim 1 or 2, wherein the diamine and the dicarboxylic acid are contacted by spraying or dropping the diamine onto the mobile dicarboxylic acid powder. The method of claim 1 or 2, wherein the diamine and the dicarboxylic acid are in a drum mixer, a coulter mixer, a conical mixer, and a planetary screw mixer. , or contact and mixing in a fluidized bed reactor. The method of claim 1 or 2, wherein the diamine and the dicarboxylic acid are contacted at a temperature between 0 ° C and the boiling temperature of water. The method of claim 1 or 2, wherein the diamine is reacted with the dicarboxylic acid to form the diamine/dicarboxylate to cause neutralization and removal of the heat via a heat exchanger. The method of claim 1 or 2, wherein the dicarboxylic acid powder has a particle size distribution measured by the method according to ISO 13320, which has a d10 of at least 15 μm, a d90 of at most 1000 μm, and has 40 Intermediate particle size (d50) in the range of -500 μm. The method of claim 15, wherein the dicarboxylic acid powder has a particle size distribution having a span of at most 5, which is defined by a ratio of (d84-d16) / d50. a diamine/dicarboxylate derived from a dicarboxylic acid comprising an aromatic dicarboxylic acid and a diamine consisting of a mixture of different aliphatic diamines, wherein the salt is One of the particulate materials is obtained by the method of any one of claims 1 to 16. A salt according to claim 17, wherein the salt is an anhydrous salt which comprises less than 0.5% by weight of water relative to the total weight of the salt. A salt according to claim 17 or 18, wherein the salt is defined by a shear stress according to ASTM D6773, a consolidation stress, σ1, a ratio of unconstrained yield strength, σc, (ffc) The fluidity is at least 10. The salt of claim 17 or 18, wherein the salt is a particulate material composed of polycrystalline particles comprising microcrystalline particles, The microcrystalline particles have a particle size distribution which is measured by software support analysis of the SEM image obtained from the surface area of the particle, which has a volume-based d90 of at most 5 μm. The salt of claim 17 or 18, wherein the salt is a particulate material composed of polycrystalline particles, wherein the polycrystalline particles have a particle size distribution by ISO 13320 The method measures a d10 of at least 20 μm, a d90 of at most 1000 μm, and an intermediate particle size (d50) in the range of 50-600 μm. The salt of claim 17 or 18, wherein the d10 is in the range of 20-200 μm, the d50 is in the range of 50-500 μm, and the d90 is in the range of 200-1000 μm. The salt of claim 17 or 18, wherein the polycrystalline particles have a particle size distribution having a span of at most 5, preferably at most 2.5, which is at a ratio of (d84-d16)/d50 definition. The salt of claim 17 or 18, wherein the particulate material has a compressibility of at most 35%, expressed as a ratio of (TBD-ABD) / TBD * 100%, wherein ABD is a gas-filled bulk density, And TBD is a compacted bulk density, both measured by the method according to ASTM D6393. The salt of claim 17 or 18, wherein the salt comprises a salt mainly composed of 1,4-butanediamine and terephthalic acid and/or 1,6-hexanediamine and terephthalic acid. Main salt. A method of preparing polyamide, comprising the steps of: contacting a diamine with a dicarboxylic acid without using an organic solvent or a low temperature medium to provide a reaction mixture and wherein the diamine is reacted with the dicarboxylic acid to form a diamine/dicarboxylate wherein (a) the dicarboxylic acid comprises an aromatic dicarboxylic acid; (b) the dicarboxylic acid is provided in powder form; (c) the diamine is provided in liquid form; d) the contacting is carried out by gradually applying the diamine liquid to the dicarboxylic acid powder while maintaining the dicarboxylic acid powder in a continuously moving state; (e) the reaction mixture is directly maintained after the administration is completed. The moving state is for a period of time; (f) (d) and (e) are carried out at a temperature higher than 0 ° C and lower than the following owners: boiling temperature of the diamine and the dicarboxylic acid, the diamine/dicarboxylate And the melting temperature of any intermediate reaction product, and (g) in (d) and (e), the reaction mixture comprises up to 5% by weight of water relative to the total weight of the diamine and the dicarboxylic acid, wherein The diamine is composed of a mixture of different diamines, and wherein the aforementioned step of forming the diamine/dicarboxylate is carried out in a low shear mixer; and the salt is polymerized to form the polyamine.