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MXPA00010536A - Method for producing high melting point crystals of phenoxypropionic acid derivative - Google Patents

Method for producing high melting point crystals of phenoxypropionic acid derivative

Info

Publication number
MXPA00010536A
MXPA00010536A MXPA/A/2000/010536A MXPA00010536A MXPA00010536A MX PA00010536 A MXPA00010536 A MX PA00010536A MX PA00010536 A MXPA00010536 A MX PA00010536A MX PA00010536 A MXPA00010536 A MX PA00010536A
Authority
MX
Mexico
Prior art keywords
crystals
melting point
heating
ethyl
quizalofop
Prior art date
Application number
MXPA/A/2000/010536A
Other languages
Spanish (es)
Inventor
Masami Yasukawa
Shinji Kuwahara
Original Assignee
Nissan Chemicalindustries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Chemicalindustries Ltd filed Critical Nissan Chemicalindustries Ltd
Publication of MXPA00010536A publication Critical patent/MXPA00010536A/en

Links

Abstract

A method for producing high melting point crystals, which is characterized by heating ethyl=(R)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate in the form of low melting point crystals, or low melting point crystals and high melting point crystals, within a range of from 50°C to lower than the melting point of the low melting point crystals.

Description

METHOD FOR PRODUCING HIGH FUSION POINT CRYSTALS OF A PHENOXIPROPIONIC ACID DERIVATIVE TECHNICAL FIELD This invention relates to a method for producing high melting point crystals (hereinafter, β crystals) of ethyl (R) -2- [4- (6-chloro-2-quinoxalyloxy) phenoxy] propionate (in which successive, quizalofop-p-ethyl) and β-crystals produced in this way.
BACKGROUND OF THE INVENTION It is known that quizalofop-p-ethyl, which is useful as an active ingredient for herbicides, has two types of crystalline forms; that is, crystals of low melting point (hereinafter, crystals a) and crystals ß. JP-B-4-76721 discloses that ß crystals can be produced by gradually cooling a solution having quizalofop-p-ethyl dissolved in a solvent, stirring it and maintaining it at a crystallization temperature, and the β-crystals produced are those having agglomerated crystallites of at least 1 μm, so, in some cases, the transfer of the solvent mixture, or the filtration and drying of the precipitated crystals, are difficult.
BRIEF DESCRIPTION OF THE INVENTION An objective of this invention is to provide ß crystals that are easy to handle on an industrial scale and a method for their production. This invention provides a method for producing β crystals, which is characterized by heating quizalofop-p-ethyl in the form of crystals α, or crystals α and β crystals, within a scale of 50CC to less than the melting point of crystals α, and by ß crystals produced by said method. The heating can be carried out by heating in contact with an inert gas at high temperature (hereinafter, gas-solid heating method), heating with mixing in a solid state (hereinafter, method of heating solids) or heating in suspension with a hardly soluble solvent (hereinafter, suspension heating method). The gas-solid heating method can be, for example, a method in which the quizalofop-p-ethyl is charged in an apparatus equipped with a gas-solid contact function, such as a pneumatic conveying dryer, a dryer of fluidized bed, a circulating dryer or a hot air dryer; and a high temperature gas, such as hot air or hot nitrogen, is insufflated to be treated with heat. The solids heating method can be, for example, a method in which the quizalofop-p-ethyl is charged in an apparatus equipped with a heating medium, such as a jacketed kneader, a stirrer, a screw conveyor with a sleeve or a conical dryer, and provided with a mixing function, and heated and mixed for a predetermined period. The suspension heating method can be, for example, a method in which quizalofop-p-ethyl is charged to a hardly soluble solvent, such as water or ethylene glycol, and heated in suspension. The heating can generally be carried out at a temperature ranging from 50 ° C to less than the melting point of the crystals, preferably 65 ° C, less than the melting point of the crystals a. The heating time depends, in general, on the heating temperature and is required until the crystals have substantially disappeared. For example, obtaining ß crystals takes at least 100 hours when the heating is carried out at 60 ° C and, for a few hours, when the heating is carried out at 70 ° C. After the a crystals have been converted to β crystals by heating, cooling or cooling followed by filtration in the suspension, the suspension heating method is carried out to obtain β crystals. In the solid-gas heating method and in the solids heating method, the β-crystals can be obtained in a solid state and can be used as they are, or after being sprayed, for example, for the production of an aqueous suspension concentrated In addition, in the gas-solid heating method or in the solids heating method, if quizalofop-p-ethyl is used mainly in the form of crystals a produced by the crystallization method, the resulting β crystals will be obtained in the form of powder without forming a solid block in the aforementioned apparatus, whereby high productivity can be maintained. In that case, it is preferred to use quizalofop-p-ethyl mainly in the form of crystals to which they do not substantially contain any solvent for crystallization. JP-B-2-214504 discloses that crystals obtained as a wet product by a crystallization method can sometimes be converted to β crystals when they are dried at a temperature above 70 ° C for at least 5 hours. However, if that moist product containing a solvent for crystallization is used, dissolution by the solvent occurs during heating, and the product is likely to be a solid added to the apparatus, so that the industrial process is practically difficult. In the suspension heating method, extraction of the hardly soluble solvent may sometimes be necessary. For example, when the sparingly soluble solvent is water, sometimes a drying step may be required. However, in case an agricultural chemical composition in aqueous suspension is to be obtained, drying will not be necessary, depending on the concentration in weight of the suspension. Also, by the suspension heating method, the dispersed state in the apparatus can be maintained excellently during the heating operation, whereby the control of the temperature of the quizalofop-p-ethyl is easy and ß-uniform crystals can be efficiently produced. . In addition, the β-crystals formed by the suspension heating method are excellent in terms of filtration properties and easy to dry. Now, a method for obtaining desired β crystals will be described by means of the suspension of the raw material in water, which is the solvent that is difficult to dissolve and industrially cheap. That is, the quizalofop-p-ethyl in the form of crystals a, or crystals a and crystals β, is suspended in water, generally in an amount ranging from 0.1 to 60% by weight, preferably from 1 to 60% by weight, and the suspension is maintained at a temperature ranging from 50 ° C to below the melting point of the crystals a until the crystals substantially disappear, preferably at a temperature of 65 ° C below the melting point of the crystals. a for a period of 10 minutes to 48 hours. It is then cooled to a temperature at which filtration can usually be performed, usually no more than 50 ° C, preferably 40 ° C maximum, followed by filtration to collect the crystals. When the crystals have been completely converted to β-crystals, drying of the crystals at a temperature lower than the melting point of the β-crystals, generally lower than the melting point of the α-crystals, preferably at 65 ° C, can be carried out. ° C maximum.
PREFERRED MODALITY OF THE INVENTION Now, this invention will be described in more detail with reference to the examples. However, it should be clear that this invention is not limited, in any way, to said specific examples. The weight ratio of crystals a and β crystals approximates the area ratio of the respective endothermic peaks obtained by differential scanning calorimetry and, accordingly, the area ratio of the respective endothermic peaks was obtained.
EXAMPLE 1 In a 20 I double-screw, U-shaped hopper mixer, 20 kg of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged and mixed. Hot water was circulated in the jacket to raise the temperature to 70 ° C. Four hours later, the differential scanning calorimetry of quizalofop-p-ethyl was carried out, whereby it was confirmed that the entire amount had been converted to β crystals.
EXAMPLE 2 In the same manner as in Example 1, the heating was carried out at 65 ° C for 16 hours and then the differential scanning calorimetry of quizalofop-p-ethyl was carried out, by which it was confirmed that the entire quantity had been converted to ß crystals.
EXAMPLE 3 In a 10 I shake dryer, 5 kg of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged and mixed. Hot water was circulated in the jacket to raise the temperature to 72.5 ° C. Two hours later, the differential scanning calorimetry of quizalofop-p-ethyl was carried out, by which he confirmed that the whole quantity had been converted to β crystals.
EXAMPLE 4 In a 5 I conical dryer, 1 kg of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged and mixed. Hot water was circulated in the jacket to raise the temperature to 55 ° C. Two months later, the differential scanning calorimetry of quizalofop-p-ethyl was carried out, by which it was confirmed that the entire amount had been converted to β crystals.
EXAMPLE 5 In a 10 I instantaneous conical dryer, 3 kg of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged, and hot air was blown in to raise the temperature to 70 ° C. Four hours later, the differential scanning calorimetry of quizalofop-p-ethyl was performed, by which it was confirmed that the entire amount had been converted to β crystals.
EXAMPLE 6 In the same manner as in example 5, the heating was carried out at 65 ° C for 16 hours. Then the differential scanning calorimetry of quizalofop-p-ethyl was carried out, by which it was confirmed that the whole quantity had been converted to β crystals.
EXAMPLE 7 In a 5 I fluidized dryer, 1 kg of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged and hot air was blown in to raise the temperature to 70 ° C. Four hours later, the differential scanning calorimetry of quizalofop-p-ethyl was carried out, by which it was confirmed that the entire amount had been converted to β crystals.
EXAMPLE 8 In a 2 I jacketed reaction flask, 60 g of quizalofop-p-ethyl crystals containing 0.2% by weight of β-crystals, as well as 240 g of water, were charged to prepare a 20% suspension solution. % in weigh. Hot water was circulated in the jacket and the suspension solution was heated to 72.5 ° C and stirred. Two hours later, a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and drying, after which the differential scanning calorimetry was carried out, whereby it was confirmed that the whole quantity had been converted to crystals ß. Subsequently, the hot water was removed from the jacket and the suspension solution mentioned above was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration at room temperature and dried at about 55 ° C. Then the differential scanning calorimetry was carried out, by which it was confirmed that the whole quantity had been preserved as ß crystals.
EXAMPLE 9 In a 2 I jacketed reaction flask, 120 g of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals were charged, as well as 180 g of water, to prepare a suspension solution at 40 ° C. % in weigh. Hot water was circulated in the jacket and the suspension solution was heated to 70 ° C and stirred. Twenty hours later, a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried at 45 ° C. Subsequently, differential scanning calorimetry was carried out, by which it was confirmed that the entire quantity had been converted to β crystals.
EXAMPLE 10 In a 2 I jacketed reaction flask, 40 g of quizalofop-p-ethyl crystals containing 10% by weight of β crystals were charged, as well as 240 g of water, to prepare a suspension solution at approximately 14% by weight. Hot water was circulated in the jacket and the suspension solution was heated to 70 ° C and stirred. Four hours later, a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried. Subsequently, the differential scanning calorimetry was carried out, by which it was confirmed that the whole quantity had been converted to ß crystals. The hot water was then removed from the jacket and the aforementioned suspension solution was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried at about 50 ° C. Subsequently, the differential scanning calorimetry was performed, by which it was confirmed that the entire quantity had been preserved as ß crystals.
EXAMPLE 11 In a 2-liter jacketed reaction flask, 15 g of quizalofop-p-ethyl crystals containing 10% by weight of β-crystals, as well as 240 g of water, were charged to obtain a suspension solution at room temperature. % by weight approximately. Hot water was circulated in the jacket and the suspension solution was heated to 70 ° C and stirred. Six hours later, a part of quizalofop-p-ethyl suspended in the solution was collected by filtration and dried. Then, the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been converted to β crystals. Subsequently, the hot water was removed from the jacket and the aforementioned suspension solution was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried at about 55 ° C. Then the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been preserved as ß crystals.
EXAMPLE 12 In the same manner as in example 11, heating was carried out at 65 ° C for 16 hours. Subsequently, a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried.
Then the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been converted to β crystals. Subsequently, the hot water was removed from the jacket and the aforementioned suspension solution was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration at room temperature and dried at about 60 ° C. Then the differential scanning calotry was performed, by which it was confirmed that the whole quantity had been preserved as ß crystals.
EXAMPLE 13 As in example 11, the heating was carried out at 60 ° C for three days. Then a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried. Subsequently, differential scanning calotry was performed, by which it was confirmed that the entire amount had been converted to β-crystals. Then, the hot water was removed from the jacket and the aforementioned suspension solution was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration at room temperature and dried at about 45 ° C. Then the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been preserved as ß crystals.
EXAMPLE 14 In the same manner as in example 11, the heating was carried out at 67.5 ° C for 10 hours. Subsequently, a part of the quizalpfop-p-ethyl suspended in the solution was collected by filtration and dried. Then the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been converted to β crystals. Then, the hot water was removed from the jacket and the aforementioned suspension solution was cooled. After cooling, the quizalofop-p-ethyl suspended in the solution was collected by filtration at room temperature and dried at about 60 ° C. Subsequently, differential scanning calotry was carried out, by which it was confirmed that the entire amount had been preserved as ß crystals.
EXAMPLE 15 In a 1 000-liter shake tank, 25 kilograms of quizalofop-p-ethyl crystals containing 0.2% by weight of β crystals, as well as 475 kilograms of water were loaded to prepare a suspension solution to the 5% by weight. Hot water was circulated in the jacket and the suspension solution was heated to 70 ° C and stirred. Eight hours later, a part of the quizalofop-p-ethyl suspended in the solution was collected by filtration and dried. Then the differential scanning calotry was carried out, by which it was confirmed that the whole quantity had been converted to β crystals. Then, the aforementioned suspension solution was subjected to filtration by means of a 65 liter centrifugal separator. The product was dried under vacuum at 60 ° C by means of a 600 liter conical drier to obtain a dry product of ß-quizalofop-p-ethyl crystals.

Claims (6)

NOVELTY OF THE INVENTION CLAIMS
1. - A method for producing crystals with a high melting point, characterized by the heating of ethyl (R) -2- [4- (6-chloro-2-quinoxalyloxy) phenoxy] -propionate in the form of crystals of low melting point , or low melting point crystals and high melting point crystals, on a scale that varies from 50 ° C to less than the melting point of the low melting point crystals.
2. The method according to claim 1, further characterized in that the heating is heating in contact with an inert gas at high temperature, heating with mixing in the solid state, or heating in suspension with a solvent hardly soluble.
3. The method according to claim 1, further characterized in that the heating is heating in suspension with a solvent hardly soluble.
4. The method according to claim 3, further characterized in that the hardly soluble solvent is water.
5. The method according to claim 4, further characterized in that from 1 to 60% by weight, based on water, of (R) -2- [4- (6-chloro-2-quinoxalyloxy) phenoxy is suspended. ] ethyl propionate.
6. Crystals of high melting point produced by means of the method defined in claim 1.
MXPA/A/2000/010536A 1998-04-28 2000-10-26 Method for producing high melting point crystals of phenoxypropionic acid derivative MXPA00010536A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10/118456 1998-04-28

Publications (1)

Publication Number Publication Date
MXPA00010536A true MXPA00010536A (en) 2002-05-09

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