RU2492188C1 - Anti-agglomerator for separating synthetic rubber - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to anti-agglomerators which eliminate stickiness of rubber crumbs after the water degassing step when producing synthetic rubber by solution polymerisation during separation thereof from hydrocarbon solvents. The anti-agglomerator is a 20-40% solution in base mineral and synthetic oils without additives of a mixture of calcium salts of alkylbenzene sulphonic acids with the length of the hydrocarbon chain of alkyl substitutes ranging from C₁₂ to C₂₆ and overall base number ranging from 20 to 390 mg KOH/g.

EFFECT: high alkalinity of the aqueous medium at the degassing step, longer time between repairs of rubber drying equipment, low material consumption.

1 cl, 1 tbl, 11 ex

Description

The invention relates to a technology for producing synthetic mortars of synthetic rubbers, in particular to processes for their isolation from hydrocarbon solvents, and more specifically, to anti-agglomerators that ensure the adhesion of crumb rubber after the stage of water degassing, and can be used in the petrochemical industry.

Known antiagglomerator for the allocation of synthetic rubber from a hydrocarbon solution by the method of water degassing, which is used as a potassium salt of a copolymer of vinyl ester of cyclohexanecarboxylic acid with maleic anhydride (ed. Certificate. RF 825544, class C08C 2/06, publ. 1981).

The disadvantage of this anti-agglomerator is its high dosage - up to 20 kg per 1 ton of rubber. The poor solubility of the potassium salt of the cyclohexanecarboxylic acid vinyl ester copolymer with maleic anhydride in water makes it necessary to use an anti-agglomerator in hydrocarbon solvents, which increases the fire hazard of production.

Known antiagglomerator for the allocation of synthetic rubber from hydrocarbon solutions based on a suspension of calcium stearate in water obtained by the interaction of a dilute solution of potassium alkali with a stoichiometric amount of stearic acid for the saponification reaction by preheating the alkali solution to 70-100 ° C, followed by circulation of the resulting potassium stearate solution with a stoichiometric amount of calcium chloride (Kirpichnikov P.A., Bresnev V.V., Popova L.M. water industry of synthetic rubber L .: Chemistry, 1986, p.136). The use of the specified anti-agglomerator effectively prevents the adhesion of synthetic rubber crumbs, ensures its easy extraction from water after water degassing and its transportation to the drying stage. However, calcium stearate obtained in the form of a suspension in this way has insufficient dispersion and aggregative stability, which requires strong alkalization to pH 10-12 to maintain it. This leads to an increase in the consumption of calcium stearate, an increase in the alkalinity of water effluents, an uneven distribution of the anti-agglomerator in the rubber crumb, and a change in the Mooney rubber viscosity on drying machines.

A prototype of the present invention is an anti-agglomerator for isolating synthetic rubber from hydrocarbon solutions based on a suspension of calcium stearate, obtained by isolating in the form of an aqueous highly alkaline suspension a sequential interaction of stearic acid with solutions of alkali and calcium chloride. In this case, stearic acid is preliminarily fed into an aqueous medium with a temperature of 55-65 ° C, and the product of the interaction of stearic acid with alkali is heated to 75-85 ° C and diluted 1.5-2.5 times (RU 2190592, class C0751 / 41, publ. 10.10.2002). The resulting suspension of the anti-agglomerator has a particle size of 100-500 μm, which allows to obtain a stable crumb of synthetic rubber in water due to the uniform distribution of the anti-agglomerator and to reduce the possibility of changing the Mooney rubber viscosity on drying machines.

The disadvantage of this suspension of the anti-agglomerator is the need for auxiliary multi-stage operations for its synthesis immediately before use, the high consumption rate is up to 5 kg of the suspension of the anti-agglomerator per 1 ton of rubber, due to the partial decomposition of the anti-agglomerator according to the prototype with acidic waters formed when rubber is released due to the deactivation of the residual polymerization catalyst, deterioration of the “Ash Content” indicator, as well as high alkalinity of water flows.

The technical result of the present invention is:

- reducing the high alkalinity of the aquatic environment at the stage of degassing, necessary to maintain the aggregate stability of the anti-agglomerator of the prototype and reducing the cost of neutralizing alkaline effluents;

- the increase in overhaul runs of equipment for drying rubbers by eliminating the clogging of dies on drying machines (expanders) with decomposition products of an anti-agglomerator (calcium stearate) according to the prototype;

- decrease in expenditure rates of raw materials.

To achieve the specified technical result, a 20-40% solution in mineral or synthetic base oils without additives of a mixture of calcium salts of alkylbenzenesulfonic acids with a hydrocarbon chain length of alkyl substituents from C ₁₂ to C ₂₆ and a total alkaline solution in the range from 20 to 400 mg is proposed as an anti-agglomerator KOH / g

A distinctive feature of the anti-agglomerator according to the invention from the anti-agglomerator according to the prototype is the replacement of the dispersed phase of calcium stearate in the form of a suspension in highly alkalized water according to the prototype — a 20-40% solution of alkylbenzenesulfonic acid mixtures of alkaline calcium salts in mineral or synthetic oil with a hydrocarbon chain of alkyl substituents from C ₁₂ From ₂₆ to chemically stable in aqueous media at temperatures close to the temperatures of the aqueous degassing (boiling water), which allows for lower than on the forward prototypes, alkalinity values for degassing the aqueous medium. This difference between the anti-agglomerator according to the present invention and the anti-agglomerator according to the prototype corresponds to the patentability attribute “novelty”, and the use of the proposed anti-agglomerator reduces the alkalinity of the aqueous medium during degassing of rubbers, reduces the adhesion of the crumbs at the isolation stage at equal or lower consumption rates of the anti-agglomerator than the prototype meets the requirement "Inventive step".

In addition, the uniform distribution of the aqueous emulsion of the anti-agglomerator oil solution over the surface of the rubber crumb completely eliminates the use of calcium chloride, which is necessary for preparing the working suspension of the anti-agglomerator according to the prototype, avoids excessive alkalinity of the medium necessary to maintain the aggregative and chemical stability of the anti-agglomerator, and reduces salt and alkaline effluents and eliminate the stickiness of the released rubber on the drying equipment.

The anti-agglomerator of the present invention is prepared in several stages as follows.

Example 1

1. From the fraction of C ₁₂ -C ₂₆ alkylbenzenes (AB), which is the feedstock with the following physicochemical characteristics:

- specific gravity at 20 ° C 0.87

- average molecular weight 392,

prepare a mixture of alkylbenzenesulfonic acids (ABA).

For this purpose, 100 grams of AB is placed in a three-necked flask with a capacity of 1 dm ³ , equipped with a stirrer and a thermometer, and 40 ml of Nefras P1-63 / 75 solvent are diluted at 20 ° C. Then the AB is sulfonated, for which 156 grams of oleum containing 20% SO _{3 are} added to the AB solution in Nefras P1-63 / 75 and, stirring for 5 minutes, the temperature of the mixture is kept at 35 ° C, cooling the flask in an ice bath. At the end of sulfonation of AB, 13 ml of water and 60 ml of Nefras C2-80 / 120 solvent are added to the mixture, the resulting mixture is stirred, and the acid sludge is separated from the mixture by decantation. About 210 grams of a crude solution of a mixture of alkylbenzenesulfonic acids (ABA) with an average molecular weight of ~ 480 are obtained in the organic layer.

2. The resulting crude solution of a mixture of alkylbenzenesulfonic acids was charged into a 500 cm ³ double neck flask equipped with a reflux condenser, and 4.2 grams of quicklime were added with stirring. The quicklime mixture is heated to a boiling point (~ 60 ° C) and incubated for 2 hours, after which the contents are removed from the flask and centrifuged. The solvents are removed by distillation and an ABA mixture with the following characteristics is obtained:

- content of alkylbenzenesulfonic acids 89%

- acidity (milliequivalents / g) 1.28

- viscosity at 100 ° C, cSt 55.

3. The resulting ABA mixture in an amount of 100 grams is placed in a 1-liter three-neck round-bottom flask equipped with a stirrer, reflux condenser and thermometer, diluted with 160 grams of I-20A mineral oil with a viscosity at 40 ° C of 20 cSt, and after stirring at 40 ° C within 10 minutes receive 260 grams of a 39% solution of ABA in mineral oil I-20A.

4. To the resulting solution of ABA in I-20A mineral oil containing 0.19 moles of ABA with an average molecular weight of 480, 100 ml of Nefras C2-80 / 120 solvent are added. The resulting mixture was heated to 30 ° C and 15 grams of calcium hydroxide was added to it.

5. Then the mixture is heated to boiling point (~ 67 ° С), solvents with reaction water are distilled off, gradually increasing the temperature to 160 ° С, while nitrogen is bubbled into the mixture, and after cooling it is filtered through a Buchner funnel with a diameter of 11.5 cm filled with granules diatomite. Get a solution of a mixture of calcium salts of alkylbenzenesulfonic acids transparent with a vessel thickness of 5 cm with the following characteristics:

- viscosity at 100 ° C, cSt one hundred - mass fraction of calcium alkyl sulfonates,% 40 - mass fraction of oil 60 - total alkaline number (TSP), mg KOH / g twenty - sulfate ash,%, n / a 10

Example 2

1.100 grams of the ABA mixture prepared in the first two stages of Example 1 is placed in a 1 dm ³ three-necked round-bottom flask equipped with a stirrer, reflux condenser, thermometer and capillary for supplying carbon dioxide or nitrogen, diluted with 280 grams of I-20A mineral oil with a viscosity of 40 ° C, equal to 20 cSt, and after stirring at 40 ° C for 10 minutes, 380 grams of a ~ 26% ABA solution in I-20A mineral oil is obtained. 20 ml of toluene and 40 ml of methanol containing 12.3 wt.% Water are added to the flask.

2. Then the mixture is heated to 31-34 ° C, 30 grams of calcium hydroxide is introduced into it and for 60 minutes 210 ml of carbon dioxide are bubbled into the mixture with stirring at a rate of 3.5 ml / minute, maintaining the temperature not higher than 34 ° C. After completion of the reaction, the solvents are distilled off, gradually raising the temperature to 160 ° C, while sparging nitrogen into the mixture, and after cooling, it is filtered through a 11.5 cm Buchner funnel filled with diatomite granules. Get a solution of a mixture of medium alkaline salts of calcium alkylbenzenesulfonic acids, transparent with a vessel thickness of 5 cm with the following characteristics:

- viscosity at 100 ° C, cSt one hundred - mass fraction of calcium alkyl sulfonates,% 28 - mass fraction of oil 72 - total alkaline number (TSP), mg KOH / g 140 - sulfate ash,%, n / a 19

Example 3

1. The mixture of ABA obtained in the first stage of Example 2 is diluted with 280 grams of Norman 346 ^® synthetic oil manufactured by Orgkhim, Nizhny Novgorod, RF, according to TU 0258-047-58604719-2004.

2. 150 grams of the resulting solution of a mixture of ABA in Norman 346 ^® synthetic oil is loaded into a flask, 35 ml of toluene and 40 ml of methanol containing 12.3 wt.% Water are added.

3. Then the mixture is heated to 31-34 ° C, 60 grams of calcium hydroxide are added to it and for 60 minutes 210 ml of carbon dioxide are bubbled into the mixture with stirring at a rate of 3.5 ml / minute, maintaining the temperature not higher than 34 ° C. After completion of the reaction, the solvents are distilled off, gradually raising the temperature to 160 ° C, while sparging nitrogen into the mixture, and after cooling, it is filtered through a 11.5 cm Buchner funnel filled with diatomite granules. Get a solution of a mixture of calcium salts of alkylbenzenesulfonic acids transparent with a vessel thickness of 5 cm with the following characteristics:

- viscosity at 100 ° C, cSt one hundred - mass fraction of calcium alkyl sulfonates,% 28 - mass fraction of oil Norman 346 ^® 72 - total alkaline number (TSP), mg KOH / g 290 - sulfate ash,%, n / a 37

Example 4

1. 155 grams of a 20% ABA solution in I-40A mineral oil obtained as described in the first step of Example 2 are charged into a three-necked flask, and 44 ml of toluene and 40 ml of methanol containing 12.3 wt.% Water are added.

2. Then the mixture is heated to 31-34 ° C, 70 grams of calcium hydroxide are introduced into it and for 60 minutes 210 ml of carbon dioxide are bubbled into the mixture with stirring at a rate of 3.5 ml / min, maintaining the temperature at about no higher than 34 ° C. . After completion of the reaction, the solvents are distilled off, gradually raising the temperature to 160 ° C, while sparging nitrogen into the mixture, and after cooling, it is filtered through a 11.5 cm Buchner funnel filled with diatomite granules. Get a solution of a mixture of calcium salts of alkylbenzenesulfonic acids, transparent with a vessel thickness of 5 cm with the following characteristics:

- viscosity at 100 ° C, cSt 150 - mass fraction of calcium alkyl sulfonates,% twenty - mass fraction of oil 80 - total alkaline number (TSP), mg KOH / g, n / m 390 - sulfate ash,%, n / a 47

To illustrate the advantages of the anti-agglomerator of the present invention and to obtain data on the comparative properties of the prototype, samples of the anti-agglomerators of the present invention and the prototype are prepared and tested in the process of isolating synthetic rubbers by the methods described in the following examples.

Example 5 (comparative prototype patent RU 2190592)

For anti-agglomeration of rubber crumb SKD-N, an aqueous suspension of calcium stearate is prepared according to the prototype.

To this end, in a round-bottomed two-necked flask with a capacity of 1 l, equipped with a stirrer, and a thermometer and placed in a sand bath, partially softened water in the amount of 260 ml is loaded and heated to 60 ° C. Then 10 g of stearic acid are poured into the same place, and after its uniform distribution, 5 ml of alkali, 40% potassium hydroxide solution, is loaded into the flask. After loading the alkali, the temperature was raised to 80 ° C and the mixture was stirred for 2 hours. Then another 260 ml of water are poured into the flask and 7 ml of a 35% solution of calcium chloride are added dropwise. Stir for another 0.5 hours. A thin aqueous suspension of calcium stearate is obtained in an amount of about 540 ml with an anti-agglomerator concentration in it of 12% and a pH of 11.0.

Then prepare rubber samples for anti-agglomeration. Why, out of 10 grams of SKD-N rubber crumb obtained by laboratory isolation from industrial polymerizate — 12% rubber solution in a polymerization medium — a mixture of aliphatic solvents like Nefras 80/120 (with boiling points from 80 to 120 ° C) cut into pieces (4 -5) × (4-8) mm.

Pieces of SKD-N rubber, avoiding sticking, are placed in a 150-200 ml beaker with 100 ml of demineralized water heated in a sand bath or tile with a magnetic stirrer with stirring to a temperature of 70-80 ° C without adding a suspension of calcium stearate, which is prototype anti-agglomerator.

In another 150-200 ml beaker with 100 ml of demineralized water, heated in a sand bath or a tile with a magnetic stirrer, while stirring to a temperature of 70-80 ° C, immediately before loading the rubber crumbs in the form of pieces into the water, they are introduced dropwise into the water using a microsyringe. the amount obtained, as described above, of a freshly prepared suspension of calcium stearate - anti-agglomerator according to the prototype with a concentration of 12% and a pH of 11.0.

In the absence of anti-agglomerator additives, the pieces of rubber begin to stick together as soon as they are loaded into water.

When adding an anti-agglomerator according to the prototype, the absence of adhesion for 4 hours is determined by its minimum amount necessary so that the pieces of rubber do not stick together. To this end, the number of drops of an aqueous suspension of an anti-agglomerator according to the prototype is gradually increased in a glass of water before placing pieces of rubber in it, starting from 4-5. In this example, the number of drops corresponding to the minimum amount necessary so that the SKD-N rubber pieces do not stick together is 14-15 or 0.061 grams per dry matter per 10 grams of rubber crumb, which is equivalent to 6.1 kg / ton of crumb rubber. The increase in ash content of the rubber obtained is 0.15%.

Example 6

To conduct anti-agglomeration of rubber crumbs SKD-N according to the invention, a sample of rubber SKD-N with a mass of 10 grams is prepared, as shown in Example 5. Pieces of rubber, avoiding sticking, are placed in a 150-200 ml beaker with 100 ml of demineralized water heated on sand bath or tile with a magnetic stirrer with stirring to a temperature of 70-80 ° C.

Immediately before placing the rubber pieces in heated water, a measured amount of the anti-agglomerator of the present invention is introduced dropwise with stirring with a microsyringe, using a 40% solution of the anti-agglomerator in I-20A mineral oil with OSCH = 20 mg KOH / g, obtained according to Example 1.

Gradually increasing the number of drops of the introduced anti-agglomerator, determine the minimum number of drops necessary so that the pieces of rubber do not stick together. In this example, their total volume is 0.055 ml or, on a dry matter basis, 0.02 g / 10 grams of pieces of crumb rubber SKD-N, which is equivalent to 1.98 kg of the anti-agglomerator according to the invention per ton of rubber SKD-N. The increase in the ash content of rubber is 0.05%, which is lower than when using the prototype anti-agglomerator twice.

Example 7

Prepare a rubber sample SKD-N weighing 10 grams, as shown in Example 5 and 100 ml of demineralized water, heated with stirring to 70-80 ° C, as in Example 6.

Directly before loading the rubber pieces SKD-N, using a microsyringe, 0.063 ml or 0.05 grams of the prepared 20% solution of I-40A mineral oil of the anti-agglomerator obtained according to Example 2 is introduced dropwise with stirring with a VLF equal to 390 mg KOH / g.

After introducing pieces of rubber into heated water with an anti-agglomerator, a complete absence of adhesion of pieces of rubber is observed after 4 hours of exposure. Its dosage in this example 7 is in a dry weight of 1.73 kg per ton of rubber.

Anti-agglomeration of 10 grams of SKD-N rubber pieces with a 20% solution of an anti-agglomerator in I-40A mineral oil obtained according to Example 2, in an amount of 0.08; 0.10 and 0.13 ml, or 0.063, 0.072 and 0.117 grams respectively, corresponds to the dosage of the anti-agglomerator per ton of rubber in dry weight - 1.73, 2.52, 2.88 and 4.80 kg, respectively. In all these cases, there is a complete lack of adhesion of SKD-N rubber pieces for more than 4 hours, but in the latter case, the appearance of a weak opalescence of the oil emulsion in water indicates the possibility of sedimentation. The increase in ash content of the obtained SKD-N rubber samples is 0.048, respectively; 0.55; 0.65; 0.070%.

Thus, the dosage range of the anti-agglomerator of the present invention with an VLF of 390 mg KOH / g to achieve no adhesion of SKD-N rubber pieces for at least 4 hours is from 1.73 to 4.80 kg in dry weight per a ton of rubber with the exception of sedimentation of the anti-agglomerator.

Example 8 (comparative prototype).

From 1 liter of industrial SKI-3 rubber polymerizate - a 12% solution in an isopentane-isoprene mixture containing 0.20 wt.% Antioxidant, after deactivation of the polymerization catalyst by adding 20 ml of ethyl alcohol with stirring by sparging into the polymerizate of hot steam with a temperature of 110 ° A rubber sample is isolated in an amount of about 100 grams. The resulting mass of rubber is squeezed on rollers at a temperature of 75 ± 5 ° C and dried in a thermostat at the same temperature for 24 hours. As in Example 5, cut 10 grams of pieces of rubber SKI-3 and prepare 100 ml of demineralized water, heated with stirring to 70-80 ° C.

In the heated water immediately before placing the SKI-3 pieces into it using a microsyringe, a measured amount of the anti-agglomerator suspension freshly prepared according to Example 5 is added dropwise according to the prototype with a concentration of 12%, starting from 4-5 drops, and the amount of added anti-agglomerator is determined, expressed in grams dry matter of the anti-agglomerator per 1 kg of rubber, or, also, in kg of anti-agglomerator per 1 ton of rubber, necessary so that the pieces of rubber SKI-3 at 70-80 ° C would not stick together for 4 hours.

In the absence of anti-agglomerator additives, pieces of rubber begin to stick together as soon as they are loaded into water.

The absence of adhesion for 4 hours is observed when the amount of anti-agglomerator suspension added to water according to the prototype is 12-13 drops or 0.05 grams of dry matter according to the prototype per 10 grams of rubber pieces, which is equivalent to 5 kg / ton of rubber. The increase in ash content of the rubber is 0.15%.

Examples 9, 10, 11

Prepare 10 grams of chopped pieces of rubber SKI-3 and 100 ml of demineralized water, heated with stirring to 70-80 ° C, as in Example 5. In heated water immediately before placing pieces of rubber SKI-3 using a microsyringe, dropwise with while stirring, the anti-agglomerator obtained in Example 3 is a ready-made 28% solution of a mixture of calcium salts of alkylbenzenesulfonic acids in Norman 346 ^® synthetic oil with an OSH ratio of 290 mg KOH / g. The amount of anti-agglomerator required for the complete absence of adhesion of pieces of rubber for at least 4 hours is 0.075 ml or 0.067 grams. Given the content in the oil solution of the anti-agglomerator, its consumption rate in dry weight is 2.68 kg per ton of rubber SKI-3. The increase in the ash content of rubber is 0.07%.

A similar procedure is repeated with anti-agglomeration, 10 grams of SKI-3 rubber pieces, added to hot water before adding 0.10 and 0.13 ml, or 0.06 and 0.08 grams of anti-agglomerator, respectively:

- 28% solution of the anti-agglomerator in I-20A mineral oil with an OShch = 140 mg KOH / g, obtained according to Example 2 (in Table 1, the data of Example 10) and

- 20% solution of anti-agglomerator in mineral oil I-40A, obtained according to Example 4, with an indicator OSHCH = 390 mg KOH / g - (in table 1 the data of Example 11).

Within 4 hours, a complete absence of adhesion of the rubber pieces is observed. The increase in ash is respectively 0.06 and 0.05 wt.%.

The table shows the comparative properties proposed in the invention of the anti-agglomerator in comparison with the prototype.

These tables show that the anti-agglomerator proposed by the present invention for isolating synthetic rubber, in contrast to the prototype anti-agglomerator, does not require a special increase in the alkalinity of the medium to pH 11-12 to maintain the aggregative and chemical stability of the anti-agglomerator solution in the degasser, which reduces the amount of salted water effluents , reduces the ash content of rubber and reduces the consumption of anti-agglomerator by 1 ton of rubber.

Claims (1)

An anti-agglomerator for isolating synthetic rubbers of solution polymerization, which is a 20-40% solution in base mineral and synthetic oils without additives of a mixture of calcium salts of alkylbenzenesulfonic acids with a length of the hydrocarbon chain of alkyl substituents from C ₁₂ to C ₂₆ and a total alkaline number in the range from 20 to 390 mg KOH / g