JPH06506001A - Stabilizing compositions for S-substituted aldehydes, processes for stabilizing aldehydes and stabilized aldehydes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention can be used in various temperature and humidity conditions in the presence or absence of carbon steel. and beta-methyl-thio-propionic aldehyde (MTPA). Stabilizing composition to prevent S-substituted aldehyde from deteriorating Furthermore, the stabilization process using the proposed stabilizing composition and the stabilized Regarding aldehydes.

Background technology Aldehydes usually absorb oxygen during storage and undergo a series of reactions characterized by quality deterioration. cause. In the prior art, additives for stabilizing aldehydes include: Many proposals have already been made.

a) Aromatic or aliphatic, such as pyridine, quinoline, dialkylamine, etc. amine, MTPA, preferably 2. Addition of 000ppm.

1929 U.S. Patent No. 1. 736. No. 747 already has 1,2-diamino Addition of ethane, i.e. 0.25-1.0% of 1,2-di(phenylamino)ethane proposed stabilization of aldehydes against oxidation by Japanese 1972 patent Publication No. 032963 discloses that 0.1 of pyridine, quinoline, collidine or lutidine discloses stabilization of MTPA by addition of %. Yet another Japanese 1974 patent Public Notice No. 116017 (September 27, 1974) is published by N. N-dialkylaniline It is proposed to stabilize MTPA by adding 0.2% of MTPA. And finally in 1945 No. 2 US Patent of 2013. No. 381, 771 applies to rubber, glue, petroleum and their derivatives. (gasoline, aldehydes) as an antioxidant, especially quinoline, ated dihydroxy.

b) Alkanolamine Perfumer, 46 (7), 33-5. 1944 author, Sagarin ε, and H, M refer to the use of alkanolamines for the stabilization of aldehydes. and for the same purpose alkyl-substees.・Tuted Fe We recommend using Nord.

USSR Patent No. 568.629 discloses that triethanolamine is added by 0.25-0.5%. Formaldehyde stabilization suppresses the production of formic acid and methanol by clarifying the law.

C) Unsaturated tetrasubstituted compounds Such stabilizers are 75.235.

d) Phenolic compounds (phenol, naphthol, etc.) and amines (pyridine, based on picoline, lutidine, collidine, quinoline, or mixtures thereof) The composition preferably contains 1.000 ppm of 4-methoxyphenol and pyridine. The system is based on S-substituted aldehyde such as MTPA. Such compositions are described in Pennwalt's U.S. Patent No. 4.5. No. 46.205 (PI 8301502).

The stabilizer compositions proposed in the prior art have a number of drawbacks. They are For example, it contains toxic amines, has a relatively low boiling point compared to aldehydes, and However, such compositions may interfere with distillation prior to their use in synthetic routes. It may cause damage. The extent of such impairment is determined by the relative molecular weights of the product and stabilizer ( and boiling point).

Disclosure of invention Roughly speaking, the decomposition of aldehydes is an autooxidation process that occurs following the absorption of 0□. , by aldol condensation and optionally by thermal decomposition.

The main mechanism of decomposition of S-substituted aldehyde is a) free radicals absorption of 02 and autoxidation by contact with metals, with propagation by.

b) Aldol condensation in acidic media; cyclic trimerization and polymerization.

C) A thermal decomposition reaction that takes place with or without the catalysis of a metal. stabilized In the case of MTPA without MTPA, methylmethane is extracted from MTPA itself and its thermal decomposition products. Lecaptan, acrolein, water and ethylene are produced.

d) Nucleophilic addition and substitution. In the case of MTPA, from mercaptans and thioesters Generated from the resulting decomposition product methyl mercaptan.

e) decarbonylation reactions, e.g. with the formation of non-carbonyl organic sulphides. CO withdrawal reaction These five types of reactions probably work together and are caused by a chain reaction. compared to other carbonylic compounds, it has a much greater ability to prevent the oxidation of vegetable oils. Recommended as an inhibitor (Journal Amer, Oil Chem, Soc, , 1977, 54. p, 4-), such as MTPA. The oxygen uptake capacity exhibited by bus-stated aldehyde is illustrated.

The presence of oxygen, contact with metals and thermal factors, alone or in combination, can cause S substituents to Particular emphasis is placed on causing the decomposition of fused aldehydes.

The diagram below shows the combined mass spectroscopy under the conditions shown below. Possible solutions for the decomposition of MTPA, for example, based on gas chromatographic analysis Indicates a certain route.

Chart 1 (1/4) Chart 1 (2/4) Chart 1 (3/4) Chart 1 (4/4) adjusted. Afterwards, the MTPA peroxyacid, which becomes MTPA acid, is produced. or chemical compounds such as mercaptides that produce disulfides and heavy compounds. A reaction that produces .proceeds.

A, ], 2. −　　　　　　　　　　　　　　　　 eno It depends on the stability of the MTPA.

Diagram 2 (A, 1.2.) The reaction between MTPA and its decomposition products becomes significant at temperatures above 65°C. metal The presence of promotes this type of reaction. This thermal decomposition consists of A.1. 1. and A , 1°Z, and the release of methyl mercaptan in the organic solvent causes A, 1 ．． 4. cause a type of reaction.

A.1. 4. - Addition and substitution: Methyl mercaptan is a mercapdol and hemitioacetal type addition. produce a compound. Thioether type compounds in the presence of carboxylic acids Produced by reaction.

Chart 2 (A, 1.4,) A.1. 5. − Theory Carbonyl reaction: The existence of mercabutane is due to the facilitates the decarbonylation of aldehydes, especially as in the case of MTPA, and to produce the corresponding organic sulfide.

Diagram 2 (A, 1.5.) The first step of MTPA decomposition involves the absorption of oxygen, which increases the strength of the enol form of MTPA. autoxidation, which is facilitated by high stability. Then in acidic solvent Aldol condensation occurs, resulting in peroxyacids or corresponding carboxylic acids. It is catalyzed by its own acidity. Thermally controlled decomposition of MTPA and and/or MTPA peroxyacids, methyl mercaptan, acro produces rhein and ethylene.

In a study of the thermal decomposition of MTPA in an inert atmosphere, it was found that heating was not possible at temperatures below 90°C. It has been shown that the production of mercaptans is small. Of course, Above 105°C thermal decomposition becomes a critical factor for the stability of this molecule.

Applicant's experimental results show that in an oxygen atmosphere, peroxygen Due to the involvement of acids, pyrolysis to release methyl mercaptan is easier and at lower temperatures. It is clear that this occurs even in

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides an S-substituted aldehyde having 4 to 4 carbon atoms. 15 and is represented by general formula (1).

R1=C+ Cs alkyl, C, -C, allyl, furfuryl and benzyl , and a prototropic agent (A) with an oxygen scavenger (B) selected from the table below. ).

Table A/B A.1. : Aromatic or B, 1. :Substituted Heterosci Click Aromatic Phenol or Hydroquinone Amine, e.g. gin, such as pt-butylphenol dimethylaniline, (PTBF) , BHT (2,6 ditelquinoline, 8-hydroxyquinoline butyl, 4- methylphenol) collidine, vinyline, lutidine A.2. : alkanolamine or B, 2. : Acid or unsaturated antioxidant, non-oxidant - Aromatic cyclics such as ascorbic acid (AA), amines, e.g. For example, triethanolamine beta carotene (TEA), N-methylmorpholy hmm A.3. :lactam, e.g. N-methylpyrrolidone The stabilizer composition consists of the following two combinations: A=pyridine, B=p-t-butyl tylphenol, and two sets of A=quinoline and B=p-t-butylphenol. Made from A and B, except for combinations.

Preferably, the following stabilizer compositions are indicated.

TEA/AA is particularly suitable as composition A/B.

The role of prototropic agents is the acid center responsible for addition aldol condensation. The role of oxygen scavenger B is to remove The purpose is to prevent the occurrence of undesirable reactions in the aldehyde.

Stabilizer composition for S-substituted aldehyde of formula (1) is added at a concentration of 500 to 1500 ppm, preferably too ppm. Ru. The molar ratio of A/B components is between 5/95 and 5150. Desirable stabilizer The composition contains 1000 ppm TEA/A with 10-50% AA in TEA. This is composition A.

Regarding the use of isolated amines, the synergistic effect of stabilizer compositions is based on the state of the art. This usually indicates the presence of decomposition products, as described in Table 1 of the Examples. Stabilized S-substituted alde which appears without yellowish color Hido attracts attention. When the stabilized aldehyde is subjected to chromatographic analysis, , almost no components resulting from changes in the aldehyde itself are found. that Stabilization is extremely effective against these. In the stabilizer composition, components A and B are distillation residues. The subsequent handling of the stabilized aldehyde is There is no problem.

Stabilization has been proven to be effective at various temperatures (see Table 2 in the Examples) For example, MTPA stabilized with TEA/AA and kept at 50°C for 15 days is The decrease was limited to less than 2% during the storage period.

The present invention is also characterized in that an A/B stabilizer composition as described above is added, The present invention relates to a method for stabilizing the S-substituted aldehyde shown in 1).

Effect of moisture content The presence of water in the S-substituted aldehyde or composition thereof affect the stabilization ability of the A/B system. Mainly aldehydes are metal or is in contact with carbon steel, under such conditions the amine type component A Generates OH ions that promote rudol condensation.

In the case of TEA, the following reaction occurs in the presence of water.

N (CH, CH, OH), +H! 0 −-→　HN” (CH, CH, OH), +OH- promoted in alkaline solution The aldol mixing reaction gives rise to MTPA (especially when carbon steel is present in the solution). On the other hand, it is expressed by the following formula.

H*C-5-CH, -CH, -COH+ OH''--→ H, C-3-CH, - CH, -COHθ That is, the presence of water increases the stability of the S-substituted aldehyde. It must also be kept to a minimum in the composition. S subs shown by formula (1) The process for stabilization of posed aldehydes requires a stabilization temperature of 50″ C or less, the water content in the aldehyde is at most 300 ppB, preferably l10 Limited to 0 pP or less.

Addition to S-substituted aldehydes in industrial processes During production, water is produced as a decomposition product immediately after initial distillation and transfer to storage tanks. It is recommended that this be done before

Carbon steel Experimental observations have shown that carbon steel has a It shows two remarkable effects.

1) T<50℃: Carbon steel is an oxygen isolator due to the steel surface's ability to extract oxygen from the solvent. Stabilizes the aldehyde with respect to its action. More specifically, M.T. Regarding PA, it is caused by metal ions due to the action of its enol. Autoxidation will probably occur.

2) T>50℃: Carbon steel contributes to the decomposition of aldehydes, especially in the presence of oxygen. MTPA In the case of , the generated methyl mercaptan or enol attacks the steel surface, and divalent and trivalent Fe ions and divalent Fe ions that catalyze aldehyde oxidation products. Generates valent Mn ions.

Stabilization process proposed for S-substituted aldehyde (1) It does not matter whether or not there is contact with carbon steel.

The proposed A/B stabilizer composition was ), the decomposition of S-substituted aldehydes in the presence of carbon steel Reduce products. The stabilization process used for aldehydes ranges from 25 to Applicable in a temperature range of 100°C.

The S-substituted aldehyde of formula (1) can be prepared as described above (, A/B stabilizer composition.

l) Synergy of stabilization systems MTPA samples, stabilized or not, were weighed and placed in a glass amplifier. or “Pal Pump 1 (Teflon ampoule with exterior lining of carbon steel)” Packed, sealed and heated in the stove for a certain period of time in the atmosphere by refracting the light rays It was done. The sample shows the synergistic effect of compositions A+B and those listed in Tables A/H. Oxymation and/or gas chromatography to check the quality stabilization function. analyzed by graphics.

For comparison, each test was performed on unstabilized MTPA heat treated under the same conditions. It was compared with the comparative test example by. Each test and each comparison test is conducted at repeated temperatures. It was.

Samples are prepared by weighing on a chemical analytical or microanalytical balance and are prepared using the appropriate composition. Tested as a stabilizer in MTPA in the range of 1000 to 2500 ppm. It was. Tests were conducted at 50°C, 180°C and 120°C, and also at room temperature. It was also carried out in

Analysis method gas chromatography Analysis by gas chromatography is based on 100% normalization. to determine the composition of MTPA and the chromatographic aspect of the sample. Ta.

Amount delivered by oximation The MTPA component was obtained by functional analysis using the potentiometer method.

result Table 1 lists the test conditions (time, temperature, stability) for each sample and the corresponding stabilizer. amount of agent), -Initial components of MTPA - MTPA component after heating for a certain period of time −Sample color tone -Decomposition and stability ratio of MTPA - Chromatogram showing impurity formed Aspect impurity with molecular weight 190 (M The relative production ratio of TPA chromomers) was selected as being indicative of MTPA degradation products. It was done.

- Determined as the ratio of the amount of change between the unstabilized MTPA component and the stabilized MTPA component. Stabilization factor determined Yun-yo MTPA stabilization test First, despite its strong absorption of oxygen, the acid actually undergoes an aldol condensation reaction. Add only ascorbic acid to stabilize the aldehyde as it promotes That is not shown.

The synergistic effect of A/B components on MTPA stabilization is particularly important in the prior art Regarding amines such as lysine, quinoline and dimethylaniline, their This is much clearer than when the substances are added separately. Moreover, A/B stability The amount of stabilizer in the system is less than suggested by these prior art. The quantity is sufficient.

Stabilizer mixtures were tested at stabilizer concentrations by weight for aldehydes. 1000.2000 and 2500ppm, molar ratio in TEA is 10%, 2 They were 0% and 50%.

Triethanolamine has low toxicity, produces virtually no odor, and has a higher It has a high boiling point (206℃ at 15mmHg) and is actively used for industrial purposes. Recommended.

2) TEA/AA test More precise testing was performed on the TEA/AA stabilization system.

Samples were prepared at the mass and molar ratios shown below.

9.6 mg ascorbic acid (0,055 tn mol) in MTPAI00mf and 90.4 mg triethanolamine (0,603 mmol), actual The molar ratio used was 8.4 mol% ascorbic acid and 9 mol% triethanolamine. 1.6 mol%.

Tests were conducted at 50.80 and 100’C and the heating period was 360 hours (15 days). It reached .

The data obtained are shown in Table 2. where each number has good relative accuracy This is the average value of two repeated tests.

MTPA content was determined by gas chromatography and oximation.

For reference, MTPA in contact with carbon steel in the presence and absence of a stabilizer composition is shown below. The data obtained from the 50°C test are also shown.

MTPA content was determined by gas chromatography and oximation.

For reference, MTPA in contact with carbon steel in the presence and absence of a stabilizer composition is shown below. The data obtained from the 50°C test are also shown.

Table 2 (1/4) Table 2 (2/4) Table 2 (3/4) Table 2 (4/4) From Table 2, the effective behavior of this stabilizer composition can be seen. That is, the initial concentration When heated for 15 days under the same conditions for 98.01% MTPA, the stabilizer This stabilizer composition dropped to 78%, whereas without the addition of When added, the concentration was kept at 97%, essentially unchanged from the initial concentration.

This composition is also effective in stabilizing MTPA in contact with carbon steel at 50°C.

The physical and chemical data graph for stabilization correlates with the data shown in Table 2. Indicates the person in charge. Here, ■ is the test result of stabilized MTPA at 50°C■ is the test result of non-stabilized MTPA at 50℃■ is the test result of stabilized MTPA at 80℃ MTPA test result at 80°C is stable. The test result at 100°C for stabilized MTPA is 100°C for unstable MTPA. These are test results at °C.

Here, the linear correlation between MTPA concentration and time values at 50°C and 80°C is shown. It is shown. The correlation at 100°C is not linear. of the mechanism Mutual interference between the two, especially thermal decomposition, occurs at this temperature; This suggests that it will not occur.

Calculation of initial rate constants at three temperatures for unstabilized and stabilized MTPA The data shown in Table 3 are derived.

Neyu Dynamic data for unstabilized and stabilized MTPA - initial rate constant at each temperature* Stabilizer: molar ratio 10% ascorbic acid -11000pp) Reethanola The value of Min**K was calculated from the data at zero time and after 67 hours in Table 2. Pseudo-order initial rate constant.

The activation energy values of the two states are calculated from the values shown in Table 3 as follows: .

Activation energy - Unstable MTPA decomposition - 10.5 Kcal/mol activity Sexualization energy - Stabilized MTPA decomposition...25.5 Kcal/mol, i.e. , kinetically and thermodynamically, MTPA stabilization by TEA/AA stabilizer compositions , is equivalent to increasing the activation energy by a factor of 2.5, and this value Determines the degree to which the composition is blocked by the presence of the stabilizer.

Extrapolation calculation from the data in Tables 2 and 3 based on the formula log K = f (1/T) Then, the rate constant of the stabilized aldehyde at 30"C is = 1.1 5xlO-'/Hr is obtained. This value predicts MTPA in the presence of stabilizers. The rate of wear and tear under environmental conditions! The amount of loss is less than 1% after a month of storage. It means that.

3 Effect of stabilization system on S-substituted aldehyde distillation Testing of light, distillate TEA/AA stabilizer compositions in MTPA fractionation and the mass distribution in the distillation residue. The high boiling point of AA is due to the presence of this component in the distillation residue. Monitoring of stabilizers is limited to TEA tracking, allowing the assumption that It was held.

The test was conducted using a tube with an outer diameter of 5 cm and a height of 7 Teflon piercing plates fitted into it. It was carried out by intermittent fractionation in a 65C11 tall glass column.

MTPA5.97f (6210g) immediately after 90.0% distillation and TEA5.58g (990ppm) and 8 people 0.62g (100ppm) and 39 am Hg, distilled at 91"C. Light components equivalent to 18% of the total and total weight The three continuous distillation components, which account for 77.7% of the total, and the residue, which accounts for 3.4% of the total, are collected. I was caught.

TEA is determined potentiometrically using 0.01N perchloric acid in acetic acid as the titrant. was titrated. At the same time, a blank test was conducted on Specimen as described above. It was shown that the TEA addition limit under these conditions was 10 ppm. obtained The results are shown in Table 4.

*Not detected by potentiometric titration method.

From the table above, it is clear that under the above conditions, all TEA remains in the distillation residue. do. Therefore, the components of the proposed stabilizer composition remain in the residue even during continuous distillation. It is thought that it will remain in the

Stabilizing effect in an inert atmosphere at 37°C in the presence and absence of carbon steel 120B+ = long-term testing in the presence and absence of carbon steel and in an inert atmosphere MTPA at 37°C in the presence and absence of a stabilizing system at Decomposition was carried out to determine.

100% initial component (retained in N! gas) M microdistilled in N2 gas TPA with and without carbon steel specimens N! with gas saturated atmosphere Filled into a glass ampoule. 9ooppm TEA and 100ppa+ A A stabilizer composition was used.

From the results shown in Table 38, the following is known.

a) Decomposition becomes important during the storage period from 15 days to 1 month at that temperature. Become. This suggests a strong catalytic effect due to its own decomposition composition.

b) System stabilizing effect: For unstabilized products, there is an average of 17% degradation during a three-month storage period. However, during storage for the same period, only 7% decomposition occurred.

C) Stabilization of MTPA in the presence of carbon steel Presence of carbon steel in an inert atmosphere Degradation and stabilization of MTPA in presence and absence Test at 37°C (2/3) MTPA - Distilled and redistilled samples at test preparation port - Nitrogen atmosphere - Inert air Prepared throughout the body.

Carbon steel +020 The method used for the determination of MTPA components was standardized liquid chromatography ( HPLC).

Equipment: HPLC-Varian 5010 or equivalent. .

Column: Lichrosorb RP18, length = 30cm, inner diameter = 0.4 cm moving stage: Acetonitrile/H20, 1:9v/v dispatcher Aji: 1.2 m I! /min.

Detection: 200 r+m ultraviolet light Dilution of measurement solution: 0.1% in acetonitrile Injection volume: 10 ul Retention time: Approximately 8 minutes Inch Greater: HP3390 Dosage with external calibration: MTPA standards are based on double distillation and nitrogen in the refrigerator. Obtained by storage in elementary gas, containing 900 ppm TEA and 100 ppm A It was stabilized by A.

There is no experiment similar to that described in l) 1 Dynamic activity of the stabilizing system above. It was. MTPA dose for oximation and gas and liquid chromatography (see section on chromatograms).

For tests conducted in the presence of carbon steel, the test specimen was housed inside the ampoule. container, sealed, and heated for a period of time. TEA/AA system is loopop It was used in pm.

Table IA Effect of MTPA-TEA-AA stabilizer in the presence of carbon steel T5 0°C: Decreased amount of MTPA component and generation of impurities detected by chromatogram The velocity is clearly reduced by contact with carbon steel compared to MTPA alone (39.9% absolute difference in component values at room temperature).

At room temperature, when the stabilizer is active, M after 1.080 hours (45 days) The TPA composition is the same whether or not carbon steel is present.

T>50°C: Steel has a strong positive effect on the decomposition of aldehydes. experimental of MTPA after 360 hours at 80°C when carbon steel is present. The composition will be 6°4%, but if carbon steel does not exist, it will be heated under the same temperature conditions and for the same time. The MTPA component after the elapsed time is 65.5%. At 100℃, this effect is even more pronounced. appear strongly. Under these conditions, the stabilizer is effective at 80°C. Stabilization The calculated MTPA content shows a higher value than the unstable MTPA when carbon steel is present. .

Therefore, in the presence of carbon steel and at various temperatures, this stabilizer It can be said that it is effective in inhibiting the decomposition of hydrated aldehyde.

moisture 1) Presence of generated moisture and 90% TEA-10% AA mixture too l) I) m MTPA decomposition test at 50°C and 80°C under conditions High-resolution liquid chromatography (HPLC) was used to analyze samples under the conditions described above. The MTPA component was analyzed.

Table 2A shows the negative effect of moisture on stabilization at the test temperatures.

Table 2A -Initial MTPA component: too, o% -TEA-trithia/-ruamine (900ppm); A, A, -ascorbi Acid (100ppm) - Dosage by HPLC external standard -Tests conducted in nitrogen The numbers indicate the results of two tests performed simultaneously.

As in the previous test, the samples were subjected to chromatographic analysis under the conditions already mentioned. MTPA content was measured. Here are the effects of water and steel on MTPA. Ru. (Table 4A) -MTPA initial component (HPLC): 100.02% -PY is pyridine 900pp m: A, A, ascorbic acid 1100 pp test was conducted in nitrogen.

The test results correspond to two tests performed simultaneously.

International i+i*m loss

Claims (1)

[Claims] (1) Specially characterized in that it is based on a prototropic agent (A) with an oxygen scavenger (B). S substance having 4 to 15 carbon atoms represented by general formula (I) Stabilizer composition for dooraldehyde. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ However, here, R1=C1-C5 alkyl, C6-C9 allyl, furfuryl and benzyl R2= H, R1 R3=H, R1 It is. (2) Component (A) is selected from among the substances that constitute Group A below, and Component (B) is selected from among the substances constituting Group B below. A stabilizer composition for S-substituted aldehydes according to claim 1. However, A=pyridine, B=pt-butylphenol, and A=quinoline, B = Excluding the two sets of pt-butylphenol combinations. Group A Aromatic or heterocyclic aromatic amines, e.g. pyridine dimethylaniline, quinoline, 8-hydroxyquinoline collidine, picoli hmm alkanolamines or non-aromatic cyclic amines, e.g. Ethanolamine (TEA), N-methylmorpholine lactam, e.g. Chilpyrrolidone group B Substituted phenol or hydroquinone e.g. p-t butyl phenol Nor (PTBF), BHT (2,6 di-terbutyl, 4-methylphenol) acids or unsaturated antioxidants, such as ascorbic acid (AA), beta-carotene ( 3) According to claim 1 or 2, component (A) is TEA and component (B) is AA. A stabilizer composition for S-substituted aldehydes. (4) Added in an amount of 500 to 1,500 ppm, preferably 1,000 ppm. The S-substitute according to any one of claims 1 to 3, characterized in that: Stabilizer composition for aldehydes. (5) The molar ratio of components (A)/(B) is from 5/95 to 50/50. The S-substituted aldehyde according to any one of claims 1 to 4, wherein Stabilizer composition against dehydration. (6) Adding stabilizer compositions (A)/(B) as described in claims 1 to 5. of the S-substituted aldehyde represented by the general formula (I), characterized by Stabilization process for. (7) When the stabilization temperature is 50°C or higher, the aldehyde is anhydrous or The water content is 300 ppm or less, preferably 100 ppm or less. S-substituted alcohol represented by general formula (I) according to claim 6, Stabilization process for dehydes. (8) A claim characterized in that the temperature at which the aldehyde is placed is 25 to 100°C. S-substituted alcohol represented by general formula (I) according to claim 6 or 7 Stabilization process for dehydes. (9) Any of claims 6 to 8, characterized in that the aldehyde is in contact with carbon steel. S-substituted aldehyde represented by general formula (I) according to any one of Stabilization process for. (10) Contains the A/B stabilizer composition according to claims 1 to 5, or claim 6. 4 carbon atoms represented by general formula (I) stabilized by the process described in 9 to 9 to 15 S-substituted aldehydes. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ However, here, R1=C1-C5 alkyl, C6-C9 allyl, furfuryl and benzyl R2= H, R1 R2=H, R1 It is.