RU2531611C2 - Method of producing preparation for treating fruit and vegetable products - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of a preparation for treating agricultural products. The method of producing a preparation for treating fruit and vegetable products includes mixing liquid 1-methycyclopropene with a mixture consisting of α-cyclodextrin 0.1-80 wt %, cucurbituril 0.1-80 wt % and water 10-50 wt %, at 2-10°C for 2-4 hours, until complete absorption of 1-methycyclopropene. The obtained mass is then dried at 20-80°C to obtain a dry residue.

EFFECT: invention is intended to protect fruit and vegetable products from physiological and viral diseases, prolongs shelf life and improves the quality of fruit and vegetable products.

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Description

The invention relates to a technology for producing a preparation for processing agricultural crops in order to protect against physiological and viral diseases, which helps to increase shelf life and improve the quality of fruit and vegetable crops. In particular, the invention relates to a technology for producing preparations based on 1-methylcyclopropene (1-MCP), which have properties that block the effect of the "aging gas" - ethylene on maturation receptors.

In view of the extreme instability and high reactivity, numerous binding options have been proposed for various sorption substances and methods that allow 1-methylcyclopropene to be stored, transported and used for a long time as a preparation for processing vegetables and fruits in the post-harvest season.

So, it is known that as such sorption - encapsulating agents, the use of various macrocyclic organic compounds, framework silicates and mineral substances of various structures is proposed. In addition, a number of studies suggest the use of organic solvents and their emulsions as substances that impede and retard the oxidation and polymerization of 1-methylcyclopropene, thereby increasing the shelf life.

A known method of producing the drug by sorption of MCP cyclodextrins. The method is carried out by passing gaseous 1-methylcyclopropene through an aqueous solution containing pure α-cyclodextrin, followed by filtration and drying of the wet preparation. This method allows to obtain drugs with a content of MCP up to 5% wt. (see US patent US6953540).

The main disadvantage of this method is that when gaseous 1-methylcyclopropene is passed through an aqueous solution of α-cyclodextrin, unavoidable losses occur due to the difference in the speed of gas passage (bubbling) and its sorption. In addition, at reduced gas flow rates, unavoidable pressure drops are possible due to clogging of the bubble holes due to the abundant formation of a precipitate, a complex compound of 1-MCP and α-cyclodextrin, which greatly affects the operation of the existing installation and may be the result of its depressurization, impurities and for the synthesis of foreign substances. It should also be noted that the use of an aqueous solution of α-cyclodextrin is very limited in time due to the effects of bacteria on it and, as a result, the loss of its sorption capabilities and the loss of the relatively expensive component of this synthesis.

A known method for producing a powder preparation by contacting gaseous 1-MCP with organic and inorganic solid porous substances, which were used cyclodextrins, starch, crown ethers (15-crown-5 and dibenzo-18-crown-6), cryptands (Kryptofix® 221 and Kryptofix® 222), PEG-13 polyethylene glycol, acetamide, urotropin, modified - CD (ethoxylated n = 6), diatomite, coals of various grades, zeolites (see Patent RU2267272).

The main disadvantages of the proposed technology are laborious operations for mixing the solid phase in a gaseous medium, maintaining the necessary pressure, relatively low absorption rates and low masses. the percentage of 1-methylcyclopropene in the sorbents.

The closest in technical essence and the achieved result to the proposed method is a method for producing the drug by contacting gaseous 1-MCP with a mixture containing α-cyclodextrin and an aqueous buffer solution (see Patent US6017849).

The inventors do not indicate the percentage of absorbed 1-methylcyclopropene, on the basis of which it is difficult to judge the advantages of this technology.

The main disadvantages of this method, due to the lack of additional stages of gas purification, should include the ingress of various impurities of the C4 fraction, as well as metal chloride, which is one of the starting compounds in the synthesis of producing 1-methylcyclopropene. In addition, as in the previously described options, the disadvantages include the difficulties associated with the bubbling and swings of the system.

The objective of the invention is to provide a method for producing a preparation with a high content of 1-methylcyclopropene, contributing to the most complete and rapid release of 1-methylcyclopropene in the gas phase during processing of fruits and vegetables.

The problem is solved by creating a method for producing a preparation with a high content of 1-methylcyclopropene for processing fruit and vegetable products by mixing liquid 1-methylcyclopropene with a mixture of α-cyclodextrin and water, characterized, according to the invention, in that liquid 1-methylcyclopropene is mixed with a mixture consisting of α β-cyclodextrin from 0.1 to 80 wt.%, cucurbituril from 0.1 to 80 wt.% and water from 10 to 50 wt.%, at a temperature of 2 to 10 ° C for 2-4 hours, until complete sorption 1- methylcyclopropene, then the resulting mass is dried at a pace a temperature of from 20 to 80 ° C to obtain a dry residue.

The technical result is to reduce the loss of 1-methylcyclopropene associated with:

- with entrainment of gas when passing it through a liquid or solid layer of sorbents;

- with less time required to dry the complex, due to the lower moisture content;

- with less loss of relatively expensive cucurbituril and α-cyclodextrin due to the absence of filtration stages.

Since the presence of water polarizes the outer surface of the cyclodextrin molecule due to OH groups, as a result of which the inner cavity acquires more pronounced hydrophobic properties, which allows complex inclusions to form with other host-guest organic compounds. Taking into account that the inner diameter of the torus cavity of α-cyclodextrin is 5.2 Ǻ, it determines its choice from the class of cyclodicstrins. The use of cucurbituril, in view of the similar size of the internal diameter of the torus cavity, equal to 5.5 также, also contributes to the enhancement of the encapsulation effect of 1-methylcyclopropene.

The proposed method avoids all the disadvantages of the previously listed methods.

The production method is as follows.

Obtaining 1-MCP is carried out according to a known method: to 10 grams of sodium amide in 50 ml of anhydrous tetrahydrofuran in a stream of nitrogen, a solution containing 23.1 grams of metal chloride in 50 ml of anhydrous tetrahydrofuran is added. After which the mixture is slowly heated to a boil. The resulting gas is passed through an aqueous solution of sulfuric acid 1 N, after which the gas is condensed in a “trap” with dry ice (see "Synthesis of 1-Methylcyclopropene" F. Fisher, DE Applequist, Noyes Chemical Laboratory. University of Illinois Urbana, Illinois 61803 February 24, 1965).

Example 1

Obtained by the above method, liquid 1-MCP in an amount of 8.2 grams is thoroughly mixed at a temperature of 2-4 ° C for 4 hours until complete visual absorption with a mixture consisting of 110 grams of cucurbituril, 120 grams of α-cyclodextrin and 72 grams water. The resulting mixture was dried at 60 ° C to a constant weight of 239.7 grams. The amount of sorbed 1-MCP is determined by gas chromatography (GC), pre-dissolving a portion of the mixture in an alkaline solution and analyzing the gas phase released.

According to GC, the content of 1-MCP in the resulting mixture was 3.1 wt.%.

The preparation of 1-MCP was carried out according to the method consisting in the following: 12 grams of sodium amide in 20 ml of hydrocarbon fraction of C14-17 paraffins are loaded into a 150-ml 3-neck flask equipped with a magnetic stirrer and a device for passing a nitrogen current through the system , the mixture is heated to a temperature of 80 ° C, and with thorough stirring using a perilstatic pump and passing a stream of nitrogen through the mixture, 27.2 grams of metal chloride in 15 ml of hydrocarbon fraction of C14-17 paraffins are added. The gas stream is directed through an aqueous solution of sulfuric acid 1 N and the gas is condensed in a “trap” with dry ice (see “A Simple Synthesis of Cyclopropene” GL Closs and KD Kranta, Department of Chemistry, The University of Chicago (October 26, 1965) .

Example 2

Obtained by the above methodology, liquid 1-MCP in the amount of 8.9 grams is mixed with a mixture of 10 grams of cucurbituril, 220 grams of α-cyclodextrin and 100 grams of water, after thorough mixing at a temperature of 2-4 ° C for 4 hours, the mixture is dried at 60 ° C to a constant weight of 241.2 grams.

The amount of sorbed 1-MCP is determined by gas chromatography (GC), the content of 1-MCP in the mixture was 2.8 wt.%.

Example 3

The synthesis was carried out by analogy with example 2, ethylbenzene was used as a solvent. The yield of liquid 1-MCP was 9.1 grams. Sorption of liquid 1-MCP was carried out at a temperature of 2-4 ° C with thorough mixing with a mixture consisting of 200 grams of cucurbituril, 30 grams of α-cyclodextrin and 30 grams of water. The result was a powder weighing 238.5 grams with a 1-MCP content of 3.4%.

Example 4

The synthesis was carried out by analogy with example 2, the sorption of liquid 1-MCP obtained in quantities of 8.5 grams was carried out by mixing with a mixture of moistened α-cyclodextrin in an amount of 230 grams and water in an amount of 100 grams.

The content of 1-MCP 2.3% in the final powder.

Example 5

The synthesis was carried out by analogy with example 2, the sorption of liquid 1-MCP obtained in amounts of 9.1 grams was carried out by mixing with a mixture of moistened cucurbituril in an amount of 230 grams and water in an amount of 40 grams.

The content of 1-MCP according to GC analysis is 3.8% in the final powder.

Claims (1)

A method of obtaining a preparation for processing fruits and vegetables by mixing 1-methylcyclopropene with a mixture of α-cyclodextrin and water, characterized in that they mix liquid 1-methylcyclopropene with a mixture consisting of α-cyclodextrin from 0.1 to 80 wt.%, Cucurbituril from 0.1 to 80 wt.% And water from 10 to 50 wt.%, At a temperature of 2 to 4 ° C for 2-4 hours, until complete absorption of 1-methylcyclopropene, then the resulting mass is dried at a temperature of from 20 to 80 ° C to obtain a dry residue.