FI106958B - Method for Stabilizing Peroxy Compounds - Google Patents

Description

106958 METHOD FOR STABILIZING PEROXY COMPOUNDS Background of the Invention

The invention relates to the stabilization of peroxy compounds and relates in particular to the prevention of degradation by metal ions. The invention can be used, for example, in various cleaning and bleaching methods and agents in which peroxy compounds are used.

Peroxy compounds, such as hydrogen peroxide, hydrogen peroxide derivatives or peroxy acids, are potent oxidizing agents. They can be used for various cleaning or bleaching purposes. When such compounds are used, they may become on-10 gecq due to their lack of stability. In many cases, harmful chemicals that degrade these compounds enter the process through chemicals, the material being treated, or process waters. These contaminants can be either organic or inorganic. The most harmful are heavy metals such as manganese, iron and copper, which catalyze the decomposition of peroxy compounds. For example, chromium also adversely affects. Heavy metals can not only degrade the peroxy compounds, thereby correspondingly increasing their consumption, but also otherwise damage the material being treated.

«

The adverse effects of metal ions can be reduced by binding them with a complexing agent. In particular, chelating agents such as polyaminopolycarboxylic acids are used as complexing agents. These include, in particular, ethyl 20 -enediaminetetraacetic acid (EDTA) and its salts and diethylenetriaminepentaacetic acid (DTPA) and its salts. Also very effective are some phosphonic acids, * * of which are commonly used phosphonic acids corresponding to EDTA and DTPA, ethylenediaminetetra (methylene phosphonic acid) (EDTMPA) and its salts, and diethylene triamine-penta (methylene phosphonic acid) (its DTPMPA).

In laundry detergents, perborates, sodium carbonate peroxyhydrate or similar solid peroxide sources are often used as bleaching agents in combination with a suitable activator. The activator used is, for example, tetraacetylethylenediamine (TAED). Hydrogen peroxide and peroxyacids are formed in the washing solution. Detergents are commonly used to form complexing agents, such as EDTA or phosphonates, to bind harmful heavy metals and calcium, to stabilize the washing solution, and to provide other washing enhancing effects. Perborates and sodium carbonate peroxyhydrate with or without activator have also been used in dishwashing detergents.

2 106958

Peroxy compounds are also commonly used to treat wood pulp, in particular as bleaching chemicals. In these processes, too, heavy metals in particular are harmful when decomposing peroxy compounds, and efforts must be made to prevent heavy metals in general. For example, patent application FI-A-942968 discloses transition-5 metal-activated bleaching of wood pulp with peroxy compounds under acidic conditions. The process uses DTPA, EDTA or DTMPA to chelate heavy metals.

However, chelates can also catalyze the degradation of peroxy compounds. For example, in Z. Yuan, et al., "The Role of Transition Metal ions in Peracetic Acid Bleaching of Chemical Pulps", Pulp & Paper Canada 98:11 (1997), p. 24-29, it has been found that the manganese complex of DTPA catalyzes the decomposition of both peracetic acid and hydrogen peroxide. The corresponding Μη complex of the phosphonate, DTPMPA, also catalyzes the decomposition of peracetic acid.

The most commonly used complexing agents today are either completely biodegradable, such as EDTA and the phosphonates mentioned, or poorly biodegradable, such as DTPA. Another environmental issue is the issue. the nitrogen and phosphorus content of the substances. It is generally assumed that in the presence of transition metal (heavy metal) ions, a chelating agent having at least one nitrogen atom is required. Nitrogen-free complexing agents, at least when used alone, have so far failed to achieve, for example, a good bleaching effect on wood pulp.

Description of the Invention

A stabilization method according to claim 1 has now been invented. Certain preferred embodiments of the invention are set forth in the other claims.

According to the invention, a compound of the following formula is used to stabilize the peroxy compounds

B

* 'AOOC — C — O — CH —COOA

I I

R is CH2-COOA

wherein R = H or (CH 2) n COOH, where n is 1-3 and A = H, an alkali metal ion such as Na or K, or the equivalent of an alkaline earth metal ion such as Mg or Ca.

3, 106958

Particularly, the compounds of the formula include carboxymethyloxysuccinic acid (CMOS), wherein R is H, and oxysuccinic acid (ODS), where R is CH 2 COOH, and salts thereof.

Stabilization can be accomplished by adding the stabilizer of the invention to the peroxy compound or to the mixture containing it or to the substance to be treated. The stabilizer may also be added to the mixture prior to the peroxy compound.

A suitable amount of stabilizer may be, for example, 0.001 to 50%, such as 0.01 to 5%, by weight of the peroxy compound.

The advantage of the invention is above all that the stabilization can be carried out with a nitrogen-free compound. The stabilizing compound also does not contain phosphorus. The process is thus very advantageous from an environmental point of view. However, the stabilization result is very good.

The peroxy compound may be, for example, hydrogen peroxide, peroxy acid such as peracetic acid, or hydrogen peroxide such as sodium borate or sodium peroxide acid produced by hydrogen peroxide or a derivative of hydrogen peroxide such as sodium perborate or sodium carbonate peroxyhydrate.

·; The stabilization of the invention can be utilized, for example, in various purification or bleaching processes or in the preparation and storage of peroxy compounds.

When the stabilizing compound is added to the process, it can be added simultaneously or nearly simultaneously with the peroxy compound.

•

Please blame why. substances work, unknown. In any case, it should be the case that the transition metal complexes of the substances of the invention do not catalyze the decomposition of the peroxy compounds, despite being weaker complexing agents for heavy metals than (poly) aminopolycarboxylates such as EDTA and DTP A and similar phosphonates such as EDMPA. On the other hand, they may potentially activate radicals formed from peroxy compounds.

For example, CMOS can be prepared by the maleic-glycolic acid coupling reaction. The coupling reaction takes place under alkaline conditions and may use, for example, lanthanides as a catalyst. ODS can be prepared by reaction of malic acid with maleic acid. Other compounds of the formula may also be prepared in a similar manner starting from maleic acid or its derivatives. CMOS and ODS are also in the EINECS registry, and the preparation of the former is described, for example, in 4,106,958 by J. van Westrenen et al., Inorganica Chimica Acta 1991, p. 233-243. The product is readily biodegradable.

One aspect of the invention is the use of various washing methods and detergent compositions employing peroxy compounds. The stabilizing agents of the invention may be added to the detergent mixture or separately during the washing process itself.

When peroxy compounds such as perborates or sodium carbonate peroxyhydrate are used in detergents, for example with TAED, peracetic acid is formed in the washing solution in addition to hydrogen peroxide. It has now surprisingly been found that with the stabilizing agents of the invention higher concentrations of peracetic acid 10 can be achieved and solutions more stable with respect to the peroxy compound are obtained than with conventional chelating agents such as EDTA.

Em. the stabilizers can also advantageously be used in other detergents in which the activator is not TAED but another substance which also forms peracetic acid or another peroxyacid. An example of the latter is iso-nonyl-15-benzenesulfonate (iso-NOBS), which is used as a commercial activator.

When both peroxy acid and hydrogen peroxide are present in the washing solutions and the portion of the hydrogen peroxide which has not been converted to peroxy acid remains stable over time, it is clear that these stabilizers can also be used in detergents containing hydrogen peroxide. The tendency for hydrogen peroxide to decompose increases with increasing pH. Therefore, the stability-enhancing effect of hydrogen peroxide is best manifested above pH 7. When used with current laundry detergent powders, these will usually result in a pH close to 11.5, although today there is a trend toward lower washing pHs.

The stabilizing agents of the invention can also advantageously be used in dishwasher detergents using peroxy compounds such as perborates and sodium carbonate-Tiperoxyhydrates. In addition to the calcium binding capacity, this provides improved stability of the bleaching agent. The stabilizers of the invention may also be included as a stabilizer in perborates and sodium carbonate peroxyhydrate. The latter product is most often coated to improve shelf life, and the stabilizers of the invention may be incorporated into the product and / or coating itself.

Another use of the invention is the treatment of wood pulp with a peroxy compound. Heavy metals which impede the bleaching and delignification of pulps can be made by the use of a processor

Harmless by separate treatment or by adding a stabilizer to the bleaching solution itself.

In the perox bleaching of chemical pulps, the binding of all metals is generally not possible under alkaline conditions, since, for example, iron is precipitated as hydroxy-5, oxides and oxide hydroxides, which strongly catalyze the decomposition of the peroxy compounds. As a result, stabilization prior to peroxy bleaching, for example hydrogen peroxide bleaching, is carried out under acidic conditions. In this case, especially the removal of manganese is important. Manganese can best be removed at pH 4.5-6.5.

In modern chemical pulp bleaching processes, bleaching is preceded by oxygen 10 delignification. In this process, magnesium ions have been added to the pulp, which retention in the pulp is important when bleaching with peroxy compounds such as hydrogen peroxide. The best Mg / Mn ratio is achieved at pH 4.5-5. Therefore, stabilization is best performed at well below pH 6, for example near pH 5.5, for example at pH 5.3.

The upstream end of the bleaching sequence is to remove the lignin and only the downstream end of the bleaching actually performs the bleaching. Today, as lignin is increasingly removed in cooking and subsequent oxygen delignification, the difference in concepts has blurred. However, if the lignin-depicting kappa values after oxygen delignification are greater than 10, or only as high as 10 to 6, the first bleaching step is in fact merely a delignification step. Delignification can be carried out quite selectively with peroxy acids, for example peracetic acid, whereby delignification is carried out near pH 5. Any delignification or bleaching with peroxy compounds can be accompanied by a stabilization according to the invention to eliminate the adverse effects of heavy metals. In this case, it is advantageous that the stabilizer can be added, for example, directly to the step, whereby simpler device solutions can be achieved and also the pulp throughput time in the bleaching process can be accelerated. In this way, the economic efficiency of the process can be further improved.

. If peroxy acids are used downstream of the bleaching sequence, the following steps are usually carried out at a higher pH than the delignification step, because the bleaching properties of the peroxy acids, for example peracetic acids, are better at an elevated pH, for example at pH 7-9.

The stabilizers of the invention can also be used in bleaching mechanical pulps. For example, the peracetic acid-hydrogen peroxide sequence (PAA-P) may be used in the bleaching, whereby the bleaching is carried out in the PAA step near a neutral pH of 6,106,958. The use of peracetic acid has the advantage that the sodium silicate normally required for the bleaching of mechanical pulp does not need to be used. The agents of the invention can be used in all such sequences involving the use of peroxy compounds, and most preferably, without the need for a separate stabilization step, but with the addition of a stabilizer during bleaching.

Another object of the invention is the stabilization of peroxy compounds or mixtures containing them during their preparation or storage.

The invention is illustrated by the following examples, which, however, do not limit the scope of the invention.

EXAMPLE 1 To test the stability of peracetic acid (PAA) generated from TAED, experiments were performed without stabilizers and with ODS. To determine the effect of the metals, manganese and iron ions were added to the solution at a concentration of 0.2 mg / l each. Because pH significantly affects the results, the experiment was also carried out at slightly higher pH. In the tests, a solution of 1 g of Na 2 CO 3 / l, metals and a stabilizer in acid form of 140 mg / l (calculated as 100%) was used. The solution was heated to 50 ° C and hydrogen peroxide and pure, uncoated TAED were added to a concentration of 3 and 2 g / l. TAED was thus less than the hydrogen peroxide equivalent ratio in the assays, given that TAED is capable of binding 20 to 2 molecules of hydrogen peroxide. The amount of hydrogen peroxide and peracetic acid was determined by standard methods; first on ice with a solution of cerium sulfate hydrogen peroside and then iodometrically with peracetic acid.

1 · · 7 106958

table 1

Stabilizer / Time pH H202 PAA H202% Initial PAA% Target_min_g / 1 g / L of Theoretical No 0 7.8 5 7.1 2.335 0.296 82.2 22.2 10 6.8 2.138 0.272 75.4 20.4 15 6 , 6 2,092 0.257 73.6 19.2 20 6.5 2.046 0.220 71.5 16.5 25 6.4 1.994 0.212 69.6 15.8 __30 6.3 1.939 0.200 67.6__15.0 yes 0 7.8 5 7,0 2,598 0,604 95,6 45,3 10 6,6 2,414 0,587 89,2 44,0 15 6,5 2,329 0,554 85,9 41,6 20 6,4 2,269 0,538 83.7 40,4 25 6 , 2 2,252 0,539 83,1 40,4 __30 6,2 2,186 0,440 79,4__33,0 yes 0 8,0 5 7,5 2,309 0,664 86.9 49.8 10 7.2 2,176 0.921 86.2 69.1 15 7.1 2,069 0.952 83.2 71.4 20 7.1 2.094 1.076 85.9 80.7 25 7.0 1.981 0.958 80.3 71.9 _ 30 7.0 1.981 0.936 80.0_ 70.2

Tests with ODS were performed on solutions of different concentrations with a total acid content of 5. This is due to differences in pH in the assays.

First of all, it can be seen from the table that peracetic acid is more formed when ODS is used. Secondly, it can be seen that raising the pH increases the amount of peracetic acid produced. It can also be observed that the use of ODS improves the total amount of peroxy compounds (calculated as hydrogen peroxide in the table).

Example 2

Next, a new experiment was performed which mimic the washing conditions at high pH, about 10.5. The water used was cured with CaCl2 to a hardness of 12 ° dH. 106958 g of water were additionally added with 0.0045 mg / l of manganese, 0.08 mg / l of iron and 0.002 g / l of copper to meet the conditions when using tap water for washing. The experiment was carried out in the same manner as the previous experiment, except that the amount of hydrogen peroxide was 0.66 g / l and the amount of TAED was 0.6 g / l. Additionally, 2 g / L sodium carbonate was added to the solution. The amount of stabilizer-5 in all experiments was 140 mg / L. The experiment was performed at 50 ° C.

Table 2

Stabilizer / Time pH H202 PAA H202% Initial PAA% Theoretical Target_min_g / 1 g / L of Derivative_ No 0 10.7 5 10.5 0.343 0.212 66.4 53.1 10 10.5 0.303 0.122 54.2 30.4 __15 10.5 0.253 0.0578__42.2__14 ^ _ EDTA 0 10.7 5 10.5 0.349 0.182 65.2 45.6 10 10.4 0.239 0.106 43.5 26.6 15 10.4 0.234 0.0732 40 , 4 18.3 CMOS 0 10.7 5 10.5 0.380 0.227 73.0 56.9 10 10.4 0.295 0.165 55.9 41.3 _ 15 10.5 0.260 0.0816 44.9_ 20.4_ •

From the results, it can be seen that the peroxy compounds in this system are most unstable than under the conditions of the previous experiment. However, CMOS is a better stabilizer than EDTA. However, comparing the tests in Tables 1 and 2 without the use of stabilizers, it can be seen that at higher pH more peracetic acid is produced but that the system is much more unstable with respect to the peracids. Part of the reason is at least that hydrogen peroxide decomposes faster at higher pH. However, the results show that the use of CMOS improves the yield of peracetic acid and does not impair the stability of the bleaching solution, but on the contrary slightly improves the overall result.

Example 3

To determine how the quality of the metal ions and, on the other hand, the pH between the pHs used in Examples 1 and 2, influenced the results, experiments were conducted on different metal ion systems and at different pHs. Experiments were performed using ODS as a stabilizer as in Experiment (Vol. I). The second Saija used hardened water and metal ion amounts as in Example 2 (Series II). The pH adjustment was done by adding the same amount of sodium carbonate in Series I experiments and the same amount in Series II experiments. 5 (Note: not the same in Saqs I and Π).

Table 3

Stabilizer / Time pH H2O2 PAA H202% Initial PAA% Target_min_g / 1 g / l of Derivative No, Series I 0 9.8 5 8.0 2,128 0.200 73.9 15.0 __10 7.5 1.990 0.342 71.4__25.6 ODS, Saija I 0 9.7 5 8.1 2,374 0.452 85.9 33.9 __10 7.5 2.105 0.649 79.8__48.7 no, series II 0 9.7 5 7.5 2.206 0.191 76.4 14, 3 __10 7.2 2,112 0.207 73.5__15.6 ODS, II II 9.1 9.1 7.5 7.56969 0.312 87.0 23.4 __10 7.2 2.291 0.409 82.4__30.7 CMOS, II II 9, 9 10 7.6 2.214 0.253 77.6 19.0 _ 15 7.3 2.137 0.282 75.4 21.2

It can be seen that, especially with a system that simulates laundry water 10 containing small amounts of iron, manganese and copper, a very clear improvement is obtained when using ODS as a stabilizer and good results also with CMOS.

«• Example 4

The laundry pH is generally higher than that shown in Table 3. For this reason, experiments were performed according to Series II as in Example 3 but the amount of sodium carbonate was increased.

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Table 4

Stabilizer / time pH H2O2 PAA H2O2% initial PAA% of target_min_g / 1_g / 1_ theoretical no, series II 0 10.5 5 10.2 1.783 0.177 62.1 13.3 __10 10.2 1.222 0.0562 41.6__4, 2 ODS, Saija II 0 10.5 5 10.2 1.976 0.440 72.4 33.0 __10 10.1 1.560 0.151__H3__11.3 CMOS, serial 0 10.4 5 10.2 2.131 0.271 75.1 20.4 _ 10 10.2 1.970 0.319 70.4 23.9

Since the conditions set forth in the above experiments (Examples 1-4) are similar to those resulting from the use of detergent compositions containing NKPH and activator, it is clear that these chelating agents can be used in or with NKPH.

Example 5

To determine the potency of the stabilizers when using NKPH, the stabilizers were tested in the same manner as in Experiment 2, but using 2.21 g of crystalline NKPH and sodium sulfate-coated NKPH instead of hydrogen peroxide. Sodium carbonate was not added in the experiments and the amount of stabilizers was 200 mg / L. The initial active oxygen content of these NKPH products was 14.4% and 13.7%. The theoretical amount of hydrogen peroxide thus formed in the solution would be 0.68 and 0.64 g / l.

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Table 5 NKPH / stabilization time pH H 2 O 2 PAA H 2 O 2% initial PAA. % theoretical / target_min_g / 1 g / 1_from_the_

Crystalline / Not 0 10.6 5 10.4 0.510 0.160 85.9 58.5 __15 10.3 0.399 0.0550 62.5__20.1

Crystalline / ODS 0 10.6 5 10.5 0.557 0.202 95.6 73.8 __15 10.4 0.456 0.0874 73.2__32.0

Coated / Not 0 10.7 5 10.5 0.350 0.199 68.3 73.1 __15 10.3 0.312 0.0561 52.4__20.5

Coated / ODS 0 10.6 5 10.3 0.419 0.221 80.5 80.8 _ 15 10.3 0.325 0.0850 56.5 31.1

It can be seen that both the amount of peracetic acid formed and the total amount of peroxy compound 5, calculated as hydrogen peroxide, was higher when ODS was used than when it was not.

Stabilizers such as ODS and CMOS may also advantageously be included in NKPH and / or its coating, whereby the stabilizer need not be used separately.

* 10 Example 6

In the past, sodium sulfate has been shown to have a good effect on NKPH stabilization if NKPH is tested in combination with a detergent zeolite under warm and humid conditions that attempt to simulate detergent NKPH degradation in contact with warm and humid air. In such assays, NKPH, which is very stable in itself, degrades very rapidly, as shown e.g. Applicant Patent Application Publication WO 98/32831 (NAS-PVP Coating).

The following experiment tested the effect of CMOS and ODS in such a simulated test.

106958 The coating of NKPH was carried out on a coating machine was Aeromatic Strea 1. 400 g of unsaturated NKPH granules made with a fluidized bed granulator were used as the raw material. The NKPH used as starting material had an active oxygen content of 14.9%. Sodium sulfate was dissolved in water to form a nearly saturated solution. After all the sodium 5 sulfate had dissolved, a stabilizer, CMOS or ODS was added to make it 300 ppm (calculated as acid) of the sodium sulfate (NAS) and the temperature was raised to 60 ° C. The solution was then pumped at this temperature into the coating apparatus. The fluidization temperature was about 50-55 ° C during the plating, which was continued until the plating amount was 10% by weight. After plating, fluidization was continued until the moisture content was less than 0.5%. This requires max. 30 minutes. The samples had an active oxygen content of 13.6%.

Stability tests were performed by mixing the first samples with zeolite 4A in a 50:50 weight ratio. Approx. 5 g. sample was placed in an open flat bottomed flat container. The vessel was placed in an oven having a temperature of 30 ° C and a relative humidity of 70%. The samples were assayed for the concentration of active oxygen by titration of hydrogen peroxide with potassium permanganate solution. The control sample was previously coated NKPH in the same manner, with no CMOS or ODS coating.

Table 6 20 ___ Sample Decomposition% Decomposition% __1 week_2 weeks_i NKPH / NAS 9.5 13.3 NKPH / NAS / CMOS 6.4 15.3 NKPH / NAS / ODS _M_ 15.2

It can be seen that stabilizers do not degrade the '' external '' stability achieved by sodium sulphate alone.

• Example 7 Another method of measuring stability is the so-called. TAM (thermal activity measurement), which measures the resulting heat generation under controlled conditions. Such a measuring method is disclosed in WO 95/15292, p. 16. An isothermal microcalorimeter is used in the experiments. The test results indicate whether the product can be stored and transported as a sweat. It has often been found in many experiments that, even if the external stability is good, this result obtained with TAM measurements is poor. The cause of this separation has not been established. It has been speculated that the result obtained by TAM measurements describes the internal stability of NKPH, whereas experiments conducted in mixtures of NKPH and zeolite in the oven more closely describe the external stability of the detergent under open storage.

The following experiment was conducted to determine the effect of CMOS and ODS on TAM measurement results when added to NAS coating solutions.

Experiments were performed with a Thermal Activity Monitor type 2277 (Thermometric AB, Järfalla, Sweden) equipped with four calorimeter units and a double-bulb-10 system. The sample was weighed into an ampoule to be examined and sealed. Measurements were made at 40 ° C, producing humidity equivalent to the critical moisture in the ampoule. Samples containing CMOS and ODS were the same as in the previous example.

Table 7 15 _ · __

Time / Sample / INKPH / NAS / CMOS INKPH / NAS / ODS

heat evolution in mW / kg ___ 3 h 1.62 3.37 6 h 2.32 4.93 9 h 2.57 5.48 12 h 2.66 5.89 15 h 2.72 6.28 18 h 2.72 6 , 49 21h 2.63 6.59 24h_ 2 ^ 82_ 6.78 In practice, it has been found that the heat evolution should be less than 10 mW / kg in a long-term test, 24 hours, for NKPH to be stored and transported in bulk. From the results it can be seen that especially CMOS, but also ODS, produce very small heat developments. The heat generated by CMOS is exceptionally low. NKPHs coated with conventional NAS coating usually produce a heat development of between 10 and 15 mW / kg.

The above test results show that the use of CMOS or ODS achieves both good external and internal stability.

ODS and CMOS thus contribute to the formation of peracetic acid and the stability of peroxy compounds in solutions. From the above experiments, it appears that it is advantageous to add CMOS or ODS already to the coating, whereby no separate addition to the bleach solution or detergent is required. In this case, the detergent manufacturer does not have to mix e.g. 5 CMOS or ODS in the preparation of the detergent, but the manufacturer can purchase a stabilized NKPH that will withstand transport and provide the same stabilizing properties as when added. substances in the manufacture of detergent or in the washing process itself. However, the amounts of material added must be sufficient to achieve optimal generation and / or stabilization of the peroxy compounds.

CMOS and ODS can also be added during the NKPH manufacturing process itself and / or during the coating of the NKPH.

Since in the detergent application of hydrogen peroxide the dissociation constant, pKA, is 11.5 and peracetic acid is 8.2, it is probably the optimum pH at some of these pH values for the stability of the bleaching solution and the formation of peracetic acid. 15 In laundry, the result of bleaching depends on many factors, such as the quality of stains, the temperature of the melt and the time. This makes it difficult to determine the optimal range. However, since the stabilizers of the invention, when used, operate throughout the wash range from pH 7 to pH 11, it can be seen in the light of the results that they provide benefits in various washing solutions.

The chelating agents of the invention may also be used in solid detergents containing perborate or NKPH as a bleaching agent. Since the latter bleaching agent is usually coated, the chelating agent may be incorporated either into the NKPH itself or in and into the coating thereof.

The stabilizers of the invention may also be advantageously used in cleaning and disinfecting agents containing peracetic acid and / or hydrogen peroxide to improve the stability of solutions.

Example 8

Oxygen delignified in softwood cooked in a SuperbatchR digester with a mass kappa of 3.6, a viscosity of 718 dm 3 / kg and a brightness of 64.4% ISO deligni-30 were bleached and bleached with the sequence PAA / Q-P where PAA / Q means the fact that the chelating agent was added during the peracetic acid bleaching and where the dash indicates that there was conventional washing between the steps. The conditions for the peracetic acid phase in all experiments were as follows: time 120 minutes, temperature 70 ° C, consistency 10% and initial pH 5.5 and dosage of peracetic acid (distilled PAA) 12 kg / ts (100% by weight). Corresponding figures in the peroxide step were: 180 minutes, 90 ° C, 10% and 10.4, and a dose of 20 kg / ts of hydrogen peroxide and 10 kg of NaOH / ts. Other reaction conditions and results are shown in the table below.

Table 8 5 __

Step / Item PAA / Q PAA / Q PAA / Q PAA / Q PAA / Q

the chelating agent is not DTPA EDTA CMOS ODS

dosage, kg / ts 2 2 2 2 residual PAA kg / ts 3.7 0.6 1.0 3.7 3.4 kappa 2.4 3.1 2.8 2.5 3.0 Δ-kappa 1, 2 0.5 0.8 1.1 0.6 PAA. kg / kappa 6.9 22.8 13.8 7.5 14.3 viscosity dm3 / kg 707 681 680 707 718 A- visisk / A-kappa 9.2 74.0 47.5 10.0 0 lightness ,% ISO 74.7 72.1 73.0 74.7 74.0

__I 1 1 I

Step / Item P P P P P

residual H2O2 kg / ts 5.0 9.1 10.9 14.6 14.8 H2O2 - consumption kg / ts 15.0 10.9 9.1 5.4 5.2 kappa 1.7 1.9 1, 8 1.5 1.4 A-kappa * 1.9 1.7 1.8 2.1 2.2 viscosity, dm3 / kg 517 570 582 654 637 A-visk / A-cap * 118.2 77, 9 75.6 42.7 36.8 Brightness,% ISO 86.8 84.6 84.8 85.9 85.4 Brightness Increase, 22.4 20.2 20.4 21.5 21.0% ISO * * increase in lightness,% ISO / kg 1.49 1.85 2.24 3.98 4.04 '1η202__ * Total Kappa decrease in both PAA and P ** total increase in brightness in both PAA and P

From the results it can be seen that in the absence of a stabilizing agent, PAA is achieved with a good lightness, but viscosity is far too low for the mass to read. The reason for the decrease in viscosity is the lack of a stabilizer. On the other hand, transition metals are well complexed by EDTA and DTPA, but since the Μη complexes of these substances degrade peracetic acid, their use is even harmful. When using CMOS, good lightness and the highest viscosity of 5 are achieved. In addition, the consumption of peracetic acid and hydrogen peroxide is most advantageous.

The stabilizers of the invention can also be used after the PAA / Q step in a separate stabilization step to enhance peroxide bleaching. Such separate treatment can also be replaced by the use of the stabilizers of the invention directly in the peroxide step.

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Claims (10)

A process for stabilizing peroxy compounds, wherein the peroxy compound is a hydrogen peroxide, a peroxy acid or a peroxy acid produced with an activator of hydrogen peroxide or a derivative of hydrogen peroxide, characterized in that a compound of formula 1 is used for the stabilization H AOOC-C-O -CH-COOA IIR CH 2 -COOA (1) in which R = H or (CH 2) nCOOA, wherein n is 1-3 and A = H, an alkali metal ion such as an Na or K ion, or an equivalent. , of an alkaline earth ion such as an Mg or Ca ion. The method of claim 1, wherein carboxymethyloxy tartaric acid or oxide tartaric acid or their site is used for the stabilization. 20 The method of claim 1 or 2, wherein the amount of stabilizing compound is 0.001-50%, as well as 0.01-5% of the weight of the peroxy compound. Process according to any of claims 1-3, characterized in that the peroxy acid 25 is a peracetic acid. A process according to any one of claims 1-3, wherein the peroxide compound is a sodium borate or sodium carbonate peroxy hydrate. 30 Process according to any of claims 1-5, characterized in that the peroxy compound is stabilized in purification or bleaching processes or in mixtures containing a peroxy compound used therein. A purification or bleaching process using a peroxy compound in solution, wherein the peroxy compound is a hydrogen peroxide, peroxyacid or a peroxyacid produced by an hydrogen peroxide activator or a hydrogen peroxide derivative and a stabilizing compound to stabilize it, characterized of using a compound of formula 1 as a stabilizing compound. 5 The method of claim 7, wherein the stabilizing compound is used simultaneously or almost simultaneously with the peroxy compound. A mixture containing a peroxy compound in which the peroxy compound is a hydrogen peroxide, peroxyacid or a peroxyacid produced with an hydrogen peroxide activator or a hydrogen peroxide derivative, characterized in that it further contains a compound of formula 1. The composition of claim 9, wherein the compound is a carboxy oxymethyl succinic acid, an oxide succinic acid or their site. 1 · *