JP5752579B2 - Stabilized 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl-containing composition, vinyl compound polymerization inhibitor composition, and vinyl compound polymerization inhibition method using the same - Google Patents

Description

  The present invention relates to a stabilized 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl-containing composition, which is stabilized with little decrease in the ability to inhibit polymerization even during long-term storage and storage. Further, the present invention relates to a polymerization inhibitor composition for vinyl compounds containing 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, and a method for inhibiting polymerization of vinyl compounds using the same.

  Olefins undergo radical polymerization by the action of heat, trace amounts of oxygen or peroxides, metal ions, light, and the like to produce a polymer. In order to prevent this radical polymerization from occurring in an unintended situation such as a production process, a purification process, and a storage process, it is widely known to add a polymerization inhibitor as a countermeasure. For example, in a petrochemical ethylene production process, a method using a polymerization inhibitor such as phenols, hydroxylamines (see, for example, Patent Document 1), and piperidine-1-oxyls (see, Patent Document 2) has been proposed. In particular, piperidine-1-oxyls having particularly excellent polymerization inhibiting ability have been widely used in recent years.

  However, piperidine-1-oxyls are radical compounds themselves, and when a composition in which piperidine-1-oxyls are dissolved in a solvent is stored for a long period of time, the radicals disappear and the polymerization inhibition ability decreases. In particular, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter abbreviated as “OXO-TEMPO”) is known to have a remarkable tendency.

  As a method for solving this drawback and suppressing a decrease in the ability to prevent polymerization of piperidine-1-oxyls over a long period of time, a method using alcohol as a solvent (see Patent Document 3), a piperidine-1-oxyl compound and N -Methods in which a hydroxy-2,2,6,6-tetramethylpiperidine compound and a 2,2,6,6-tetramethylpiperidine compound coexist are disclosed (see Patent Document 4). Further, it was insufficient for stabilizing OXO-TEMPO having a large degree of decrease in polymerization inhibition ability.

  Based on the above situation, at present, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter referred to as “H-TEMPO”), which has little decrease in polymerization inhibition ability among piperidine-1-oxyls, "Is abbreviated as") and is most widely used industrially as a polymerization inhibitor.

  However, this H-TEMPO is produced by hydrogenating 4-oxo-2,2,6,6-tetramethylpiperidine (also referred to as triacetoneamine, hereinafter abbreviated as “TAA”) as an intermediate. After obtaining -hydroxy-2,2,6,6-tetramethylpiperidine (see, for example, Patent Document 5), this intermediate is further oxidized with hydrogen peroxide (for example, see Patent Document 6, Patent Document 7, etc.) ), A two-step reaction step of obtaining H-TEMPO is necessary, whereas OXO-TEMPO can be produced by only one step of oxidizing TAA, and therefore, compared with H-TEMPO. And stabilized OXO-TEM that can suppress the decrease in polymerization inhibition ability even during long-term storage and storage. O-containing composition, a polymerization inhibitor composition therefrom comprising a vinyl compound, and a polymerization inhibitor of vinyl compounds using the composition has been desired.

U.S. Pat. No. 4,434,307 Japanese Patent Publication No. 4-26639 JP-A-11-171906 JP 2001-181252 A JP-A 63-303967 Japanese Examined Patent Publication No. 44-12142 JP-A-6-247932

  In view of the above circumstances, the present invention is a stabilized OXO-TEMPO composition capable of suppressing a decrease in polymerization inhibition ability even during long-term storage and storage, and a polymerization inhibitor composition of a vinyl compound containing the same. It is an object to provide a method for inhibiting polymerization of a vinyl compound using the product and the composition.

  As a result of intensive studies on the stabilization of OXO-TEMPO, in particular, prevention of a decrease in the ability to inhibit polymerization, the present inventors added H-TEMPO to the compound to stabilize it, particularly for long-term storage. -It has been found that it is possible to suppress a decrease in the polymerization inhibition ability of OXO-TEMPO during storage, and the present invention has been made.

  That is, the invention according to claim 1 is a stabilized OXO-TEMPO-containing composition characterized in that H-TEMPO is blended as a stabilizer in OXO-TEMPO.

  Invention of Claim 2 is a composition of Claim 1 formed by mix | blending 0.01 weight part or more of H-TEMPO with respect to 100 weight part OXO-TEMPO.

  Invention of Claim 3 is a composition of Claim 1 or 2 formed by mix | blending 10-500 weight part H-TEMPO with respect to 100 weight part OXO-TEMPO.

  The invention according to claim 4 is the composition according to any one of claims 1 to 3, further comprising a solvent of OXO-TEMPO and H-TEMPO.

  The invention according to claim 5 is the composition according to claim 4, wherein the solvent is a mixed solvent of water and an alcohol compound.

  The invention according to claim 6 is a polymerization inhibitor composition of a vinyl compound in which 0.01 part by weight or more of H-TEMPO is blended with 100 parts by weight of OXO-TEMPO.

  The invention according to claim 7 is the polymerization inhibitor composition of vinyl compound according to claim 6, wherein 10 to 500 parts by weight of H-TEMPO is blended with 100 parts by weight of OXO-TEMPO.

  The invention according to claim 8 is the vinyl compound polymerization inhibitor composition according to claim 6 or 7, further comprising a solvent of OXO-TEMPO and H-TEMPO.

  The invention according to claim 9 is the polymerization inhibitor composition of vinyl compound according to claim 9, wherein the solvent is a mixed solvent of water and an alcohol compound.

  An invention according to claim 10 is a vinyl characterized in that the polymerization inhibitor composition according to any one of claims 6 to 9 is added directly to a fluid containing a vinyl compound or further diluted in a solvent. This is a method for inhibiting polymerization of a compound.

  By stabilizing the OXO-TEMPO according to the present invention, it is possible to suppress a decrease in the polymerization inhibition ability even during long-term storage and storage, which is advantageous in terms of cost compared to conventional general-purpose H-TEMPO. A vinyl compound polymerization inhibitor composition can be provided.

  The stabilized composition of the present invention contains OXO-TEMPO and H-TEMPO as its stabilizer, but the content ratio is 0.01 weight of H-TEMPO with respect to 100 weight parts of OXO-TEMPO. If it is less than 10 parts by weight, it may not be possible to suppress a decrease in the ability to inhibit the polymerization of OXO-TEMPO during long-term storage / storage. Therefore, it is preferable to contain 0.01 parts by weight or more of H-TEMPO, especially 10 parts by weight. It is more preferable to contain the above. Moreover, when the content ratio exceeds 500 parts by weight of H-TEMPO with respect to 100 parts by weight of OXO-TEMPO, an effect corresponding to the increase in the content of H-TEMPO cannot be obtained, which is economically disadvantageous. is there.

  When used as a polymerization inhibitor for vinyl compounds, it contains a solvent in addition to OXO-TEMPO and H-TEMPO, and the solvent includes conditions such as the production apparatus, storage device, and transportation means of the vinyl compound to be applied. The solvent can be appropriately selected according to the above, and an aromatic solvent, an aliphatic solvent, water, an alcohol compound, a process liquid of a manufacturing apparatus, or the like can also be used. For example, in the butadiene production process, toluene is an aromatic hydrocarbon contained in the process liquid without selecting water or an alcohol compound, especially because it does not like mixing into a product. Moreover, there is no restriction | limiting also in mixing and using 2 or more types of solvents.

  Examples of the aromatic solvent or aliphatic solvent used in the present invention include benzene, toluene, xylene, ethylbenzene, other aromatic compounds, naphthene hydrocarbon compounds, mineral oil, paraffin hydrocarbon compounds, and the like. Moreover, as water, normal industrial water, softened water, ion-exchange water, etc. can be used. Furthermore, as alcohol compounds, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tertiary butanol, 1-pentanol, 3-methyl-1-butanol, 3-pentanol, n-hexanol, 2-ethylbutanol, n-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, ethylene glycol, ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether Diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, polyethylene glycol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, butanediol, pentanediol, glycerin, cyclohexanol, 2-methyl Examples include cyclohexanol, benzyl alcohol, and phenol.

  The kind and blending amount of the solvent in the polymerization inhibitor composition of the present invention are appropriately selected in consideration of the solubility and product stability of OXO-TEMPO and H-TEMPO blended simultaneously. As will be apparent from Examples below, a mixed solvent of water and an alcohol compound is excellent in solubility and product stability of OXO-TEMPO and H-TEMPO, and also has an effect of suppressing a decrease in polymerization inhibition ability of OXO-TEMPO. . These effects are synergistic effects that cannot be obtained with water alone or alcohol alone, and a particularly preferred combination and blending amount are water: ethylene glycol monobutyl ether = 50: 1 to 1:50 (weight ratio). In addition, the above-mentioned synergistic effect that suppresses the decrease in polymerization inhibition ability due to the mixed solvent of water and an alcohol compound is not limited to the combined use of OXO-TEMPO and H-TEMPO, but OXO-TEMPO alone, H-TEMPO alone, and It is also exhibited when dissolving other piperidine-1-oxyls.

  A preferred example of the composition of the polymerization inhibitor composition is 1 part by weight of OXO-TEMPO, 1 part by weight of H-TEMPO, 2 parts by weight of water, and 1 part by weight of ethylene glycol monobutyl ether.

  The production of the polymerization inhibitor composition of the present invention can be achieved by adding H-TEMPO to a solvent at room temperature to dissolve, and further adding OXO-TEMPO to dissolve and stir to mix uniformly. There is no particular limitation on the order of dissolving each component, and there is no limitation on the device such as changing the mixing order depending on the physical properties of each component, but the ability to prevent polymerization of OXO-TEMPO during the production of the composition In order to prevent the decrease, it is necessary not to heat OXO-TEMPO to the melting point (37 ° C.) or higher.

  If necessary, other known polymerization inhibitors, antioxidants, metal deactivators, dispersants and the like may be added to the polymerization inhibitor composition of the present invention.

  The application of the polymerization inhibitor composition of the present invention is not particularly limited. For example, during the petrochemical process, the production, purification process, transportation, and storage of various vinyl compounds, contamination due to polymerization of the vinyl compound is suppressed. In order to suppress the decrease in the yield of the vinyl compound due to polymerization, it is preferable to add to the equipment where polymerization occurs, for example, in a heat exchanger, reboiler, piping, storage tank, and / or upstream thereof. At this time, the amount of addition of the polymerization inhibitor composition of the present invention varies depending on the type of vinyl compound and process conditions, and cannot be determined uniformly. However, the total amount of OXO-TEMPO and H-TEMPO is determined as the total amount of the process fluid. It is common to add so that it may become 0.1-1000 ppm with respect to.

  In general, the polymerization inhibitor composition of the present invention is diluted with a stock solution or a solvent, and a chemical injection pump is used to select continuous or intermittent addition according to the type of vinyl compound and process conditions. be able to. The solvent used for the dilution can be used without limitation as long as it is a solvent used for the polymerizing agent composition or a solvent that is compatible with the solvent. Done.

  There are no restrictions on the types of vinyl compounds that can be used, olefin compounds such as ethylene, propylene, butylene, and isobutylene, substituted or unsubstituted conjugated diolefin compounds such as butadiene, isoprene, and chloroprene, styrene, and α-methylstyrene. , Aromatic vinyl compounds such as divinylbenzene, methacrylic acid esters and methacrylic acid compounds such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, allyl methacrylate, 2-hydroxyethyl methacrylate, 2- (dimethylamino) ethyl methacrylate Acrylates and acrylic compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, acrylonitrile, methacrylonitrile Any cyanide vinyl compound, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 2- (5-norbornenyl) ethyl (dimethyl) methoxysilane, 5-hexenylmethyldimethoxysilane, 3-acryloxy Propylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltris (trimethylsiloxy) silane, 4-ethenylphenyltrimethoxysilane, 2- (4- Ethenyl unsaturated group-containing silane or siloxane compounds such as ethyltriethoxysilane, vinyl ester compounds such as vinyl acetate, vinyl chloride, vinylidene chloride, vinyline fluoride, tetrafluoro Examples thereof include halogenated olefins such as fluoroethylene and hexafluoropropylene.

1. Compounds [piperidine-1-oxyls] used in the test
N-1: 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (OXO-TEMPO)
N-2: 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (H-TEMPO)
N-3: 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl N-4: 4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl N-5: 2,2,6,6-tetramethylpiperidine-1-oxyl

[solvent]
S-1: Xylene S-2: Kerosene S-3: 2-Ethylhexanol S-4: Ethylene glycol monobutyl ether (hereinafter abbreviated as “EGB”)
S-5: Water W-1: Water: EGB = 1: 50 (weight ratio) mixed solvent W-2: Water: EGB = 1: 1 (weight ratio) mixed solvent W-3: Water: EGB = 2 : 1 (weight ratio) mixed solvent W-4: Water: EGB = 50: 1 (weight ratio) mixed solvent

2. Test Method A composition in which piperidine-1-oxyls and various solvents are mixed at a predetermined ratio is allowed to stand in a thermostat at 50 ° C. for 10 days, 20 days, and 30 days, respectively, and 4-oxo- The concentration of 2,2,6,6-tetramethylpiperidine-1-oxyl (OXO-TEMPO) was measured by gas chromatography, and compared with the concentration when the composition was prepared, OXO-TEMPO residual rate (%) Asked. It is shown that the larger the residual ratio, the smaller the decrease in polymerization prevention ability of OXO-TEMPO (= the greater the effect of suppressing the reduction in polymerization prevention ability).

  From the results shown in Table 1, it was confirmed that OXO-TEMPO has a large decrease in polymerization preventing ability compared with other piperidine-1-oxyls.

  From the results shown in Table 2, by allowing 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (H-TEMPO) to coexist with OXO-TEMPO, other piperidine-1-oxyls Compared with the case of coexisting, specifically, the decrease in the ability to prevent polymerization can be significantly reduced, and the stabilization effect of OXO-TEMPO by H-TEMPO was confirmed.

  From the results shown in Table 3, it was confirmed that the decrease in the ability to prevent polymerization of OXO-TEMPO can be reduced by coexisting 0.01 part by weight or more of H-TEMPO with respect to 100 parts by weight of OXO-TEMPO. . The greater the coexistence content of H-TEMPO, the greater the inhibitory effect of OXO-TEMPO on the ability to prevent polymerization, and when H-TEMPO is contained in an amount exceeding 500 parts by weight, the merit that is commensurate with it is enjoyed. It is difficult and economically disadvantageous.

  From the results shown in Table 4, in Examples 11 to 14 using a mixed solvent of water and an alcohol compound (W-1 to 4), Example 10 or an alcohol compound using water alone (S-5) as a solvent. The synergistic effect that OXO-TEMPO has a lower inhibitory effect on polymerization inhibition than that of Example 8 and Example 9 using a single substance (S-3, S-4) as a solvent, and cannot be obtained with a single solvent of water or an alcohol compound. Effects were recognized. It was shown that the preferred blending ratio of water and alcohol compound is water: EGB = 50: 1 to 1:50 (weight ratio), and the particularly preferred blending ratio is water: EGB = 2: 1.

Claims (10)

  4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl is blended with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl as a stabilizer. A stabilized 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl-containing composition.   0.01 parts by weight or more of 4-hydroxy-2,2,6,6-tetramethylpiperidine-based on 100 parts by weight of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl The composition of Claim 1 formed by mix | blending 1-oxyl.   10-500 parts by weight of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1 to 100 parts by weight of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl The composition according to claim 1 or 2, comprising -oxyl.   The solvent further comprises 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The composition in any one of thru | or 3.   The composition according to claim 4, wherein the solvent is a mixed solvent of water and an alcohol compound.   0.01 parts by weight or more of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1 with respect to 100 parts by weight of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl -A vinyl compound polymerization inhibitor composition comprising oxyl.   10-500 parts by weight of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1 to 100 parts by weight of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl The polymerization inhibitor composition of a vinyl compound according to claim 6, wherein -oxyl is blended.   7. A solvent further comprising 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Or a polymerization inhibitor composition of a vinyl compound according to 7.   The vinyl compound polymerization inhibitor composition according to claim 8, wherein the solvent is a mixed solvent of water and an alcohol compound.   A method for inhibiting polymerization of a vinyl compound, comprising adding the polymerization inhibitor composition according to any one of claims 6 to 9 directly to a fluid containing a vinyl compound or further diluted in a solvent.