RU2054429C1 - Method for production of antiseptic agent for protection of wood - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: desired product is boron-containing antiseptic agent of the base of polyhydric alcohol. Aqueous solution of boric acid is used as reagent 1, side products of synthesis of 4,4-dimethyldioxane-1,3 with high boiling point being used as reagent 2. Reaction is carried out at 140-160 C and pressure 4-6 atm in the presence of 0.05-0.1 mass % of oxalic, formic or phosphoric acid, thus produced reaction water and formaldehyde being uninterruptedly distilled. EFFECT: improves efficiency of method. 3 tbl

Description

 The invention relates to the field of basic organic synthesis, and more specifically to methods for producing boron-containing antiseptics to protect wood from rot and mold.

 It is known that boric esters of monohydric and polyhydric alcohols have an active biological effect against wood-destroying fungi and insects, including termites, and can be used as effective antiseptics for protecting wood and cellulose. In addition, boric esters of polyhydric alcohols are used as components of brake and cutting fluids of biocidal additives to oils and fuels, starting materials for the synthesis of other useful products.

 Boric esters of polyhydric alcohols have a whole range of valuable technical properties (high heat resistance, fairly high viscosity, transparency, the presence of biocidal and the absence of corrosive activity, etc.). However, the widespread use of these compounds in practice is hindered by their low hydrolytic stability. The absolute majority of esters, in contact with moisture, decompose into the starting components with the precipitation of boric acid.

 Known methods for producing cyclic boron esters of 3-methylbutanediol-1,3 (MBD), which is one of the components of high boiling point by-products (WFP) of the first stage of the technical process for the synthesis of isoprene from isobutylene and formaldehyde, namely, that an aqueous solution of boric acid saturated with salts metals of groups I or II of the periodic system of elements in contact with solutions of MBD in water or in organic solvents. The isolated mixture of MBD borates, soluble in both water and organic solvents, is used as an antiseptic to protect wood and cellulose (technical name Kobor [3] So, in [1] an aqueous solution of boric acid saturated with magnesium or sodium chlorides interacts with a chloroform solution of MBD at room temperature for 1-2 hours, then chloroform is distilled off from the organic layer of the reaction mixture.The yield of MBD borates is 31.2% based on the loaded diol.

Closest to the technical nature of the proposed is a method for producing [3] a mixture of cyclic ethers of MBD (Kobor). According to the prototype, Kobor is obtained by the interaction of MBD or the so-called a diol fraction isolated by distillation from the general fraction of the runway with an aqueous solution of boric acid or a mother liquor for the production of boric acid containing about 1.9-2.1% B ₂ O ₂ saturated with 20% MgSO ₄ and acidified with 0.5% sulfuric acid at room temperature. The reaction mixture is allowed to settle, then it is separated into aqueous and organic phases. The upper organic phase is defended for another day, and then filtered off from the precipitated magnesium sulfate and used as an antiseptic.

 The method of obtaining a boron-containing Kobor actiseptic according to the prototype is distinguished by the complexity of the technological design, low productivity of the equipment, the need for high alloy steels due to the corrosive environment and low yield of the target product. In addition, a distinctive feature of the resulting antiseptic is the ease of its hydrolytic decomposition under the influence of even small amounts of water with the precipitation of crystalline boric acid, which significantly limits its technical use.

 In order to increase the antiseptic properties and at the same time increase the resistance of the boron-containing antiseptic to hydrolysis, it is proposed to synthesize it as follows.

 Raw materials high-boiling by-products (WFP) of the synthesis of 4,4-dimethyldioxane-1,3 (I stage of the isoprene production process), which are a difficult to separate mixture of oxygen-containing compounds of different molecular weights belonging to different classes of organic substances derived from 1,3-dioxane, 5 , 6-dihydropyran, symmetric and asymmetric formals, ethers, etc. [3] In the conditions of industrial synthesis at steady state, the runway fraction contains, by weight, 3-methylbutanediol-1.3 0.5; 4,4-dimethyl-5-hydroxymethyldioxane-1.3 6.3-12.7; 4,4-dimethyl-5-hydroxyethyl dioxane-1,3 23.5-45.0; 4-hydroxyisopropyl dioxane-1.3 3.0-4.5; the amount of unidentified "heavy" products (mainly formalin dioxane alcohols) 67.2-37.8.

The process of obtaining water-soluble borates of polyhydric alcohols is as follows. An aqueous emulsion of the entire runway fraction (without preliminary processing) in an autoclave (or a distillation column cube operating under overpressure) is reacted with boric acid, taken in a mass ratio to the runway of 0.16-0.20, in the presence of 0, 05-0.10 wt. oxalic, formic, or phosphoric acids. The mixture was heated to 140-160 ^{° C} and at this temperature and a pressure of 4-6 atm distilled released during the reaction of formaldehyde and water.

As a result of carrying out the reaction under the indicated conditions, a mixture of polyhydric alcohols boronates with high hydrolytic stability and solubility in water is formed, which is not obvious for reactions of boric acid with runway. The structure of the obtained glycol and triol esters was confirmed by NMR spectroscopy (according to B ¹¹ ). The output of airs up to 85% on loaded runways.

 The obtained water-soluble boron esters based on the first-stage runway synthesis of isoprene from isobutylene and formaldehyde have an effective antiseptic and insecticidal effect to protect wood and varnish coatings from wood-destroying fungi and termites. The spectrum of action of the obtained actiseptic covers a wide mass of species of molds dangerous for wood and other natural materials, for example, coniophora cerebella, aspergillus, penicillium, paecilomyces, scopulariopsis. In addition to the antifungal properties, this drug has a pronounced bactericidal activity, which allows it to be used as a biocidal component of a number of technical compositions, for example, cutting fluids, disinfectants, etc. It has been established that the resulting preparation (10-12% aqueous solution) inhibits the activity of a whole group of bacterial cultures: pseudomonos, desulfobrio, eschperichia, achromobacter, acrobacter, etc. The drug is also a fairly effective insecticide, in particular, has a powerful anti-thermite ystviem. In all these indicators, as well as in its manufacturability, the resulting preparation is superior to the Kobor antiseptic. It is sufficient to indicate that on samples of wood impregnated when immersed in a 4-6% Kobor aqueous solution, a white coating of boric acid crystals appears during the drying process, while on samples impregnated with an aqueous solution of the proposed preparation, a coating of boric acid does not appears for an indefinitely long period.

 An experimental batch of runway water-soluble boron ethers was obtained at one of the chemical industry plants, which proved the possibility of industrial production of this product.

PRI me R 1. In an autoclave with a capacity of 1000 ml, equipped with a stirrer and electric heating, load a mixture containing 200 g of the runway of the following composition, wt. 3-methylbutanediol-1.3 0.5; 4,4-dimethyl-5-hydroxymethyldioxane-1.3 8.5; 4-methyl-4-hydroxyethyl dioxane-1.3 26.7; 4-hydroxyisopropyl dioxane-1,3 4,5; the amount of unidentified "heavy" products is the rest, 500 g of water, 35 g (6.5%) of boric acid (boric acid / VPP 0.175) and 0.4 g (0.055%) of oxalic acid. They include a stirring device, a nitrogen pressurized to 3 atm and the autoclave is heated from 25 to ^{160 °} C (pressure at this increased to 6 psig). The reaction mixture was kept at 160 ^{° C} for 20 min. An aqueous solution of formaldehyde is then distilled off over a water-cooled refrigerator for 25 minutes. The distilled solution is collected in a trap. After the pressure in the autoclave drops to atmospheric, the selection is stopped, the reaction mixture was cooled to 90-95 ^{° C} and discharged through the lower fitting dark red viscous liquid, representing a mixture of borate esters of polyhydric alcohols containing by analysis 4.14% boron.

The material balance of experience is as follows:
Uploaded, g: Fractions of runway 200 Water 500 N ₃ VO ₃ 35 (COOH) ₂ x2H ₂ O 0.4 Total 735.4
Unloaded, g:
Cube: Boric esters 164.7 incl. water 20 CH ₂ About 2.1
Shoulder strap: water layer 517.3 incl. CH ₂ O 34.7 N ₃ VO ₃ 1.4 Amount org.-in-9.6 organ.layer 36.0 incl. water 5.5 CH ₂ O 0.4 Total 718
Loss: 17 g (2.3% of load)
Thus, the yield of boric acid esters is 83.3% per loaded runway, the formaldehyde yield of 18 wt.

Signals at 0.2 ppm are observed in the ¹ H NMR spectrum of polyhydric alcohols isolated from the reaction of boron esters. and 0.35 ppm in a stronger field compared to boric acid. These signals correspond to the signals of borates I and II obtained by counter synthesis from 3-methylpentantriol-1,3,5 and boric acid. When the selected mixture of boron ethers is hydrolyzed, these signals decrease, and the boric acid signal (6 ppm) increases.

C

O

OH
(I) (II) Молекулярная масса полученных борных эфиров многоатомных спиртов равна 370-380.C

C

O

OH
(I) (II) The molecular weight of the resulting boric esters of polyhydric alcohols is 370-380.

 Elemental composition, wt.

1. Sample of boron esters of polyhydric alcohols: C 56.2 N 10.3 V 3.5 O 30.0
2. Borate II (calculated) C 51.7 N 8.61 V 5.26 O 34.4 Density of the mixture of boron esters of polyhydric alcohols: d $\genfrac{}{}{0ex}{}{\text{20}}{\text{4}}$ 1.146-1.147 g / cm ³ .

Refractive index: n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.720-1.4723.

 The fungistatic and fungicidal activity of the isolated mixture of boric esters of polyhydric alcohols was studied by serial dilution in liquid wort; nutritional value by serial dilution in distilled water. A mixture of mushrooms according to GOST 9.048-75 was used as test cultures. Observation was continued for 20 days.

 The results obtained (Table 1) show that boric esters of polyhydric alcohols have fungistatic activity at a 1:20 dilution. In distilled water, they inhibit the growth of fungi in breeding up to 1:80. In large dilutions (1: 160 and 1: 320), they do not affect the growth rate of fungi compared to the control, i.e. not used by mushrooms as a food source.

PRI me R 2. The experiment is carried out analogously to example 1, however, while the temperature and pressure in the autoclave is maintained in the region of 140 ^about C and 4 MPa. The mass ratio of boric acid / runway is 0.16, the concentration of oxalic acid is 0.110 wt. The mixture of boric acid esters of polyhydric alcohols contains, according to the analysis, 3.54% of boron.

The material balance of experience is as follows:
Uploaded, g: Runway fractions 200 Water 500 N ₃ VO ₃ 32 (COOH) ₂ x2H ₂ O 0.4 Total 732.4
Unloaded, g:
Cube: Boric esters 160.5 incl. water 18 CH ₂ O 2.0
Shoulder strap: water layer 525.3 incl. CH ₂ O 34.7 N ₃ VO ₃ 1.2 Amount org.-in 8.6 organ.layer 36.0 incl. water 5.0 CH ₂ O 0.3 Total 721.8
Loss: 10.6 g (1.5% of load)
Thus, the yield of boric acid esters is 80.3% per loaded runway, the formaldehyde yield of 18.5 wt.

PRI me R 3. The experiment is carried out analogously to example 1, however, while the temperature and pressure in the autoclave is maintained in the region of 150 ^about C and 5 MPa. The mass ratio of boric acid to runway is 0.16, the concentration of phosphoric acid is 0.08 wt. The mixture of boric acid esters of polyhydric alcohols contains 3.74% boron according to the analysis. The material balance of experience is as follows:
Uploaded, g: Fractions of runway 200 Water 500 N ₃ VO ₃ 35 (COOH) ₂ x ₂ N ₂ O 0.6 Total 732.6
Unloaded, g:
Cube: Boric esters 170.0 incl. water 23 CH ₂ O 2.6
Shoulder strap: water layer 521.8 incl. CH ₂ O 31.9 N ₃ VO ₃ 1.8 Amount org.-in 5.7 organ.layer 28.0 incl. water 3.0 CH ₂ O 0.1 Total 719.8
Loss: 12.8 g (1.75% of the load)
Thus, the yield of boric acid esters is 85.0% per loaded runway, the formaldehyde yield of 17.3 wt.

PRI me R 4. The experiment is carried out analogously to example 1, however, the temperature and pressure in the autoclave is maintained at a level of 160 ^about C and 6 MPa. The mass ratio of acid to runway is 0.20, the concentration of phosphoric acid is 0.10 wt. The mixture of polyhydric alcohols boric acid esters contains 4.04% boron according to the analysis.

The material balance of experience is as follows:
Uploaded, g: Runway fractions 200 Water 500 N ₃ VO ₃ 40 (COOH) ₂ x2H ₂ O 0.74 Total 740.74
Unloaded, g:
Cube: Boric esters 168.2 incl. water 25 CH ₂ O 2,8
Shoulder strap: water layer 517.0 incl. CH ₂ O 35.4 N ₃ BO ₃ 1.3 Amount org.-in 7.4 organ.layer 38.9 incl. water 3.4 CH ₂ O 0.5 Total 724.1
Loss: 16.6 g (2.24% of load)
Thus, the yield of boric acid esters is 84.1% per loaded runway, the formaldehyde yield is 19.3 wt.

PRI me R 5. The experiment is carried out analogously to example 1, however, the temperature and pressure in the autoclave is maintained within 160 ^about C and 6 MPa. The mass ratio of boric acid to runway is 0.20, the concentration of formic acid is 0.08 wt. The mixture of boric acid esters of polyhydric alcohols contains, according to the analysis, 3.96% of boron.

The material balance of experience is as follows:
Uploaded, g: Runway fractions 200 Water 500 N ₃ VO ₃ 40 (COOH) ₂ x2H ₂ O 0.4 Total 740.4
Unloaded, g:
Cube: Boric esters 164.6 incl. water 23.8 CH ₂ O 1.8
Shoulder strap: water layer 521.5 including CH ₂ O 67.8 N ₃ BO ₃ 1.4 Amount org.-in 9.2 organ.layer 40.1 including water 5.3 CH ₂ About 0.8 Total 726.2
Loss: 14.2 g (1.95% of charge).

 Thus, the yield of boric acid esters is 82.3% per loaded runway, the formaldehyde yield of 20.0 wt.

 The isolated mixture of boron esters of polyhydric alcohols was tested for toxicity to the wood-destroying caniophora cerebella fungus according to GOST 16721-71. The results are shown in table.2.

 As a result of the tests, it was found that the studied mixture has toxic effects in relation to wood-destroying fungi and protects the wood at the minimum of their tested absorption (dilution by 6 times). The weight loss of the samples observed in these studies occurs due to the partial leaching of the antiseptic from wood.

PRI me R 6. The experiment is carried out analogously to example 1, however, the temperature and pressure in the autoclave is maintained at a level of 160 ^about C and 6 MPa. The mass ratio of boric acid to runway is 0.20, the concentration of formic acid is 0.10 wt. A mixture of boric acid esters of polyhydric alcohols containing, according to the analysis, 4.03% boron.

The material balance of experience is as follows:
Uploaded, g: Fractions of runway 200 Water 500 N ₃ VO ₃ 40 (COOH) ₂ x ₂ N ₂ O 0.5 Total 740.5
Unloaded, g:
Cube: Boric esters 185.7 including water 24.7 CH ₂ O 2.0
Shoulder strap: water layer 522.5 including CH ₂ O 38.9 N ₃ BO ₃ 1.3 Total organic layer 8.8 organic layer 42.0 including water 5.1 CH ₂ About 0.4 Total: 730.2
Loss: 10.3 g (1.38% of the load).

 Thus, the yield of boric acid esters is 82.9% per loaded runway, the formaldehyde yield of 20.65 wt.

 The main results of the experiments are summarized in table 3.

Claims (1)

METHOD FOR PRODUCING AN ANTISEPTIC FOR PROTECTION OF WOOD by the interaction of an aqueous solution of boric acid with polyhydric alcohol, characterized in that high-boiling by-products of the synthesis of 4,4-dimethyldioxane-1,3 are used as a source of polyhydric alcohol and the process is carried out at 140 - 160 ^o С and 4 - 6 atm in the presence of 0.05-0.10 wt.% Oxalic, formic or phosphoric acid with continuous distillation of the reaction water and formaldehyde.

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