Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C57/00—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms
  • C07C57/02—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms with only carbon-to-carbon double bonds as unsaturation
  • C07C57/03—Monocarboxylic acids
  • C07C57/04—Acrylic acid; Methacrylic acid
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/50—Use of additives, e.g. for stabilisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B63/00—Purification; Separation; Stabilisation; Use of additives
  • C07B63/04—Use of additives

Definitions

• the present invention relates to a method for preventing polymerization of a vinyl compound, and more particularly, to a distillation system in a process for producing a vinyl compound, particularly acrylic acid / methacrylic acid.
• the present invention relates to a method for preventing polymerization of a vinyl compound, which effectively suppresses the polymerization, prevents corrosion of equipment, and enables stable long-term continuous operation. Background art
• vinyl compounds such as styrene, acrylinoleic acid, methacrylic acid, ester acrylate acrylate, and acrylonitrile have been used for light or light. It is known that it has the property of being easily polymerized by heat or the like.
• various distillation operations are performed in order to separate, collect, concentrate, or purify a desired vinyl compound.
• the vinyl compound is polymerized by light or heat to form a polymer-like substance as described above, various troubles are caused in the distillation step, and the vinyl compound is prolonged. It is easy to cause unfavorable situations such as making stable continuous operation impossible for a period.
• a method of performing a distillation operation in the presence of a polymerization inhibitor has been employed.
• the polymerization inhibitor include hydroquinone and methoquinone (p-methoxyphenol).
• P-t-butyl catechol, t-butyl hydroquinone And phenothiazine are used.
• Acrylinoleic acid, methacrylic acid, etc. are very easily polymerizable compounds, and these polymerization inhibitors always provide a sufficient effect. The fact is that it has not been done.
• copper dibutyldithiocarbamate is a compound that can extremely effectively prevent the polymerization of acrylic acid and methacrylic acid in the liquid phase.
• it has fatal drawbacks such as corrosion of equipment (for example, material SUS316), and has been difficult to use in industrialized plants.
• An object of the present invention is to provide a method for preventing polymerization of vinyl compounds, which prevents equipment corrosion and enables stable continuous operation for a long period of time.
• the present inventors have conducted intensive studies to achieve the above object, and as a result, focused on an excellent polymerization preventing effect of a metal salt of dithiocarbamate represented by copper dibutyldithiocarbamate. It has been found that the purpose can be achieved by using water and a specific corrosion inhibitor such as water. The present invention has been completed based on such findings.
• the present invention relates to preventing polymerization of a vinyl compound by using a dithiocarbamic acid metal salt in a vinyl compound production process.
• the present invention relates to preventing polymerization of a bullet compound by using a metal dithiocarbamate in a process for producing a vinyl compound, and (a) an alcohol together with a metal dithiocarbamate.
• the present invention also provides a method for preventing polymerization of a vinyl compound.
• Examples of the vinyl compound to which the method of the present invention can be applied include styrene acrylate, methacrylate, acrylate, methacrylate, and acrylate. Among them, acrylonitrile and methacrylic acid are particularly preferable.
• metal dithiocarbamate is used as a polymerization inhibitor for the vinyl compound. This dichocarbamine
• R 1 and R 2 are each an alkyl group having 1 to 8 carbon atoms or a phenyl group.
• the alkyl group having 1 to 8 carbon atoms may be linear or branched, and specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group And so on.
• R 1 and R 2 may be the same or different.
• M represents a metal, such as nickel, zinc, copper, iron, and transition metals (Mn, Co, etc.).
• N indicates the valence of the metal M.
• dithiol-lubamic acid metal salt represented by the above general formula (I) examples include, for example, dimethyl dithiol-carbamic acid ⁇ , getyl dil-lactic acid rubamic acid m, and dipropyl dithiol-carbamic acid Copper oxide, dibutyldithiocarbamate, copper dipentyldithiocarbamate, copper dihexyldithiocarbamate, copper diphenyldithiocarbamate, methylethyldithiocarbamate Acid, methylpropyldithiol 'copper phosphate, methylbutyldithiolcarbamate, methylpentyldithiolcarbamate, copper methyl dimethyldithiolcarbamate.Methylphenyldithiolcarbamate.
• Copper propyl citrate Luba mate butyl pentyl dithiocarbamate Copper butyl, butyl hexyl dithiocalate, butyl phenyl dithiocalate ⁇ ⁇ ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ Iron salts.
• Various transition metal (Mn. C0, etc.) salts Among these metal salts of dithiolrubamate, copper salts of dithiolrubamate are preferred, and copper dibutyldithiocarbamate is particularly preferred.
• the metal dithiocarbamate may be used singly or in combination of two or more.
• the amount of addition is usually selected within the range of 0.01 to 11% by weight, preferably 0.05 to 0.5% by weight, based on the vinyl compound. Devour. If this amount is less than 0.01% by weight, the effect of preventing polymerization is not sufficiently exhibited. On the other hand, if it exceeds 1% by weight, the effect is not improved for the amount, but it is economically disadvantageous.
• water may be allowed to coexist with the above-mentioned metal salt of dibasic rubamate in order to suppress corrosion of equipment.
• the amount of water needs to be adjusted so as to be in the range of 0.05 to 5% by weight based on the vinyl compound. If the amount of water is less than 0.05% by weight, the effect of inhibiting corrosion is not sufficiently exhibited. On the other hand, if it exceeds 5% by weight, the separation costs a great deal of energy and is economically disadvantageous. From the standpoint of corrosion prevention and economy, the preferred water scene is in the range of 0.07 to 0.5% by weight relative to the vinyl compound.
• an alcohol in order to suppress the corrosion of equipment, (a) an alcohol, (a) an inorganic acid or a salt thereof, (c) an aromatic carboxylic acid or a At least one selected from salts and (ii) salts containing zinc may be used.
• the alcohol used as the component (a) may be, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol.
• N Butyl phenol alcohol. Isobutyl phenol alcohol, n-octyl alcohol. Primary alcohol having 1 to 10 carbon atoms such as 2-ethylhexyl alcohol, ethylene glycol cornole, propylene glycol; 1 .4 Mono-butanediol; polyhydric alcohols such as 1,6-hexanediol, phenol, cresol, xylene phenol, benzyl alcohol, phenethyl alcohol, etc. Among them, polyhydric alcohols are preferable.
• oxo acids are preferred, and specific examples thereof include boric acid, phosphoric acid, nitric acid, and sulfuric acid.
• phosphoric acid is preferred.
• salts include nickel salts, zinc salts, copper salts, iron salts, and various transition metal (Mn, C0, etc.) salts.
• aromatic carboxylic acid or a salt thereof used as the component (c) include, for example, benzoic acid, naphthalene carboxylic acid, salicylic acid, and p-hydroxybenzoic acid.
• Examples include oxinaphthoic acid and the like, nickel salts, zinc salts, copper salts, iron salts, and various transition metal (Mn, Co, etc.) salts.
• examples of the salt containing zinc as the component (2) include zinc formate, zinc acetate and zinc dithiocarbamate.
• These corrosion inhibiting substances K may be used alone or in combination of two or more.
• the amount used is based on the vinyl compound.
• the corrosion inhibitor is in the range of 0.01 to 5% by weight. If the amount is less than 0.001% by weight, the effect of inhibiting corrosion is not sufficiently exhibited, and if it exceeds 5% by weight, the effect is not sufficiently improved for the amount. May occur. From the viewpoint that corrosion is effectively suppressed and other disadvantages are not caused, the preferred amount of the corrosion inhibitor is preferably 0.01 to 3% by weight relative to the vinyl compound, Particularly preferred is a range of 0.1 to 1% by weight.
• the amount of the phosphoric acid to be used depends on the above-mentioned metal salt of dithiocarbamic acid, especially dithiocarbamic acid. It is preferable that the ratio is 0.1 or more (weight ratio) with respect to the acid copper salt.
• the metal salt of dithiocarbamic acid and water or, the treatment temperature of vinyl compounds containing dithiol metal salts of metal salts and corrosion inhibitors varies depending on the type of vinyl compound, but in the case of acrylic acid or methacrylic acid, It is usually in the range of 50 to 130 ° C. When the treatment temperature is within this range, the polymerization preventing effect and the corrosion preventing effect are sufficiently exhibited.
• Comparative Example 1 acrylic acid was replaced with copper dibutyldithiocarbamate. At the same time, 3,630 weight ppm of acetic acid manganese (relative to acrylic acid) was dissolved (water content in acrylic acid: 240 weight ppm) and added to the flask. The experiment was performed in the same manner as in Comparative Example 1 except that the gas was supplied. As a result, the weight loss of the test piece over 10 days was 0.080 g.
• Comparative Example 1 zinc dibutyldithiocarbamate 3.500 wt ppm (vs. acrylic acid) was dissolved in acrylic acid together with copper dibutyldithiocarbamate. The experiment was carried out in the same manner as in Comparative Example 1 except that water was supplied to Flasco with a water content of 970 wt ppm (vs. acrylic acid). As a result, the weight loss of the test piece over 10 days was 0.001 g.
• Comparative Example 1 100,000 ppm by weight of ethylene glycol (with respect to acrylic acid) was dissolved in acrylic acid together with copper dibutyldithiocarbamate (acrynolic acid). The experiment was carried out in the same manner as in Comparative Example 1 except that the water content of lylic acid (il 20 wt ppm) was supplied to Frasco. As a result, the weight loss of test pieces over 10 days was 0.003 g.
• Comparative Example 1 1,700 weight ppm of zinc phosphate (vs. acrylic acid) was dissolved in acrylic acid together with copper dibutyldithiocarbamate (acrylic acid). Water content in phosphoric acid: 140 ppm by weight) Other than that, the experiment was performed in the same manner as in Comparative Example 1. As a result, the weight loss of the test piece over 10 days was 0.009 g.
• Comparative Example 1 8.5% by weight of phosphoric acid (vs. acrylic acid) was dissolved in acrylic acid together with copper dibutyldithiocarbamate (acrylic acid). The experiment was carried out in the same manner as in Comparative Example 1 except that the water content in the acid was 3222 wt ppm) and supplied to Flasco. As a result, the amount of nobleness of the test piece over 10 days was 0.001 g.
• Comparative Example 1 3.300 heavy fumaric acid (vs. acrylic acid) was dissolved in acrylic acid together with dibutyldithiocarbamic acid (acrylic acid) (acrylic acid). The experiment was carried out in the same manner as in Comparative Example 1, except that the water content in the acid was 200 wt. As a result, the weight loss of the test beads over 10 days was 0.001 g.
• Comparative Example 1 100,000 ppm by weight of benzoic acid (based on acrylic acid) was dissolved in acrylic acid together with copper dibutyldithiocarbamate (in acrylic acid). The experiment was conducted in the same manner as in Comparative Example 1 except that the water content was 135 ppm by weight) and supplied to FLUSCO. As a result, the weight loss of test pieces in 10 days was 0.002 g.
• Comparative Example 1 copper dibutyldithiocarbamate was dissolved at 500 ppm by weight (based on acrylic acid) in acrylic acid, and 50 ppm Sppm (based on acrylic acid) was dissolved in acrylic acid.
• glycolic acid glycolic acid
• the inside temperature of the flask was maintained at 130 ° C. went.
• the weight loss of test pieces in 10 days was 0.0001 g.
• Comparative Example 1 copper dibutyldithiocarbamate was added to acrylic acid. Dissolve 150,000 double SppiD (vs. acrylic acid) and dissolve 40,000 double ippni (vs. acrylic acid) The experiment was carried out in the same manner as in Comparative Example 1 except that the temperature was kept at 130 ° C. and the temperature inside the flask was kept at 130 ° C. As a result, the weight loss of the test beads in 10 days was 0.022 g.
• Comparative Example 1 was the same as Comparative Example 1, except that the prescribed amounts of copper dibutyl dithiocarbamate and phosphoric acid shown in Table 2 were dissolved in acrylic acid and supplied to the flask. The experiment was performed as in 1. As a result, the weight loss of the test beads in 10 days was 0.001 g. Table 2
• the polymerization of a vinyl compound particularly in a distillation system in a production process of acrylic acid / methacrylic acid, can be effectively suppressed.
• corrosion of equipment can be prevented, and stable long-term continuous operation is possible.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Polymerisation Methods In General (AREA)

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• 1995
  • 1995-08-29 KR KR1019970701130A patent/KR100408362B1/ko not_active Expired - Fee Related
  • 1995-08-29 CN CN95194943A patent/CN1069305C/zh not_active Expired - Lifetime
  • 1995-08-29 WO PCT/JP1995/001705 patent/WO1996007631A1/ja not_active Ceased
  • 1995-08-29 EP EP95929240A patent/EP0781755A4/en not_active Ceased
  • 1995-08-29 EP EP00110689A patent/EP1043303A1/en not_active Withdrawn
  • 1995-08-29 US US08/793,600 patent/US5886220A/en not_active Expired - Lifetime
  • 1995-08-29 JP JP50936796A patent/JP3544985B2/ja not_active Expired - Lifetime
  • 1995-09-02 TW TW084109193A patent/TW289033B/zh not_active IP Right Cessation
  • 1995-09-06 MY MYPI9502643 patent/MY115982A/en unknown
• 1998
  • 1998-12-15 US US09/210,885 patent/US6051735A/en not_active Expired - Lifetime

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