JP2002275132A - Method for producing high purity quaternary ammonium inorganic acid salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high purity quaternary ammonium inorganic acid salt not containing a halogen anion or an organic carboxylic acid as a byproduct at a low cost. SOLUTION: This method for producing a high purity quaternary ammonium inorganic acid salt is characterized by comprising (a) a process of generating the quaternary ammonium inorganic acid salt and an organic carboxylic acid by performing an anion interchange reaction of a quaternary ammonium organic carboxylic acid salt expressed by the following general formula <1> with an inorganic acid in an alcohol as a solvent, (b) a process of generating a byproduct organic carboxylic acid ester having a low boiling point than that of the above alcohol by reacting the above organic carboxylic acid with the above alcohol. (c) a process of removing the above organic carboxylic acid ester to the outside of the reaction system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to quaternary ammonium inorganic acid salts which are used in a wide range of fields as various catalysts such as phase transfer catalysts, electrolytes for aqueous and organic electrolytes, various additives and chemicals. The present invention relates to a method for producing a high-purity quaternary ammonium inorganic acid salt from a quaternary ammonium organic carboxylate.

[0002]

2. Description of the Related Art Conventionally, quaternary ammonium salts are generally
It can be obtained by reacting a tertiary amine with an alkyl halide, dialkyl sulfate or the like under heating.

[0003] The quaternary ammonium inorganic acid salt, which is the desired product, is usually prepared as shown in the following <Methods 1-4>.
Halogen anion (X ⁻ ) of quaternary ammonium halide
With an anion (A ⁻ ) of the corresponding inorganic acid.

[0004] <Method 1> quaternary ammonium halide ^- to, quaternary ammonium hydroxide ^{_{(R 4 N + · X)}} (R 4 N + · OH -) and the post-Reaction 1a], then
Quaternary ammonium hydroxide and an inorganic acid ^(H + A ^-) by the Reaction 1b] neutralizing, the quaternary ammonium inorganic acid salt ^- obtaining ^{_{(R 4 N + · A)}} .

[0005]

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[0006] In the <method-1>, first, a quaternary ammonium hydroxide must be produced by a method using an ion-exchange resin, a method of reacting with an alkali metal hydroxide, or a method of electrochemically reacting. Although methods have been proposed, all of these methods are expensive quaternary ammonium hydroxides and are inferior in economy, and it is difficult to completely remove the halogen anion.

<Method-2> A quaternary ammonium halide (R ₄ N) is prepared in a solvent in which a quaternary ammonium inorganic acid salt is insoluble.
⁺ .X ⁻ ) and an inorganic acid (H ⁺ A ⁻ ) to produce a quaternary ammonium inorganic acid salt (R ₄ N ⁺ .A ⁻ ),
It is obtained by precipitation and separation from the solvent [Reaction 2].

[0008]

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In the <method-2>, it is very difficult to remove the halogen anion in the quaternary ammonium inorganic acid salt as the target substance, and a high-purity product was not obtained.

<Method-3> Quaternary ammonium halide (R ₄ N ⁺ .X ⁻ ) and inorganic acid alkali metal salt (Na ⁺ A)
^- ) To obtain the resulting quaternary ammonium inorganic acid salt (R ₄ N ⁺ .A ⁻ ) by precipitation or extraction [Reaction 3].

[0011]

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In <Method-3>, similarly to <Method-2>,
It is very difficult to remove the halogen anion in the quaternary ammonium salt, and a high-purity product was not obtained.

[0013] <Method -4> quaternary ammonium halides _{^{(R 4 N + · X -}} ) and silver salt of an inorganic acid ^(Ag + A ^-) are reacted to the precipitated silver halide (AgX) was filtered off Then, from the filtrate, a quaternary ammonium inorganic acid salt (R ₄ N ^+.
A ^-) to obtain the reaction 4].

[0014]

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[0015] <Method-4> is suitable for quantitative reaction, but the silver salt is very expensive, economically inferior, and cannot be used industrially.

In addition to the above <methods 1-4>, a dialkyl carbonate is reacted with a tertiary amine to obtain a quaternary ammonium alkyl carbonate, and then reacted with an inorganic acid to form a quaternary ammonium inorganic acid. Although there is a method of obtaining a salt, there is a risk that a halide may be mixed into a target product because the dialkyl carbonate as a raw material is expensive and the dialkyl carbonate is produced from phosgene and an alcohol.

Further, an organic carboxylic acid ester is reacted with a tertiary amine to obtain a quaternary ammonium organic carboxylate, and then reacted with an inorganic acid salt in a polar solvent to form a quaternary ammonium inorganic acid salt. In the method of obtaining, the point that the reaction rate between the organic carboxylic acid ester and the tertiary amine is slow was improved by the combined use of a reaction accelerator and the like, but the by-product organic carboxylic acid was mixed into the target product, and the yield was low. Rate is low,
The economy was poor.

As described above, the conventional method has various problems, and a method for economically producing a high-purity quaternary ammonium inorganic acid salt has been demanded.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-purity quaternary ammonium inorganic acid salt containing no halogen anion or by-product organic carboxylic acid, which can solve the above-mentioned problems, at a low cost. It is to provide a method of manufacturing.

[0020]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have produced a high-purity quaternary ammonium inorganic acid salt containing no halogen anion or by-product organic carboxylic acid. Thus, the present invention has been completed.

That is, the present invention provides a) a quaternary ammonium inorganic carboxylate represented by the following general formula <I> and an inorganic acid by anion exchange reaction in an alcohol which is a solvent. Generating an acid carboxylate and an organic carboxylic acid; b) generating an by-product organic carboxylic acid ester having a boiling point lower than the alcohol by an esterification reaction between the organic carboxylic acid and the alcohol; Removing the carboxylic acid ester out of the reaction system.

[0022]

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In the formula, R ₁ , R ₂ , R ₃ , and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₁ , R ₂ , R ₃ , R
₄ may be the same or different. Also R
COO ^- represents an organic carboxylic acid anion, R represents a hydrogen atom or a methyl group.

The organic carboxylate anion of the quaternary ammonium organic carboxylate represented by the general formula <I> as a starting material is a formate anion and / or an acetate anion.

The alcohol used in the present invention is at least one selected from the group consisting of aliphatic alcohols having 1 to 3 carbon atoms, such as methanol, ethanol, and the like.
n-propanol and isopropanol.

The next step utilizing the boiling point difference between an organic carboxylic acid produced by an anion exchange reaction between a quaternary ammonium organic carboxylate represented by the general formula <I> and an inorganic acid, which is a starting material, and an alcohol In consideration of the above, methanol and / or ethanol are preferred.

The alcohol used in the present invention is a quaternary ammonium organic carboxylate represented by the general formula <I>:
1 to 20 parts by mass is used relative to parts by mass.

As an example, the starting material, quaternary ammonium organic carboxylic acid, can be prepared by using a polar solvent such as alcohol in a pressure vessel as necessary, as shown in the following [Reaction-5]. Under an active gas atmosphere, a tertiary amine (R ₁ R ₂ R ₃ N) and an organic carboxylic acid ester (RCO
OR ₄ ) at a temperature of 100 to 160 ° C. A small amount of a removable organic carboxylic acid, water or the like may be added as a reaction accelerator.

[0029]

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In the formula, R ₁ , R ₂ , R ₃ , and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₁ , R ₂ , R ₃ , R
₄ may be the same or different. Also R
COO ^- represents an organic carboxylic acid anion, R represents a hydrogen atom or a methyl group.

The above R ₁ , R ₂ , R ₃ and R ₄ have 1 to 1 carbon atoms.
Examples of the alkyl group 3 include a methyl group, an ethyl group, and a propyl group.

The organic carboxylate anion RC
Examples of OO ⁻ include a formate anion and / or an acetate anion.

The quaternary ammonium organic carboxylate represented by the general formula <I>, which is a starting material, is used in the above [Reaction-5].
Besides, it can be synthesized from quaternary ammonium carbonate, quaternary ammonium bicarbonate, quaternary ammonium hydroxide, quaternary ammonium carbonate, etc., and the present invention is not limited at all by [Reaction-5]. .

The quaternary ammonium organic carboxylate represented by the general formula <I>, which is a starting material of the present invention, includes, for example, tetramethylammonium-formate, trimethylethylammonium-formate, and trimethylpropylammonium-formate. Salt, triethylmethylammonium-formate, tetraethylammonium-formate, tripropylmethylammonium-formate, tripropylethyl-
Formate, dimethyldiethylammonium-formate, diethyldipropylammonium-formate, dipropylmethylethylammonium-formate, dimethylethylpropylammonium-formate, diethylmethylpropylammonium-formate, tetramethylammonium-acetate, Trimethylethylammonium-acetate, trimethylpropylammonium-acetate, triethylmethylammonium-acetate, tetraethylammonium-acetate, tripropylmethylammonium-acetate, tripropylethyl-acetate, dimethyldiethylammonium-acetate, diethyl Dipropylammonium-acetate,
Examples include dipropylmethylethylammonium-acetate, dimethylethylpropylammonium-acetate, and diethylmethylpropylammonium-acetate.

The inorganic acid used in the present invention is perchloric acid,
It is one kind selected from the group consisting of borofluoric acid and hexafluorophosphoric acid, and is 1.0 to 1.0 mol per mol of the quaternary ammonium organic acid salt represented by the general formula <I> as a starting material.
2.0 moles are used. Preferably, there is a small excess of greater than 1.0 mole to less than 1.1 mole.

In the present invention, first, in a solvent alcohol, a quaternary ammonium organic carboxylate represented by the general formula <I> and an inorganic acid undergo an anion exchange reaction, and a compound represented by the general formula <
A quaternary ammonium inorganic acid salt represented by I> is generated, and an organic carboxylic acid is released. Since the inorganic acid used in the present invention is a sufficiently strong acid as compared with the organic carboxylic acid, the above-mentioned anion exchange reaction is completed quickly.

Next, the liberated organic carboxylic acid undergoes an esterification reaction with an alcohol as a solvent at ordinary temperature to under heating to produce a by-product organic carboxylic acid ester. further,
The esterification reaction is accelerated by heating, and the esterification reaction proceeds to an equilibrium state.

Since the esterification reaction is promoted in the presence of a strong acid, an inorganic acid, the starting material represented by the general formula <
When a small excess of more than 1.0 mol to less than 1.1 mol of the inorganic acid is used per 1 mol of the quaternary ammonium organic carboxylate represented by I>, the excess inorganic acid acts as a catalyst. , Easier to progress.

In the present invention, since the by-produced organic carboxylic acid ester has a boiling point lower than the boiling point of the alcohol as a solvent, the by-product organic carboxylic acid ester is reacted by refluxing under reduced pressure or normal pressure at normal temperature to heating. Can be distilled out of the system. As the by-product organic carboxylic acid ester is distilled off, the remaining organic carboxylic acid is esterified, and almost all is removed to the outside of the reaction system.

Further, a small amount of the organic carboxylic acid which remains can be removed from the reaction system by crystallization or recrystallization using an alcohol. No carboxylic acid remains, and the desired high-purity quaternary ammonium inorganic acid salt can be obtained.

In the case of the quaternary ammonium formate represented by the general formula <I>, formic acid produced by an anion exchange reaction with an inorganic acid is mixed with an alcohol as a solvent at room temperature due to the reaction activity of formic acid itself. This is preferable because it easily undergoes an esterification reaction to form a formic acid by-product.

Considering the easiness of removing the formate by-product, methanol>ethanol>isopropanol> n-
The order is propanol. The boiling point of methanol or ethanol is particularly preferred because it is lower by at least 20 ° C. than the boiling point of the formic acid ester.

In the case of the quaternary ammonium-acetate represented by the general formula <I>, the esterification reaction between acetic acid generated by an anion exchange reaction with an inorganic acid salt and an alcohol as a solvent is carried out by converting formate into Although slower than when, the reaction can be advanced by adding a small excess of inorganic acid and heating. When methanol is used as the solvent alcohol, the difference in boiling point from the by-produced acetic ester is large, and the removal of the by-produced acetic ester is easier, which is preferable.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below by way of examples. "%" In Examples is "% by mass".
Represents Note that the present invention is not limited by these examples.

Example 1 7.7 g (65 mmol) of tetramethylammonium formate was dissolved in 100 g of methanol as a solvent, and 14.97 g of 42% borofluoric acid as an inorganic acid was dissolved.
(71.5 mmol) was added, and the mixture was stirred at room temperature for 1 hour, and then heated and refluxed under normal pressure at a temperature of 64 ° C to distill off methyl by-product. After distilling off the methyl formate,
After methanol was distilled off under reduced pressure, isopropyl alcohol was added to precipitate crude white crystals of tetramethylammonium-borofluoride, which was separated by filtration.

Next, the crude crystals were obtained by using ethanol.
After recrystallization, filtration and drying under reduced pressure, purified white crystals of tetramethylammonium-borofluoride 9.4
1 g (90% yield) was obtained. The composition is shown in Table 1.

The presence or absence of residual formic acid in the obtained purified crystals was determined by ion chromatography (IC7 manufactured by Yokogawa Electric Corporation).
000), no formic acid remained. Table 2 shows the results.

The obtained purified crystals are derivatized with an organic carboxylic acid using methanol and boron trifluoride diethyl ether complex, and the presence or absence of residual formic acid is determined by gas chromatography (HP589, manufactured by Hewlett-Packard Company).
0), no formic acid remained.
Table 2 shows the results.

Example 2 In Example 1, 17.42 g of 60% hexafluorophosphoric acid (7%) was used in place of the inorganic acid, 42% borofluoric acid.
Except for using 1.5 mmol), 12.96 g (91% yield) of purified white crystals of tetramethylammonium hexafluorophosphate was obtained in the same manner as in Example 1. The composition is shown in Table 1.

The presence or absence of formic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no formic acid remained. Table 2 shows the results.

Example 3 In Example 1, 7.7 g of 60% perchloric acid (71.5 mmol) was used instead of 42% borofluoric acid as an inorganic acid.
l) Purified white crystals of tetramethylammonium-perchlorate were obtained in the same manner as in Example 1 except that l) was used.
4 g (89% yield) were obtained. The composition is shown in Table 1.

The presence or absence of formic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no formic acid remained. Table 2 shows the results.

Example 4 10.5 g (65 mmol) of triethylmethylammonium formate was dissolved in 100 g of methanol as a solvent, and 14.9 g of 42% borofluoric acid as an inorganic acid was dissolved.
7 g (71.5 mmol) were added. Hereinafter, Example 1
11.88 g of purified white crystals of triethylmethylammonium-borofluoride (yield 90)
%). The composition is shown in Table 1.

The presence or absence of formic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no formic acid remained. Table 2 shows the results.

Example 5 In Example 4, 17.42 g of 60% hexafluorophosphoric acid (7.42 g) was used in place of the inorganic acid of 42% borofluoric acid.
14.94 g (88% yield) of purified white crystals of triethylmethylammonium hexafluorophosphate was obtained in the same manner as in Example 4 except that 1.5 mmol) was used. The composition is shown in Table 1.

The presence or absence of formic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no formic acid remained. Table 2 shows the results.

Example 6 The procedure of Example 4 was repeated, except that 60% perchloric acid (71.5 mmol) was used in place of the inorganic acid, 42% borofluoric acid. 12.27 g of purified white crystals of methyl ammonium perchlorate
(93% yield). The composition is shown in Table 1.

For the presence or absence of formic acid in the obtained purified crystals, an ion chromatographic analysis and a gas chromatographic analysis were carried out according to Example 1, but no formic acid remained. Table 2 shows the results.

Example 7 In 100 g of methanol as a solvent, 8.65 g (65 mmol) of tetramethylammonium acetate was dissolved, and 14.97 g of 42% borofluoric acid (71.5 m
mol) was added. Thereafter, in the same manner as in Example 1, 9.4 g (yield 90%) of purified white crystals of tetramethylammonium-borofluoride were obtained. The composition is shown in Table 1.

The presence or absence of acetic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no acetic acid remained. Table 2 shows the results.

Example 8 In Example 7, 17.42 g of 60% hexafluorophosphoric acid (7.42 g) was used in place of the inorganic acid 42% borofluoric acid.
Except for using 1.5 mmol), 12.81 g (yield 90%) of purified white crystals of tetramethylammonium hexafluorophosphate was obtained in the same manner as in Example 7. The composition is shown in Table 1.

The presence or absence of acetic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no acetic acid remained. Table 2 shows the results.

Example 9 In Example 7, 7.7 g (71.5 mmol) of 60% perchloric acid was used in place of 42% borofluoric acid as an inorganic acid.
Except for using l), in the same manner as in Example 7, the purified white crystals of tetramethylammonium-perchlorate 10.1
5 g (90% yield) was obtained. The composition is shown in Table 1.

The presence or absence of acetic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, but no acetic acid remained. Table 2 shows the results.

Comparative Example 1 Tetramethylammonium acetate (8.65 g, 65 mmol) was dissolved in a solvent, acetonitrile (100 g), and 42% borofluoric acid (14.9%) as an inorganic acid was dissolved.
After adding 7 g (71.5 mmol), the mixture was heated and refluxed at a temperature of 81 ° C. for 1 hour, but no methyl acetate was formed. Next, acetonitrile as a solvent was distilled off under reduced pressure. At this time, the residue was a slurry having an acetic acid smell.

Isopropyl alcohol was added to the residue to precipitate a crude white crystal of tetramethylammonium-borofluoride, which was separated by filtration. Then, the crude crystals were recrystallized using ethanol, filtered, and dried under reduced pressure to obtain 9.4 g (yield: 90%) of purified white crystals of tetramethylammonium-borofluoride. . The composition is shown in Table 1.

The presence or absence of acetic acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, and it was confirmed that acetic acid remained. Table 2 shows the results.

Comparative Example 2 Tetramethylammonium butyrate (10.48 g, 65 mmol) was dissolved in 100 g of methanol as a solvent, and 42% borofluoric acid as an inorganic acid was 14.97 g.
g (71.5 mmol), and then at a temperature of 64 ° C., 1
After stirring for a period of time, methanol was distilled off under reduced pressure, and isopropyl alcohol was added to precipitate crude white crystals of tetramethylammonium-borofluoride.
I filtered. Then, the crude crystals were prepared using ethanol,
After recrystallization, filtration and drying under reduced pressure, purified white crystals of tetramethylammonium-borofluoride 9.4
1 g (90% yield) was obtained. The composition is shown in Table 1.

The presence or absence of butyric acid in the obtained purified crystals was analyzed by ion chromatography and gas chromatography according to Example 1, and it was confirmed that butyric acid remained. Table 2 shows the results.

[0070]

[Table 1]

[0071]

[Table 2]

As shown in Table 2, while it was difficult to remove the residual organic carboxylic acid by the conventional method (Comparative Example 1), the method according to the present invention (Examples 1 to 9) was difficult. For example, the organic carboxylic acid did not remain in the target quaternary ammonium inorganic acid salt, and a high-purity quaternary ammonium inorganic acid salt was obtained.

[0073]

According to the production method of the present invention, a quaternary ammonium organic carboxylic acid and an inorganic acid are reacted in an alcohol as a solvent, and then the liberated organic carboxylic acid and an alcohol are esterified. Thus, by-product organic carboxylic acid ester is generated, and the organic carboxylic acid ester is selected to be an organic carboxylic acid ester lower than the boiling point of the alcohol, thereby removing the organic carboxylic acid ester outside the reaction system. As a result, the organic carboxylic acid does not remain in the target quaternary ammonium inorganic acid salt, and a high-purity quaternary ammonium inorganic acid salt can be obtained.

According to the production method of the present invention, a high-purity quaternary ammonium inorganic acid salt can be produced inexpensively and easily.

Claims (10)

[Claims] 1. a) An anion exchange reaction between a quaternary ammonium organic carboxylate represented by the following general formula <I> and an inorganic acid in an alcohol as a solvent to form a quaternary ammonium inorganic acid salt and an organic acid: Generating a carboxylic acid;
b) an esterification reaction between the organic carboxylic acid and the alcohol to produce a by-product organic carboxylic acid ester having a boiling point lower than the boiling point of the alcohol; and c) a step of removing the organic carboxylic acid ester out of the reaction system. A method for producing a high-purity quaternary ammonium inorganic acid salt, comprising: Embedded image (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different. . may also RCOO be ^- represents an organic carboxylic acid anion, R represents a hydrogen atom or a methyl group). 2. The quaternary ammonium organic carboxylate represented by the general formula <I> according to claim 1, wherein the organic carboxylate anion RCOO ⁻ is a formate anion and / or an acetate anion. A method for producing a high-purity quaternary ammonium inorganic acid salt, which is characterized by the following. 3. The high purity quaternary ammonium inorganic acid salt according to claim 1, wherein the alcohol is at least one selected from aliphatic alcohols having 1 to 3 carbon atoms. Production method. 4. The method for producing a high-purity quaternary ammonium inorganic acid salt according to claim 3, wherein the alcohol is methanol and / or ethanol. 5. An alcohol is used in an amount of 1 part by mass based on 1 part by mass of a quaternary ammonium organic carboxylate represented by the general formula <I>.
The method for producing a high-purity quaternary ammonium inorganic acid salt according to any one of claims 1 to 4, wherein the amount is from 20 to 20 parts by mass. 6. The inorganic acid according to claim 1, wherein the inorganic acid is one selected from the group consisting of perchloric acid, borofluoric acid, and hexafluorophosphoric acid. The method for producing a high-purity quaternary ammonium inorganic acid salt according to the above item. 7. An inorganic acid is used in an amount of 1.0 to 1.0 mol per 1 mol of the quaternary ammonium organic carboxylate represented by the general formula <I>.
The method for producing a high-purity quaternary ammonium inorganic acid salt according to any one of claims 1 to 6, wherein the amount is 2.0 mol. 8. The method according to claim 1, wherein the amount of the inorganic acid is more than 1.0 mol and less than 1.1 mol based on 1 mol of the quaternary ammonium organic carboxylate represented by the general formula <I>. The method for producing a high-purity quaternary ammonium inorganic acid salt according to any one of claims 1 to 6. 9. A compound represented by the general formula <I> in a solvent methanol:
Per mole of a quaternary ammonium-acetate represented by the formula, perchloric acid, an inorganic acid selected from borofluoric acid or hexafluorophosphoric acid is added from more than 1.0 mol to less than 1.1 mol, The method for producing a high-purity quaternary ammonium inorganic acid salt according to claim 1, wherein the reaction is carried out within a range from room temperature to reflux temperature. 10. A quaternary ammonium formate salt represented by general formula <I> in a solvent of methanol and / or ethanol, per mol of perchloric acid, borofluoric acid or hexafluorophosphoric acid. 2. The high purity quaternary ammonium inorganic acid salt according to claim 1, wherein the selected inorganic acid is added in excess of 1.0 to less than 1.1 mol and reacted within a range of room temperature to reflux temperature. Method.