JPS6136514B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION This invention relates to an improved process for making aliphatic diperoxy acids having from about 8 to about 16 carbon atoms. Peroxygen bleaches generally and peroxyacid compounds specifically have long been recognized as effective bleaching agents for use where the negative dyeing and fabric damage effects of aggressive halogen-activated bleaches cannot be tolerated. I came here. For example, Canadian Patent No.
See specification No. 632620 (dated January 30, 1962). Because peroxyacid compounds have such interesting properties, it is desirable to produce them in the most economical manner. The prior art teaches how to make peroxy acid compounds in several ways. Namely, "Journal, American Chemical Society" volume 79,
On page 1929 (1957), Parker et al.
A method for producing diperoxy acid by dissolving dibasic acid in sulfuric acid and adding hydrogen peroxide dropwise is disclosed, and US Pat. No. 3,079,411 (dated February 26, 1963)
discloses a process for making long chain aliphatic peroxy acids by combining a fatty acid with an alkanesulfonic acid and then treating it with excess hydrogen peroxide, and U.S. Pat. No. 2,813,896 (November 19, 1957) , the following manufacturing method is described. That is, sulfuric acid and hydrogen peroxide are combined and subsequently treated with a carboxylic acid. As a result of this reaction, at the end of the reaction there is at least 1 mole of sulfuric acid for every 6 moles of water. All of the above-mentioned methods are batch manufacturing methods. Also disclosed is a continuous process for making diperoxyacids. See, eg, US Pat. No. 3,235,584 (Feb. 15, 1966). The patent describes the reaction of halogenated organic acids with alkali metal or alkaline earth metal peroxides to form salts of peroxycarboxylic acids, and is also described in U.S. Pat. No. 3,284,491 (1966). November 8th
(date) discloses the production of peroxyacids in a single liquid phase. Although the prior art teaches several ways of making peroxyacids, the advantages associated with making peroxyacids of the type described above utilize a continuously stirred reactor and utilize sulfuric acid, water, and hydrogen peroxide reaction media. There is no suggestion whatsoever regarding this. The inventors have discovered that in a continuous reactor, aliphatic diperoxy acids can be produced with significantly higher amounts of crystals than can be produced by a batch process. As a result, the increased fraction allows crystals to be collected more easily and economically. It is therefore an object of the present invention to provide a process for the preparation of diperoxy acids with increased crystal size. This and other objects of the invention will become apparent from the description below. In this specification, all percentages and ratios are expressed by weight unless otherwise specified. SUMMARY OF THE INVENTION The present invention relates to a process for making aliphatic diperoxy acids comprising the step of sequentially adding a dibasic acid having from about 8 to about 16 carbon atoms, sulfuric acid, hydrogen peroxide, and water to a stirred reactor. The generated diperoxy acid is
In order to keep the residence time of the reactants constant in the reactor, they are continuously withdrawn. DETAILED DESCRIPTION OF THE INVENTION The process of the invention comprises the step of sequentially adding an aliphatic dibasic acid having from about 8 to about 16 carbon atoms, sulfuric acid, hydrogen peroxide, and water to a stirred reactor. There is. The dibasic acid is peroxidized to a diperoxy acid in the reactor, which then precipitates into crystalline form. This crystalline product is continuously withdrawn from the reactor in order to keep the average residence time of the reactants constant. The actual average residence time can be set by controlling reactant feed rates and product recovery rates. It is therefore possible to vary the average residence time from minutes to hours based on the actual reactor design. From the standpoint of efficiency, the residence time is preferably long enough to achieve a conversion rate of at least 80% of the dibasic acid to diperoxy acid. The liquid composition in the reactor, excluding diacids and diperoxyacids, is critical to the production of diperoxyacids. In the present invention, the liquid composition held in the reactor comprises about 60% to about 80% sulfuric acid;
It has been found preferred to comprise about 0.5% hydrogen peroxide, about 15% hydrogen peroxide, and about 39.5% water.
Furthermore, this liquid composition is mixed with approximately 60% sulfuric acid in the reactor.
Most preferably, the proportions are between about 2% and about 15% hydrogen peroxide, and between about 5% and about 38% water. All components used in the method of the invention are readily available on the market. Hydrogen peroxide can be used in any concentration, preferably from about 35% to about 70%. In contrast, sulfuric acid has approximately 92%
Preferably, it is used at a concentration of 98% to 98%. The percentages of materials in the reaction mixtures mentioned above are based on pure materials. Acids suitable for use in this method are aliphatic dibasic carboxylic acids having about 8 to about 16 carbon atoms. These unsubstituted acids have the general formula: In the formula, R is an alkylene group having about 6 to about 14 carbon atoms. Preferred R groups have the form -( _CH2 ) _o- , where n represents a number from about 6 to about 14. And particularly preferred is dodecanedioic acid (n=10). The production reaction of diperoxy acid is as shown in the following formula. To produce the diperoxyacid, 2 moles of hydrogen peroxide appear to be required for each mole of dibasic acid used, but the excess hydrogen peroxide is 5 times the stoichiometric requirement. It is preferable to use the range up to Addition of dibasic acid to the reactor can be done in one of two different ways. The first method is to add the dibasic acid separately from the other reactants, and the second preferred method is to dissolve the dibasic acid in solution in sulfuric acid and add it through the first inlet stream. , while aqueous hydrogen peroxide is added as a second inlet stream. The dimensions of the equipment required for the method of the invention can be easily determined by a person skilled in the art once the particular desired production rate has been determined. The material of the device construction is not critical, but is preferably selected from the group consisting of glass, Teflon™ stainless steel, tantalum, aluminum, and porcelain. The process of the invention can take any form of continuously stirred reactor. Two common types of reactors of this type include the use of high-speed recirculation reactors or stirred tanks in which agitation is provided as a result of pumping action. In the former device, the reactant stream is fed to a pump rather than a mixing tank, the diperoxy acid product is recovered from the pump and flows into a heat exchanger, and a portion of the cooled product is fed to the pump. Recirculated. Each device has certain advantages, and in fact both may be used in conjunction to obtain the benefits of both. Regardless of the particular method chosen, reactor temperature is an important factor in determining the rate and characteristics of the peroxidation reaction. In the present invention, it is desirable to operate the reactor at a temperature range of about 15°C to about 45°C. Another factor that plays an important role during the reaction process is the mixing that takes place in the reactor. For maximum crystal size in stirred tank reactors, it is preferred to utilize low shear mixing, such as mixing with a slowly operating paddle type stirrer. High shear mixing, such as that provided by high speed radial turbines, results in a reduction in crystal size. Pumping equipment in the high-speed recirculation process should also be selected to minimize crystal fragmentation. The cooling required to obtain the desired temperature in either the stirred tank reactor or the recirculation process is
This can be done by any convenient method. For example, a stirred tank with a cooling coil or jacket in contact with the surface of the tank can be used. As mentioned above, different types of continuously stirred reactors may be combined. It is likewise possible for the reactor to include part of a plug flow reactor therein.
Such a combination provides improved mixing in the reactor and also helps control particle size. For example, GW Betzker and MA Larsson, “Mixing Effects in Continuous Crystallization,” Chemical, Engineering, Progress, Symposium, Series, Crystallization, Fromm, Solutions, &, Merz, No. 65.
Please refer to Vol. The entire volume is incorporated herein by reference. Once the diperoxy acid product is removed from the reactor, it must be filtered and washed.
Selection of a suitable filter depends on its crystal properties as well as the desired production rate. Since it is a part of the reactor, those skilled in the art can easily select an appropriate filter after knowing the above facts. The peroxyacids obtained using the method of the present invention can be dried using conventional drying means with the usual safety precautions encountered when handling them. Continuously stirred tank reactors such as those described above include:
Upon start-up, some diperoxy acid reaction product is added. After the reactor is in operation, a recycle stream may be used to feed a portion of the liquid reactants. In addition to obtaining crystals of larger size, the continuous process of the present invention allows for faster reaction conditions with fewer safety concerns than in batch reactors. Peroxyacid Compound-Containing Compositions The peroxyacid compounds produced by the method of the present invention can be used in a wide variety of compositions.
A preferred use is as a bleaching agent for fabrics. To ensure that compositions containing peroxy acid compounds are safe and effective, the presence of certain additives is desirable. It is well documented in the peroxyacid literature that peroxyacids are subject to a number of different safety issues as well as a number of problems. First, the latter problem is that the peroxyacid decomposes exothermically, and when the raw material is in dry granular form, the heat generated must be controlled to make the product safe. The best exotherm control agents are those that are capable of releasing water at a temperature slightly below the decomposition temperature of the peroxyacid used. US Pat. No. 3,770,816 (November 6, 1973), which is also incorporated herein by reference, describes a wide variety of hydrated materials that suitably act as exotherm control agents.
These substances include magnesium sulfate MgSO ₄ 7H ₂ O, magnesium formate dihydrate, calcium sulfate (CaSO ₄ 2H ₂ O), calcium lactate hydrate, calcium sodium sulfate (CaSO ₄
2Na ₂ SO ₄ 2H ₂ O), and compounds in the form of hydrates,
Examples are sodium aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate and aluminum sulfate. Preferred hydrates are alkali metal aluminum sulfates, particularly preferred potassium aluminum sulfates. Other preferred exotherm control agents are substances that lose water as a result of chemical decomposition, such as boric acid, malic acid, and maleic acid. The exotherm control agent may be about 100% to about 100% by weight of the peroxyacid compound.
Preferably, it is used in an amount of 200%. Another problem encountered when using peroxy acid compounds concerns maintaining good bleaching effectiveness. It has been recognized that metal ions can act as catalysts in the decomposition of peroxy acid compounds. To overcome this problem, chelating agents can be used in amounts ranging from about 0.005% to about 1.00% by weight of the composition for the purpose of immobilizing heavy metal ions. US Patent No.
Specification No. 3442937 (dated May 6, 1969) describes quinoline or its salt, alkali metal polyphosphate,
and optionally synergistic amounts of urea are disclosed. U.S. Pat. No. 2,838,459 (June 10, 1958) describes a number of polyphosphates as stabilizers for peroxide baths. These materials are also useful as stabilizers in the method of the invention. Additionally, U.S. Patent No.
No. 3,192,255 (dated June 29, 1965) discloses the use of ginardic acid for stabilizing percarboxylic acids. This material, as well as picolinic acid and dipicolinic acid, are also useful in the compositions of the invention. A preferred chelate system for the present invention is a mixture of 8-oxyquinoline and an acidic polyphosphate (preferably sodium acidic pyrophosphate). The latter may be a mixture of phosphoric acid and sodium pyrophosphate (in a ratio of about 0.5:1 to about 2:1 of the former to the latter);
The ratio of oxyquinoline is about 1:1 to about 5:1. In addition to the chelating systems described above for immobilizing heavy metals in peroxyacid compositions, coating materials can also be used to extend the shelf life of the dry particulate composition. These coating materials are generally acids, esters, ethers and hydrocarbons, and include a wide range of materials,
Examples include fatty acids, derivatives of fatty alcohols, such as esters, alcohols, derivatives of polyethylene glycols, such as esters and ethers, and hydrocarbon oils and waxes. These materials help prevent moisture from reaching the peracid compound. Secondly,
The coating material can be used to sequester the peracid compound from other agents that are present in the composition and may adversely affect the stabilization of the peracid. In practicing this method, a coating can be applied to the peracid and/or other agent. The amount of coating material used is usually approximately
2.5% to about 15%. Additional agents used to help impart good bleach performance include PH regulators, bleach activators, and minor ingredients such as colorants, dyes, and fragrances. Typical PH regulators adjust the PH of the aqueous solution of the composition.
Peroxyacid bleaches are usually used to change or maintain the pH range in which it is most effective, that is, in the range of 5 to 10. Depending on the nature of the other optional composition components, the PH modifier may be of either acid or base type. Examples of acidic PH regulators intended to compensate for the presence of highly alkaline substances include normally solid organic and inorganic acids, acidic mixtures, and acidic salts. Specific examples of these acidic PH regulators are citric acid,
These are glycolic acid, tartaric acid, gluconic acid, glutamic acid, sulfamic acid, sodium hydrogen sulfate, potassium hydrogen sulfate, ammonium hydrogen sulfate, and a mixture of citric acid and lauric acid. Citric acid is preferred due to its low toxicity and hardness sequestering ability. Optionally added alkaline PH regulators include conventional alkaline buffers. Examples of such buffers include salts such as carbonates, bicarbonates, silicates, pyrophosphates, and mixtures thereof. Particularly preferred are sodium bicarbonate and tetrasodium pyrophosphate. Such activators include materials such as aldehydes and ketones, although peroxyacid bleach activators suggested by the prior art can also be added if desired. The use of these materials as bleach activators is described in detail in US Pat. No. 3,822,114 (July 2, 1974), which is incorporated herein by reference. Preferred dry granular bleach products using the peroxy acid bleaches of the present invention are obtained by combining an active peroxy compound with potassium aluminum sulfate or boric acid with a pyrophosphate/8-oxyquinoline, and subsequently coating this mixture with balm oil. , including the step of solidifying the coated particles with a polyethylene glycol derivative. Then alkaline PH
The modifier is added to this solidified, stabilized active agent as a dry mixture. When used in combination with the active peroxy acids of the present invention to form a complete bleach product, the optional ingredients may contain from about 20 to about 99% of the total weight of the composition. Conversely, the peroxy acid compound obtained by the method of the present invention accounts for about 1% of the composition.
It accounts for 80% to 80%. The bleach compositions according to the invention, especially in dry granulation form, can be added to, or form part of, conventional textile washing detergent compositions. Accordingly, optional ingredients of the bleach compositions of the present invention may include standard detergent additives such as surfactants and builders. The optional surfactant is selected from the group consisting of organic anionic, nonionic, amphoteric and zwitterionic surfactants and mixtures thereof. Optional builder materials include any conventional organic and inorganic builder salts, including carbonates, silicates, acetates, polycarbonates, and phosphates. When the stabilized bleach compositions of the present invention are used as part of conventional fabric washing detergent compositions, the bleach compositions of the present invention typically comprise from about 1% to about 40% by weight of the conventional detergent compositions. Configure. Conversely, the bleach compositions of the present invention can optionally contain from about 60 to about 99 percent by weight of conventional surfactants and builder materials. Specific examples of suitable surfactants and builders are discussed below. Water-soluble salts of higher fatty acids, ie, "soaps", are also useful in the present invention as anionic surfactants. Surfactants of this type include the common alkali metal soaps, such as sodium, potassium, ammonium, and alkanol ammonium salts of higher fatty acids having from about 8 to about 24 carbon atoms, preferably from about 10 to about 20 carbon atoms. . Soaps can be obtained by direct saponification of fats and oils or by neutralization of free fatty acids. Particularly useful are the sodium and potassium salts of fatty acid mixtures derived from coconut oil and tallow, ie, sodium or potassium tallow and coconut oil soaps. Another class of anionic surfactants include water-soluble salts, particularly alkyl groups containing about 8 to about 22 carbon atoms in their molecular structure (the term "alkyl").
shall also include the alkyl moiety of the acyl group. ) and alkali metal, ammonium and alkanolammonium salts of organic sulfuric acid reaction products with sulfonic acid or sulfate ester groups. Specific examples of synthetic surfactants of this type that can be used in the detergent compositions of the invention include sodium and potassium alkyl sulfates, especially higher alcohols (C _8-18 carbon atoms) and sodium and potassium alkylbenzene sulfonates (of straight-chain or branched structure, the alkyl group having from about 9 to about 15 carbon atoms); , U.S. Pat. No. 2,220,009 and U.S. Pat.
No. 2477383). Other anionic surfactant compounds useful in the present invention include sodium alkyl glyceryl ether sulfonates, particularly higher alcohols or ethers derived from tallow and coconut oil, sodium coconut fatty acid monoglyceride sulfonates, and sulfuric acid. Sodium, as well as sodium or potassium salts of alkylphenol ethylene oxide sulfate (approximately 1 per molecule)
(containing from about 10 units of ethylene oxide and the alkyl group having from about 8 to about 12 carbon atoms). Additionally, other anionic surfactants useful in the present invention include those containing about 6 to 6 carbon atoms in the ester group.
Water-soluble salts of α-sulfonated fatty acid esters containing 20 2-acyloxy- esters having about 2 to 9 carbon atoms in the acyl group and about 9 to about 23 carbon atoms in the alkane moiety; Water-soluble salts of alkane-1-sulfonic acids, alkyl ethers of sulfuric acid containing about 10 to 20 carbon atoms in the alkyl and about 1 to 30 moles of ethylene oxide, about 12 to 24 carbon atoms. and β-alkyloxyalkanesulfonic acids having about 1 to 3 carbon atoms in the alkyl group and about 8 to 20 carbon atoms in the alkane moiety. . Preferred water-soluble anionic organic surfactants in the present invention include linear alkylbenzene sulfonates in which the alkyl group has about 11 to 14 carbon atoms, tallow-range alkyl sulfates, coconut oil-range alkyl glyceryl sulfonates, and alkyl glyceryl sulfonates in which the alkyl group has about 11 to 14 carbon atoms. Alkyl ether sulfates having an average degree of ethoxylation of about 14 to 18 and an average degree of ethoxylation of 1 to 6. Preferred anionic surfactants for use in the present invention include the following. namely, linear sodium _C10 - _C12 alkylbenzene sulfonate, triethanolamine _C10 - _C12 alkylbenzene sulfonate, sodium tallowalkyl sulfate, sodium glyceryl ether coconut alkyl sulfonate, and about 3 to 10 moles of tallow alcohol and ethylene oxide. It is the sodium salt of the sulfate of the condensation product. It should be noted here that all of the anionic surfactants mentioned above can be used individually or as a mixture in the present invention. Nonionic surfactants include water-soluble ethoxylated products of _C10 - _C20 aliphatic alcohols and _C6 - _C12 alkylphenols. Many nonionic surfactants are particularly suitable as foam control agents in combination with the anionic surfactants mentioned above. Semipolar surfactants useful in the present invention include:
Water-soluble amine oxides containing one alkyl moiety having about 10 to 28 carbon atoms and two moieties selected from the group consisting of hydroxyalkyl groups and alkyl groups having 1 to about 3 carbon atoms; Contains 1 alkyl moiety of about 10 to 28 and about 1 carbon number
Water-soluble phosphine oxides containing two moieties selected from a hydroxyalkyl group and an alkyl group of about 1 to 3 carbon atoms, and an alkyl moiety of about 10 to 28 carbon atoms, and an alkyl group of 1 to 3 carbon atoms. and hydroxyalkyl moieties. Amphoteric surfactants include derivatives of aliphatic or heterocyclic secondary and tertiary amines or aliphatic derivatives. The aliphatic moiety in the derivative may be straight chain or branched, in which one aliphatic substituent has about 8 to 18 carbon atoms, and at least one aliphatic substituent has an anionic water-soluble group. Zwitterionic surfactants include derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds. The aliphatic moiety in the compound may be straight chain or branched, and one of the aliphatic substituents contains about 8 to 18 carbon atoms, and the other carries an anionic water-soluble group. It contains. The granular compositions according to the invention may also contain detergent builders commonly used in cleaning compositions. Builders useful in the present invention include any conventional inorganic and organic water-soluble builder salts, as well as various water-insoluble, so-called "seeded" builders. Inorganic detergent builders useful in the present invention include:
For example, water-soluble salts such as phosphates, pyrophosphates, orthophosphates, polyphosphates, phosphonates, carbonates, bicarbonates, borates, and silicates are included. Examples of inorganic phosphate builders include sodium and potassium triphosphates, phosphates, and hexametaphosphates. Specific examples of polyphosphonates include, for example, the sodium and potassium salts of ethylenediphosphonic acid, the sodium and potassium salts of ethane-1-oxy-1,1-diphosphonic acid, and the sodium and potassium salts of ethane-1,1,2-triphosphonic acid. . Examples of these and other phosphorus, builder compounds are described in U.S. Pat.
3159581, 3213030, 3422021, 3422137, 3400176, and
No. 3400148 and is disclosed in each specification. Sodium triphosphate is a particularly preferred water-soluble inorganic builder in the present invention. Non-phosphorus-containing sequestrants can also be used as detergent builders in the present invention. Specific examples of non-phosphorous inorganic builder components include water-soluble inorganic carbonates,
There are bicarbonates, borates, and silicates. Particularly useful in the present invention are carbonates, bicarbonates, borates, and silicates of alkali metals, such as sodium and potassium. Water-soluble organic builders are also useful in the present invention, such as alkali metals, ammonium,
and substituted ammonium polyacetates, carboxylates, polycarboxylates, succinates, and polyoxysulfonates are useful builders in the compositions and methods of this invention. Specific examples of builder salts of polyacetates and polycarboxylate salts include sodium, potassium, lithium, ammonium, and substituted ammonium of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acid, and citric acid. Salts are included. In the present invention, highly preferred non-phosphorous builder substances (both organic and inorganic) include sodium carbonate, sodium bicarbonate, sodium silicate, sodium citrate, sodium oxydisuccinate, sodium melitate, sodium nitrilotriacetate, and ethylenediamine. Sodium tetraacetate, as well as mixtures thereof. Other types of detergent builder materials useful in the compositions and methods of the present invention include water-soluble materials capable of producing water-insoluble reaction products with water-hardness cations in combination with crystallization seeds. (The seed crystals provide a growth site for the reaction products). Specific examples of substances that can produce water-insoluble reaction products include carbonates, bicarbonates, sesquicarbonates,
Water-soluble salts include silicates, aluminates, and oxalates. The alkali metal, especially sodium, salts of said materials are preferred for reasons of convenience and economy. Other types of builders useful in the present invention are capable of reducing the hardness content of the wash liquor, for example by ion exchange techniques. A variety of substantially water-soluble substances are included. Examples of such builder substances include U.S. Pat. No. 3,424,545 (January 1969).
28) (incorporated by reference). Aluminosilicate complexes, i.e. zeolite-type materials, soften water, i.e. Ca ⁺⁺
It is a useful presoak/wash additive in the present invention in that it removes hardness. Both natural and synthetic "zeolites", especially zeolite A
and hydrated zeolite A materials are useful for this builder/softener purpose. Zeolite materials and methods for their preparation are described in US Pat. No. 2,882,243, dated April 14, 1959, which is incorporated by reference. Composition Preparation When preparing the bleach composition according to the present invention in the form of dry granules, the components are mixed, agglomerated, compacted,
Alternatively, it can be carried out by any conventional method such as granulation. In one method of preparing such compositions, a peroxyacid-water mixture containing about 50% to about 80% water by weight is combined with any ingredients to be used in the granular bleach in appropriate proportions. Combine. The combination of such components is then thoroughly mixed and subsequently passed through an extruder. Next, the noodle-like extruded product is fed to a spheronizer (known under the trade name "Marmerizer") to form approximately spherical particles from the peroxy acid-containing noodle-like product. Next, the granular bleach is dried to an appropriate moisture content. Immediately after leaving the spheronizer, the granules are sieved to achieve uniform particle size. The granular bleach thus prepared can then be mixed with granules of any other bleach or detergent composition materials. The actual particle size of either the bleach-containing granules or the optional granules of additional material is not limiting. However, certain particle size limitations are highly desirable if commercially acceptable flow performance is to be achieved with the composition. Generally, all particulates of the compositions of the present invention preferably range in size from about 100 microns to 3000 microns, more preferably from about 100 microns to 1300 microns. Furthermore, flowability is enhanced if the particles of the present invention are of approximately the same size. Therefore, the ratio of the average particle size of the bleach-containing granules to the optional granules of other materials is preferably in the range of 0.5:1 to 2.0:1. The bleach composition of the present invention is dissolved in water and used in an amount sufficient to provide about 1.0 ppm to 100 ppm of available oxygen in solution. Typically, this amount equates to about 0.01 to 0.2% by weight of the composition in solution. The fabric to be bleached is then contacted with the aqueous bleaching solution described above. The method of the invention is illustrated in the following example. Example 1 The advantages of the continuous method of the invention over the batch method are demonstrated in the experiments described below. A Diperoxide dodecanedioic acid is produced using a batch reactor equipped with a stirrer. In the process, (a) 50 g of dodecanedioic acid is dissolved in 97% sulfuric acid.
The solution is cooled to 10° C. while dissolving in 213.6 g. (b) 116.7 g of 67.8% hydrogen peroxide, water
57.5 g and 213.3 g of 97% sulfuric acid at a temperature of 27
A peroxide mixture is prepared by mixing together while keeping the temperature below 0C. (c) Cool mixture (b) to 6°C. (d) Mix solution (a) and mixture (b) quickly and maintain at a temperature of 35°C for 1 hour. The produced diperoxide dodecanedioic acid precipitates. The precipitate is washed with water and collected by filtration. The collected crystals are evaluated for particle size, fraction, and available oxygen. B. A second batch of seeded diperoxide dodecanedioic acid is prepared using a batch reactor equipped with an agitator. In the process, (a) and (b) are repeated as described above. Peroxide mixture (b)
200 g of the reaction product from A was added at a temperature of about 9°C.
Add so that the temperature of the final mixture is 30°C. To this mixture is added the dodecanedioic acid/sulfuric acid solution as described in (a) above, and the temperature of the reaction mixture is maintained at about 35° C. for 1 hour. The resulting diperoxyacid is filtered, washed with water, and analyzed for particle size, excess, and available oxygen. C The reaction in a continuous stirred tank is carried out by continuously feeding the following two types of streams to the reactor, similar to the batch reactor. (a) A solution containing 10.4% dodecanedioic acid and 89.6% (97%) sulfuric acid, flow rate 16.3 g/min, and (b) a mixture containing 45.2% hydrogen peroxide and 54.8% water, flow rate 5.94 g/min. / minute flow. The reactor temperature is increased from 20°C to about 35°C for the first 90 minutes and held at about 35°C for the next 210 minutes. The diperoxy acid product is continuously recovered from the reaction vessel, filtered, washed, and analyzed. Product recovery is such that the average residence time in the reactor is approximately 56 minutes. At the start of the reaction, the reaction vessel is filled with the reaction product produced using a batch reactor as in A above. The increase in crystal size in a continuous reactor is shown in the table below.

【table】

[Table] Luther cake thickness)
*Concentration of the liquid phase (excluding dodecanedioic acid) entering the reactor prior to the reaction.
It will be appreciated that the continuous process yields larger and more easily passable crystals than in either conventional batch reactions or batch reactions seeded with diperoxy acids. Similar results to those mentioned above are obtained when the dibasic acid is
Other acids selected from the group consisting of acids having the structure below are also obtained. (In the formula, n is a number from about 6 to about 14.) (n=10 for dodecanedioic acid)

Claims (1)

[Claims] 1. A method characterized by comprising the following steps:
A continuous method for producing diperoxy acid represented by the following formula. (In the formula, n is a number from about 6 to about 14.) (a) A step of continuously adding the following substances to a stirred reactor at a temperature of about 15°C to 45°C. (1) hydrogen peroxide, (2) water, (3) sulfuric acid, and (4) dibasic acid represented by the following formula. (b) Continuously recovering from the reactor the diperoxy acid product formed as a result of the oxidation of the dibasic acid. (c) Passing the diperoxy acid product. (d) washing the diperoxy acid product with water and drying it. However, sulfuric acid, hydrogen peroxide,
and the water inflow rate is sufficient to maintain liquid concentrations in the reactor of about 60% to about 80% sulfuric acid, about 0.5% to about 15% hydrogen peroxide, and 5% to 39.5% water. . 2 The inflow rates of sulfuric acid, hydrogen peroxide, and water are
The claimed invention is sufficient to maintain a liquid concentration of about 60% to about 80% sulfuric acid, about 2% to about 15% hydrogen peroxide, and about 5% to 38% water in the reactor. The method described in Scope 1. 3. The method of claim 2, wherein the aliphatic dibasic acid is dissolved in the sulfuric acid prior to addition to the reactor. 4. The method according to claim 3, wherein the aliphatic dibasic acid is dodecanedioic acid. 5. The method of claim 2, wherein the reactor is a fast recirculation reactor. 6. The method of claim 2, wherein the reactor is a mixed reactor having both a stirred tank section and a high speed recirculation section. 7. The method of claim 2, wherein the reactor is a mixed reactor having both a stirred tank section and a plug flow section. 8. Claim 2, wherein the reactor is a mixed reactor with a fast recirculation section and a plug flow section.
The method described in section. 9. The method of claim 2, wherein the reactor is a mixed reactor having a stirred tank section, a fast recirculation section, and a plug flow section.