PL244776B1 - Method of producing TDAE petroleum plasticizer intended for rubber and rubber - Google Patents

Abstract

The subject of the application is a method for producing TDAE petroleum plasticizer intended for rubber and rubber. According to the invention, it consists in treating a vacuum distillate from petroleum with paraffin-sulphur-asphalt, with a boiling range of fraction 5 ÷ 95% 395 ÷ 590°C and a refractive index n<sub >D</sub>⁷⁰ below 1.528, refining with furfurol at a distillate:furfurol mass ratio of 1:2.7 ÷ 3.9 and extraction temperatures: bottom of the column 82 ÷ 101°C, top of the column 109 ÷ 126°C, then the obtained extract, after the separation of furfurol, is re-refined with a mixture of furfurol and co-solvent formamide with a content of 5% to 10% m/m, based on the mass of the solvent mixture, at the mass ratio extract: (mixture of furfurol with formamide ) of 1:1.0 ÷ 2.0 and extraction temperature: bottom of the column 75 ÷ 102°C, top of the column 105 ÷ 132°C and a raffinate is obtained which, after distilling off the solvents, meets the requirements of the TDAE plasticizer.

Description

Description of the invention

The subject of the invention is a method for producing TDAE petroleum plasticizer intended for rubber and rubber.

Aromatic petroleum plasticizers are characterized by good compatibility with rubbers, especially with synthetic styrene-butadiene rubber SBR and natural rubber NR, commonly used in the production of car tires.

These plasticizers are introduced as an addition to SBR rubber at the stage of its production and as a component in the process of producing rubber mixtures.

Highly aromatic plasticizers, due to the high content of polycyclic aromatic hydrocarbons PAH (Polycyclic Aromatic Hydrocarbons) with carcinogenic effects, are included in category 2 of carcinogenicity. Therefore, an important problem is to reduce the content of carcinogenic compounds in them. To assess the level of carcinogenic compounds, the IP 346 method for determining polycyclic aromatic compounds PCA (Polycyclic Aromatic Compounds) extracted with dimethyl sulfoxide is widely used. A safe level is considered to be below 3% PCA. The European Union additionally requires (Regulation 1907/2006 EU) the determination of eight individual polycyclic aromatic hydrocarbons (PAHs). The content below 10 ppm of the sum of eight PAHs, including below 1 ppm of benzo(a)pyrene, was considered safe.

Highly aromatic petroleum plasticizers DAE (Distillate Aromatic Extract) are produced based on aromatic extracts obtained as a by-product during the production of base oils using the solvent method. Aromatic extracts from selective refining with furfural or N-methylpyrrolidone, and in older processes with cresol or phenol, of vacuum distillates of crude oil are used for this purpose. Aromatic extracts from selective refining of deasphalted vacuum residue of crude oil are also used.

DAE plasticizers are characterized by good processing and use properties, but they contain carcinogenic hydrocarbons (PAH) in amounts several times higher than the limit values adopted for plasticizers considered non-carcinogenic. Methods for reducing the content of PAH hydrocarbons in aromatic extracts from selective refining of vacuum distillates and deasphalted vacuum crude oil residues consist in separating them from the aromatic extract by selective re-refining or their hydrogenation in the catalytic hydrorefining process. Mixed processes with selective preliminary refining combined with hydrorefining are also used. These processes enable the production of aromatic plasticizers with reduced levels of PAH hydrocarbons.

The aromatic plasticizer TDAE (Treated Distillate Aromatic Extract) meets the requirements for non-carcinogenic plasticizers in terms of the content of aromatic compounds PCA and PAH and due to the ban on the use of the highly aromatic DAE plasticizer in the European Union from January 1, 2010, it is its most important substitute in the production of rubbers and car tires.

Aromatic plasticizers such as TDAE, RAE, TRAE have similar applications, and the differences in physicochemical properties result from the fact that they are obtained by producing them from different vacuum fractions or deasphalted vacuum residue. An example of these differences are the viscosity requirements for these aromatic petroleum plasticizers. Their viscosity range at 100°C is different and may be in the range:

- for TDAE plasticizer from 15 to 25 mm ² /s

- for TRAE plasticizer from 28 to 50 mm ² /s

- for plasticizer RAE from 45 to 75 mm ² /s.

A characteristic feature of these plasticizers is that they meet the requirements of the REACH regulation (Regulation 1907/2006 EU), which was previously confirmed by the content of polycyclic aromatic hydrocarbons WZA (DMSO extract) below 3.0 m/m according to the IP 346 standard, and currently the content of 8 polycyclic aromatic hydrocarbons ( PAHs) below 10 mg/kg and below 1 mg/kg of benzo(a)pyrene. Examples of selective refining of aromatic extract from a vacuum distillate in an extraction column using furfural as an extractant are presented in patent description DE 3930422. Selective refining with two-stage separation of raffinate from a solution of aromatic extract in furfural by lowering the temperature is presented in patent description EP 839891. Examples are given in this description refining with furfural the aromatic extract obtained from the vacuum distillate and the deasphalted vacuum residue of crude oil.

Mixed processes of selective refining of an aromatic extract from a vacuum distillate and subsequent refining with hydrogen are disclosed in the patent descriptions: DE 2343238 and EP 1106673. Furfural is used as an extractant in the process according to application DE 2343238, and according to application EP 1106673: N-methylpyrrolidone.

The hydrotreating process leading to the hydrogenation of polycyclic aromatic hydrocarbons in a mixture of aromatic extract from vacuum distillate with vacuum distillate of crude oil using Ni-Mo/AbO3 and Ni-Co-Mo/AbO3 catalysts is presented in patent EP 1260569.

The patent descriptions present extracts with various properties. For the aromatic extract from selective refining of vacuum distillate, the PCA content is from 16% according to patent description EP 839891, and up to 29% according to patent description EP 1106673. For the extract from selective refining of deasphalted vacuum residue according to patent description EP 839891, the PCA content is 5.5% .

The examples discussed above do not specify the type of crude oil and the characteristics of the vacuum distillates from which aromatic extracts used to produce TDAE plasticizers are produced.

The patent description PL-207051 presents the preparation of a TDAE plasticizer as a result of selective refining of an aromatic extract from a vacuum distillate in an extraction column using furfural as an extractant; a raffinate with a low level of PAHs (Polycyclic Aromatic Hydrocarbons) was obtained, which is composed in the appropriate proportion with the extract obtained in the deasphalt refining process (DAO). Patent description PL224956 concerns an improvement of the method for producing a petroleum plasticizer for rubber and rubber according to patent PL207051, consisting in extending the darkened fraction of the raw material subject to propane deasphalting and using the obtained extract as another ingredient to produce the plasticizer.

Patent descriptions PL-207052 and PL-207056 present the preparation of a TDAE plasticizer as a result of selective refining from a vacuum distillate in an extraction column using furfural and then re-refining the obtained raffinate with a low level of PAHs with furfural, obtaining the desired aromatic extract, which is composed in the appropriate proportion. with the extract obtained in the deasphalt refining process (DAO) or subjected to vacuum distillation into fractions and composing the obtained fractions to achieve the required quality of petroleum plasticizer for rubber and rubber.

Patent PL 208531 concerns the production of an aromatic plasticizer containing less than 3% PCA. The method of producing the plasticizer consists in exposing the extract to the action of a polar solvent, dimethyl sulfoxide, in a weight ratio of polar solvent to extract ranging from (2.0-4.0):1, at a temperature between 30°C and 120°C, and using the obtained raffinate as an aromatic plasticizer.

Patent application WO2011098096 (A1) relates to the production of process oils from the refining of mineral oils with improved properties, this method comprising the extraction of the RAE (Residual Aromatic Extract) extract obtained from the refining of DAO (Deasphalted Oil) to produce Brightstock or a mixture of extracts which consists of from Brightstock TRAE (Created Residual Aromatic Extract) extract and one or more DAE (Distillate Aromatic Extract), TDAE (Created Distillate Aromatic Extract) and MES (Mild Extraction Solvates) process oils.

The subject of the invention according to patent application WO2011098096 is a method for the production of refined process oil, which includes as a production step the extraction of Brightstock extract (RAE) or a mixture consisting of Brightstock extract and one or more process oils, where the obtained product is a process oil containing polycyclic aromatic compounds < 3% (m/m), which can be used as a softener or plasticizer for rubbers and their mixtures. The patent description RU2659794C1 discloses a method for obtaining non-carcinogenic plasticizers for rubber and rubber from a vacuum distillate obtained from crude oil, consisting in selective two-stage extraction with solvents N-methylpyrrolidone, furfural or phenol, and mixing the extract from the second refining and the extract in an appropriate proportion. from the first refining.

The patent description US 9567532 B2 presents the preparation of a TDAE and TRAE plasticizer in selective refining processes of an aromatic extract from a vacuum distillate or deasphaltate (DAO), in which the solvent is a mixture of dimethylsulfoxide and N-methylpyrrolidone, with the weight ratio of dimethylsulfoxide to N-methylpyrrolidone being in range 1: 0.1-0.5.

The patent application US20120181220A1 describes the process of producing an aromatic plasticizer with an aromatic carbon content of over 20% by weight, a polycyclic aromatic content of less than 3% by weight, an aniline temperature lower than 80°C, a kinematic viscosity from 15 to 30 mm ² /sw 100 °C and a flash point higher than 250°C in selective refining processes of aromatic extract from vacuum distillate or deasphalt (DAO); followed by mixing these extracts and solvent refining such mixture with solvents selected from the group consisting of furfural, N-methylpyrrolidone, dimethylsulfoxide, propylene carbonate and mixtures thereof.

Petroleum plasticizers are a very important component of rubber products and significantly affect their operational properties. The function of mineral softeners is, among other things, to modify the physical properties of rubber, especially by improving tensile strength, hardness, tear strength and elasticity at low temperatures.

In solvent extraction processes, in order to increase the efficiency of the process and its selectivity, the addition of a second solvent, also called a co-solvent, can be used. Generally, the second solvent influences the extraction process as an anti-solvent or enhances the effect of the primary solvent, that is, it may act opposite or in parallel to the primary solvent. A co-solvent in a liquid-liquid extraction process can increase extraction efficiency in two ways:

• acting opposite to the main solvent - reduces the solubility of the main solvent and facilitates re-extraction of the desired components into the raffinate phase, • acting in parallel with the main solvent - increases the polarity and selectivity of the main solvent, changes the liquid-liquid equilibrium distribution and affects the yield and quality of the product.

The 2003 patent US2003100813 presents an improved solvent extraction process using furfural for vacuum distillates processed to obtain base oils by adding a co-solvent to the main solvent. The co-solvent function was best performed by aliphatic amides or amide mixtures added to the basic solvent.

In the article entitled “Extraction of Aromatic Hydrocarbons from Lube Oil Using Different Co-Solvent” (Ibtehal K.S., Muslim A.Q., 2015 Extraction of Aromatic Hydrocarbons from Lube Oil Using Different Co-Solvent. Iraqi Journal of Chemical and Petroleum Engineering 16(1):79-90 ) presented research conducted on the influence of the addition of a co-solvent on the solvent extraction process of two types of fractions obtained from the vacuum distillation installation at the Daura refinery in Baghdad. In the presented work, formamide and N-methylpyrrolidone mixed with furfural in various proportions, which were used for one-step solvent extraction, were described as co-solvents.

In the article entitled “Role of water as the co-solvent in eco-friendly processing oil extraction: Optimization from experimental data and theoretical approaches.” (Luo T., Zhang L., Zhang C., Ma J., Zhao S., 2018, Role of water as the co-solvent in eco-friendly processing oil extraction: Optimization from experimental data and theoretical approaches. Chemical Engineering Science 183(29):275-287), studies conducted in China on solvent extraction using furfural as the main co-solvent for the removal of polycyclic aromatic compounds (PCA) from high-aromatic petroleum fractions are described. In order to increase the selectivity and efficiency of the product obtained in the process, water was introduced as a co-solvent and its influence on the extraction process was examined.

The essence of the present invention is the use of a vacuum distillate with a boiling range of fraction 5 + 95% 395 + 590°C and a refractive index No. ⁷⁰ below 1.528 from paraffin-sulfur-asphalt crude oil, which is subjected to a single refinement with furfural, for the production of an aromatic petroleum plasticizer. whereby the refining is carried out under strenuous process conditions, obtaining an extract characterized by a refractive index of No. ⁷⁰ not lower than 1.5350, a PCA content of approx. 12.8% and a kinematic viscosity at 100°C of approx. 34.5 mm ² /s. This extract is then selectively refined with a mixture of furfural and co-solvent formamide to obtain a raffinate that meets the requirements of the TDAE plasticizer.

According to the invention, the method for producing the TDAE petroleum plasticizer consists in the fact that a vacuum distillate from paraffin-sulfur-asphalt crude oil, with a fraction boiling range of 5 + 95% 395 + 590°C and a refractive index No. ⁷⁰ below 1.528, is refined with furfural at

PL 244776 Β1 mass ratio of distillate:furfural equal to 1: 2.7 4- 3.9 and extraction temperatures: bottom of the column 82 η- 101°C, top of the column 109 4- 126°C, and then the obtained extract, after the separation of furfural, is subjected to re-refining with a mixture of furfurol and co-solvent formamide with a content of 5% to 10% m/m, based on the mass of the solvent mixture, at a mass ratio of extract: (mixture of furfurol with formamide) of 1:1.0 4-2.0 and a temperature extraction: bottom of the column 75 4- 102°C, top of the column 105 4- 132°C and a raffinate is obtained which, after distilling off the solvents, meets the requirements of the TDAE petroleum plasticizer.

Preferably, a vacuum distillate from paraffin-sulfur-asphalt crude oil is refined, which has a boiling range of fraction 5 4-95% 465 4- 565°C and a refractive index no ^{. 70} below 1.515.

Preferably, vacuum distillate refining is carried out with furfural at a distillate:furfural mass ratio of 1:3.1 4-3.4 and extraction temperatures: bottom of the column 87-4-96°C, top of the column 116-4-122°C.

Preferably, the extract obtained after the separation of furfurol in the extraction process is refined to a mass ratio extract: (mixture of furfurol with formamide) ranging from 1: 1.2 4-1.60.

Preferably, the extract obtained after the separation of furfurol in the extraction process is refined in the extraction temperature range: bottom of the column 80 4-95°C, top of the column 110 4-122°C.

The method according to the invention enables the production of an aromatic plasticizer with a high content of aromatic hydrocarbons and a low content of polycyclic aromatic PCA compounds, meeting the requirements for the TDAE plasticizer, while the introduction of a co-solvent allows the process to be carried out at temperature conditions at the bottom and top of the extraction tower similar to the conditions for refining vacuum distillates with furfurol, which is beneficial for the proper conduct of the refining process and a higher selectivity of the process is observed as well as an increase in the yield of the obtained raffinate compared to refining with furfurol alone.

The effect of increasing extraction temperatures is the result of a change in the critical solubility temperature (KTR). Based on many years of experience, it is known that during solvent refining processes, temperatures maintained in the upper part of the extraction column should be 15°C to 20°C lower than the marked critical temperatures to ensure appropriate phase separation and achieve good selectivity of the extraction process.

KTR - this is the lowest temperature at which the solvent mixture with the input is still a single-phase solution; lowering the temperature of a given solution below the critical solubility temperature causes the solution to separate into two phases. Changes in critical temperatures for the given furfurol and furfurol + formamide systems with the EKST 1 extract are presented in Table 1 A, while the graph of the critical solubility temperature curves is shown in Figure 1 A.

Table 1A Critical temperatures for the EKST 1 fraction and furfural and furfural with formamide

Mass ratio of solvent to raw material Critical temperature °C For the system with furfural For the system with furfural + 5% formamide For the system with furfural + 7.5% formamide For the system with furfural + 10% formamide 1.4 : 1 78 105 126 134

The subject of the invention is explained in the embodiments presented below.

Example 1

Vacuum distillate from paraffin-sulphur-asphalt crude oil with a boiling point of the 5% fraction of 420°C and a boiling point of the 95% fraction of 581°C, refractive index no ^{. 70} 1.5017 and kinematic viscosity at 100°C 17.8 mm ² / s were subjected to selective refining with furfural at a distillate to furfural mass ratio of 1:3.3 and extraction column temperature: bottom of the column 88°C, top of the column 117°C, obtaining an extract with a yield of 48.3%, characterized by a refractive index of no ^{. 70} 1.541 , PCA content 13.8% and kinematic viscosity at 100°C 38.2 mm ² /s and other quality parameters presented in table 1 (marked EKST 1).

PL 244776 Β1

Table 1 Physicochemical properties of the obtained EXST 1 extract

No. Type of marking EXT 1 Test methods 1. Density at 20°C, g/cm ³ 0.9922 PN-EN ISO 12185:02 2. Kinematic viscosity at 100°C, mm ² /s 38.02 PN-EN ISO 3104:04 3. Kinematic viscosity at 5(°C), mm ² /s 817.6 PN-EN ISO 3104:04 4. Light switching factor at 20°C 1.5612 PN-81/C-04952 5. Sulfur content, % (m/m) 3.29 ASTM D 7039-15a 6. WZA content, % (m/m) 13.8 IP 346 7. Viscosity density constant VGC 0.9031 ASTM D 2140 8. Carbon content in structures. % C _A C _N c _P 31.18 8.01 60.81 ASTM D 2140

A sample of the extract (marked as EKST 1) in the amount of approximately 5 kg was subjected to the refining process with a mixture of furfural and co-solvent formamide, where the formamide content was 7.5% m/m, based on the weight of the solvent mixture.

The selective refining process with furfural or furfural with the participation of a co-solvent of extracts was carried out continuously on a large laboratory column with dimensions:

height 2300 mm, inner diameter 36 mm, filling - glass Raschig rings, dimensions 0-6 mm and height 6 mm.

The column segments were electrically heated with the possibility of smooth temperature regulation. Furfural or furfural with a co-solvent was fed to the top and the raw material to the bottom of the column using a laboratory plunger dosing pump.

The total column loading of raw material and solvent was maintained at 2 kg/h. The raffinate solution was collected from the top of the column and the extract solution from the bottom of the column. In order to distill solvents from raffinate solutions, a stripping distillation process with superheated steam was carried out.

Table 2 presents: technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer.

PL 244776 Β1

Table 2 Technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer

Laboratory raffinate R 1390 Refining conditions raw material EXT 1 solvent Furfural + 7.5% formamide mass ratio of the furfural-formamide mixture to the input 1.4 : 1 temperature at the top/bottom of the column, °C 105/85 column load, kg/h 2 - raffinate yield calculated per charge, %(m/m) 54.6 Properties of TDAE raffinate Density at 20°C, g/cm ³ 0.9618 Kinematic viscosity at 100°C, mm ² /s 24.88 Kinematic viscosity at ^r temp. 50°C, mm ² /s 314.1 Refractive index n _D ²⁰ 1.5390 Sulfur content, %(m/m) 2.95 Content of WZA, %(m/m) 2.8 Carbon, content in structures, % C _A Cn Cp 26.97 20.10 52.93 PAH content, mg/kg benzofalpyrene benzo[e]pyrene benzo[a] anthracene chrysene benzo[b]fluoranthene Ί benzo[j]fluoranthene > benzo[k]fluoranthene J dibenzo [a, h] anthracene total PAHs <0.4 <0.6 <0.5 <0.8 < 1.2 <0.2 <3.7

Example 2

A sample of the extract (marked as EKST 1) in the amount of approximately 5 kg was subjected to the refining process with a mixture of furfural and co-solvent formamide according to the principles of procedure described in Example 1, with the difference that the refining process was carried out with a mixture of furfural and co-solvent formamide, where the formamide content was 5% m /m, based on the mass of the solvent mixture.

Table 3 presents: technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer.

PL 244776 Β1

Table 3 Technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer

Laboratory raffinate R1391 Refining conditions raw material EXT 1 solvent Furfural + 5% formamide mass ratio of the furfural-formamide mixture to the input 1.4 : 1 temperature at the top/bottom of the column, °C 100/80 column load, kg/h 2 - raffinate yield calculated per charge, %(m/m) 52.1 Properties Density at 20°C, g/cm ^J 0.9598 Kinematic viscosity at 100°C, mm ² /s 24.41 Kinematic viscosity at 50°C, mm ² /s 306.1 Refractive index n _D ²⁰ 1.5363 Flash point, °C 268 Sulfur content, %(m/m) 2.60 Content of WZA, %(m/m) 2.6 Carbon, content in structures, % C _A Cn C _P 25.76 23/08 51.15 PAH content, mg/kg bcnzo[a]pyrcn bcnzo[e]pyrene bcnzo| a | anthracene chrysene benzene b| fluorine antennae 1 benzoyl [fluoranthene > benzo[k]fluoranthene J dibcnzo[a,h]anthraccn total PAHs <0.4 <0.5 <0.4 <0.7 < 1.0 <0.2 <3.2

Example 3

A sample of the extract (marked as EKST 1) in the amount of approximately 5 kg was subjected to the refining process with a mixture of furfural and co-solvent formamide according to the principles of procedure described in Example 1, with the difference that the refining process was carried out with a mixture of furfural and co-solvent formamide, where the formamide content was 10% m /m, based on the mass of the solvent mixture.

Table 4 presents: technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer.

PL 244776 Β1

Table 4 Technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer

Laboratory raffinate R1392 Refining conditions raw material EXT 1 solvent Furfural + 10% formamide mass ratio of the furfural-formamide mixture to the input 1.4 : 1 temperature at the top/bottom of the column, °C 112/92 column load, kg/h 2 - raffinate yield calculated per charge, %(m/m) 56.3 Properties Density at 20°C, g/cm ^J 0.9637 Kinematic viscosity at 100°C, mm ² /s 24.95 Kinematic viscosity at 50°C, mm7s 316.1 Refractive index n _D ^2U 1.5396 Flash point, °C 270 Sulfur content, %(m/m) 2.95 Content of WZA, %(m/m) 2.9 Carbon content in structures. % C _A C _n Cp 26.84 20.94 52.22 PAH content, mg/kg benzophaypyrene benzo[e]pyrene benzo[e]pyrene benzo[e]pyrene benzo[e]pyrene benzo[e]pyrene benzo[i] fluorine antennas ?- benzofk] fluorine of antennae J dibenzo |a, h] anthracene total PAHs <0.4 <0.7 <0.6 <0.8 < 1.3 <0.2 4.0

Example 4

A sample of the extract (marked as EKST 1) in the amount of approximately 5 kg was subjected to the refining process with furfurol without a co-solvent according to the rules of procedure described in example 1. Table 5 presents: technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer raffinate

PL 244776 Β1

Table 5 Technological parameters of the refining process, mass balance and properties of the obtained TDAE plasticizer raffinate

Laboratory raffinate R1393 Refining conditions raw material extract 1 solvent Furfural mass ratio of furfural to the input 1.8 : 1 temperature at the top/bottom of the column, °C 68/52 column load, kg/h 2 - raffinate yield calculated per charge, %(m/m) 36.2 Properties Density at 20°C, g/enr ¹ 0.9479 Kinematic viscosity at 100°C, mm ² /s 21.47 Kinematic viscosity at 50°C, mm ² /s 222.7 Refractive index _nD 1.5286 Sulfur content, %(m/m) 2.73 Content of WZA, %(m/m) 2.2 Coal. content in structures, % c _A c _N Cp 22.58 21.66 55.76

Claims (5)

1. A method for producing TDAE petroleum plasticizer, including refining with furfurol a vacuum distillate from paraffin-sulfur-asphalt crude oil, characterized in that the vacuum distillate from paraffin-sulfur-asphalt crude oil, with a boiling range of fraction 5 4- 95% 395 η- 590 °C, and the refractive index no. ⁷⁰ below 1.528, is refined with furfural at a distillate:furfural mass ratio of 1: 2.7 4- 3.9 and extraction temperatures: bottom of the column 82 4 - 101°C, top of the column 109 4 - 126°C, then the obtained extract, after the separation of furfurol, is re-refined with a mixture of furfurol and co-solvent formamide with a content of 5% to 10% m/m, based on the mass of the solvent mixture, with the mass ratio of extract: mixture of furfurol and formamide being 1 : 1.0 4- 2.0 and extraction temperature: bottom of the column 75 4- 102°C, top of the column 105 4- 132°C, and a raffinate is obtained which, after distilling off the solvents, meets the requirements of the TDAE plasticizer. 2. The method according to claim 1, characterized in that the refining is carried out by a vacuum distillate from paraffin-sulfur-asphalt crude oil, which has a boiling range of fraction 5 4-95% 465-4565°C and a refractive index no ^{. 70} below 1.515. 3. The method according to claim 1, characterized in that the vacuum distillate refining is carried out with furfurol at a distillate:furfurol mass ratio of 1: 3.1 4- 3.4 and extraction temperatures: bottom of the column 87 4- 96°C, top of the column 116 4- 122°C . 4. The method according to claim 1, characterized in that the mass ratio of extract: mixture of furfurol and formamide in the extraction process is in the range of 1: 1.2 4-1.60. 5. The method according to claim 1. 1, characterized in that the extraction process is carried out in the extraction temperature range: bottom of the column 80-4-95°C, top of the column 110-4-122°C.