SU701983A1 - Method of naphthalene purification - Google Patents

Description

The present invention relates to the field of naphthalene cleaning. Naphthalene is widely used as a feedstock for the organic synthesis industry. The proportion of naphthalene going to get phthalic acid apyaride is recently 5O-6O%. The remaining 40-5O% is used to prepare intermediates for dyes, surfactants, dispersants, insecticides, nitro and chloronaphthalene and syntans, DP Many chemical plants require purified 1st grade naphthalene (Tcr. 79.3 ° C). The main supplier of naphthalene is the coke-chemical industry. Industrial napouthine production of refined naphthalene is based on the use of sulfuric acid. The method consists in treating molten naphthalene with 93% sulfuric acid at 9O-1OO ° C. After washing with water, the product is rectified. 0.8 kg of naphthalene is lost per kg of consumed sulfuric acid; 1 kg of acid are consumed per 1 ton of purified product. The method has a number of significant non-residues: a significant loss of naphthalene .V by sulfonation, the presence of aggressive wastewater and acidic tar, the lack of regeneration of the spent sulfuric acid and strong corrosion of the apparatus. Known methods of cleaning technical naphthalene various adsorbents: activated carbon, alumina, coke, bentonite clays, aluminosilicates 2. Best reeult-. You are obtained when cleaning naphthalene with aluminosilicate chips with repeated regeneration of the latter. According to this method, molten extruded naphthalene containing 0.4% unsaturated compounds is passed through a layer of sorbent at a temperature of 100-12 ° C. Load on sorbet 0.5-1.0 part of naphthalene to 1 part of sorbent, the duration of pyhla to rogenation -48 -72 h. The process of cleaning naphtfuga soirovodots poppp-. GHG of sorption capacity of sorption and osgolization of non-necral compounds. If n is the first. About 70% of unsaturated substances are recovered from naphthalene, then after 00 hours only. At the same time, the content of the non-volatile residue in naphthalene increases, and after 00–1.00 h, it increases by a factor of 2–3 against the initial one. During the first 20-30 hours, the product is obtained, the crystalline temperature ™; The setting of which is O ,, 4 ° С is higher than the initial one (78.8 ° С). The amount of nitrogen-containing compounds decreases by a factor of 2.3, sulfur compounds by 20–30%. The color on the iodomegric color scale reaches 3-0 units (against 12-15 in the original). When cleaning n% 1 kg of the adsorbent, 0.5 kg of naphthalene is adsorbed, which, before regenerating the aluminosilicate, must be distilled off with live steam or roiDioHH gas to prevent contamination of the atmosphere. The main disadvantages of this method are the low selectivity of the aluminosilicate with respect to naphthalene impurities (nitrogenous, sulphurous to Heira compounds), a slight increase in the quality of the purified product compared to the original and the need to distill the adsorbed naphthalene from aluminosilicate. A known method for the preparation of Cristaplone naphthalene consists of M; that pairs of extruded naftaggin having a crystallization temperature of 78.4 ° C are passed over an aluminosilicate catalyst in a stream of air or inert gas at 3OO -38 ° C. To improve the quality of the product, the obtained catalyzate is subjected to subsequent distillation to purify naphthalene with a crystallization temperature of 79.6 80.03 ° C and a yield of 9 O, O - 92p7 / s per loaded. The disadvantages of this method are as follows: temperature, which leads to coking of the catalyst, the complication of the process technology associated with the need. . the introduction of the stage of distillation of the obtained Ea, as well as the relatively low yield of the purified product; The closest in technical terms to the proposed method is the 7 3 CLEANING naphtha; | talina in gokch ps.p.RoRa Gaza ppi teke narveDe: .i C.IOU GOSHEH:: J.: O - 1.1, On .YY7- with NOI KO.PONKKY. .9 (| Thlg: .. g ,.; V V;, P e. P V l south in the cr - C1-Л L11ches k {af -: -:: roiiepaiii-iBi-; aticoNOiii.:;: and: -:: .uiduvog; -HD -g: hieratures on (losavio:, -: temperagura of purification; cx - with this, practical, 1, i, but desorption of residual; g-, bayt 11aft. ina (after cho (incL regeneration made from OJL) 400-0 ОО ° С next about sorption. I ieaocfa yKciMK, ::;: ii :-): 4 .., i мОС.; :: :: thats its izha prodiazpdigchelsg naphthalene (weight h-oposphe se nest lkn: zeolite 1; in - l; 1 2) :: {;: LSE ii: logical a:. connection with a short cycle of reboot: l and sogbep-kch: regeneration to a larger number; from “piebald and .. The purpose of the present Hrjotjpci-eini /: -. is simplification of techno. and) otk: ss; -yrgygr; -h-h. Delivered to reach 1. in a different way o -.m- (Art. nlta.ll by passing gyears and Phta; current of air or KNerT11010 GE -; ::; -: -: P1 increased temperature through cjiofl ats sorbent. zeolite type: X, soccerzhdg). e th cations Ma, Co, A6 g, iix mixture. The process is preferably carried out at a temperature of 15 ° 200 ° C. The difference of the proposed method consists in the use of a type X zeolite, containing 1B, listed cations, as an adsorbant. Characteristics of the components used to clean up naphthalene drive 3 tab. 1 and 2.

Characterization of zeolites used in naphthalene cleaning pl

Table 1

Type X zeolites have a significantly larger capacity compared to naphthalene primes compared to type A zeolys and allow to increase the productivity of the process by increasing the naphthalene: zeite ratio from 1: 6 to 1:12 for zeolites tHna A Hb 1: 1.5 1: 0.13 for type X zeolites while maintaining the high quality of the purified product. In addition, p) that cleaning naphthalene on zeolites, type X, drastically reduces the number of regenerations, which simplifies the process technology.

The naphthalene cleaning process is carried out as follows. Molten naf. talin is evaporated in a stream of air or inert gas, and the resulting vapor-gas mixture is fed to the adsorption cone injected with zeolite. Upon contact of naphthalene with the surface of the zeolite at a temperature of 150–200 ° C, the selective adsorption of naphthalene impurities (indole, indene, benzonitrile, 1st 2 methylnaphthalenes, difope, and cp) occurs. The purified product at the outlet of the column is cooled and recovered. zkde crystals. After the end of the adsorption process, the temperature in the column is increased by 30–5 ° C and the zeolite is rinsed with nitrogen or air for about 10 minutes; -30 min. Then the neolithic layer is regenerated by air blowing, gradually increasing the temperature in the column to 365 C. The desorption products are captured, and the regenerated zeolate is used for the adsorption process,

hia zeolites of Tina X of the flow of different types of raw materials: pressoaznaph naphthalene, naphthalene fraction to the msg.

a mixture of naphth-ali, indan, indone, benzonitrile; thio naphthene, 2 methylnaphthalene and indole. The results of the artificial mixture on the zeolites of type X are given. Е

tab. 3. From the data in the table, it is clear that they are best removed from naphthalene. indole on zeolites NaX, Wed ChaH, fA.nNuK. CoCa WaX.NiNaX, and back oxyfmn-on molecular sieves С С oi But, Y.,

Ж N01X, Ni Со Mach, МпСа Na I, Мп т X Zeolites Мп Со No X, ССхз | YD X, Mi MoH; selective with respect to inden. In the result of cleaning, for example, on the Cc To DHh with respect to weight naphthalene:

a zeolite equal to 4 is achieved by complete removal of α-naphthalene indole, indene, and benzonitrile with indetep content. indene in the initial mixture is 0.4%, and fr / 4-; s nitrile is 0.35%, the quality of 2 ... mbtiliuf-. talin decreases from 0.5 to 0; 22%, and indane from 0.4 to 0.026%.

The introduction of Cd Mi, Co cations, the initial sample of zeolite 1CAaA increases its capacity relative to the naphthalene impurity, which can increase the amount of purified naphthalene by a sorbent unit.

The results of purification of the naphthalene fraction on zeolites with different cation contents are presented in Table. 4. The naphthalene fraction is cleaned at a naphthalene: zeolite ratio of 1: 0.9, under conditions similar to those shown in the examples of the application. The naphthalene fraction of the West Siberian Metallurgical Plant, containing,%: naphthalene, 88.98; was used as the initial syr; indane 0.098;

indene 0,045; -benzonitrile 0.1 About; thion phtene, l, O92f methyl naphthalenes 4.187; quinopine 1,671; dnphenyl 0.085; dimethylnaphthalenes 0.542; indole 0.675; other aromatic and heteropianic compounds, 2.519j, having a crystallization temperature of 74.20 ° C, a color of 44.5, and an iodine content of 4.35. These tables show that on zeolites with the indicated cation limit of 2 cations, purification of naphthalene fractions is indicated, while in the purified product the content of impurities decreases, and the crystallization temperature of the resulting naphthalene increases by 3.45 compared to the initial product. . four,.

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n Example 1. 20 I cm "C containing,%: naphthalene 97,15; indshna 0.4 indana 0.4; benonitrile 0.35; ildena 0.4 ;, thioneaphene 0.6; 2-methyliaphthalene O., 5; other impurities 0.2, in the molten state, are continuously fed into the evaporator (temperature 200 ° C), into which dry nitrogen enters. The resulting gas-vapor mixture of naphthalene with nitrogen is passed: through a column with zeolite MAX (weight 4.6 g), proportionally, naphthalene: zeolite 1: 0.23. The conditions of the experiment are as follows: the zeolite grain size is 0.5–1.0 mm, the length of the adsorbent bed is 35 mm in diameter, the column diameter is 18 mm, the temperature is 150 ° C, the gas flow rate is 3,810 hours, the naphthalene concentration in the vapor – gas mixture is 0.353 g / l nitrogen. Naphthalene at the outlet of the column is cooled and condensed. Get D9 g of the product containing,%: naphthalene 99,0; indana 0.023; indene 0.090. thiocaphthene 0.535; 2-methylnaphthalene 0,228, The yield of the purified product per 100% naphthalene 97, O%. The regeneration of the zeolite is carried out as follows. The temperature in the column is increased by 30-50 ° C compared with the adsorption process and the layer of deolite is flushed with gas for 30 minutes. Then gradually increase the temperature in the layer of sorbent, blowing it with air. The zeolite purge mode is as follows: temperature 200 C - purge time 60 min, temperature 25 C - purge time 6 O min., Temperature 300 C - purge time 60 min, temperature 365 C - blow time 3-5 h. Volumetric gas velocity 1100 h. The desorption products are captured, and the regenerated zeolite is again used for the adsorption process. Example 2. For the purification of 28 g of a mixture of naphthalene and impurities, the composition of which is given in Example 1, use is Ca NaX zeolite. Analogous experiments described in Example 1, naphthalene: zeolite Ca NaX ratio 1: 0.16. 26.6 g of product are obtained, containing:%: naphthalene 99.0; indana 0.023; thio-naphthene 0.570; 2-methylnaphthalene .276. The input of purified naphthalene per 10O% is 96.8%. Zeolite is regenerated in the same way as described (see example 1). Example 3. The composition of the raw material and the conditions of purification are similar to those given in Example 1. 36 g of a mixture of naph alina n iffiUMocoh- n | ioayciK / iiir × (Lai Zeapit AAVi Pps 1.8 g, diaeTfi: :) Bf) Neopite OH 0.5 - n2G mm, naphthalene phyiiioirno: g-eolns 1: 1, i:. „toluene1P -.- 1st prop. (3-1:, 4 g) cor (.oii:; iiT 99.1% naphthalene, OD) I 7% incan, 044% ince, O, 1 2.-methylnaphthine and 0, about 34% thio1) 41 tons . Gd3khol o1eno1 0 naphthalene EL calculation. MA 1 0 (j% is 07.5%. The horny horizon is produced by blowing the sorbent bed / j under the hood of the conditions of example i. PREMI f) 4, -TO g pres ;;:. Ynno afftalin containing,%: naphthalene 8.78; intsena 0.024; thionaphthene, 746; 2-MetSh1-naphthalna 0.202; info sludge 0.113; indole 0.130. (tampvigl-.o 1 a crystallization (color 8.1, the iodko number is 0.984) are plated and i; Serp; s are fed to the evaporator. The naphthalene steam and vapor mixture in t-ocean of dry nitrogen is passed through a layer of rigaCaYchHuch, adsrrbionio1 coyopsy; (weight of zeolite 8.0 g, the length of the layer of sorbent 5 g; m, the ratio of naphthalig: zeolite 1: 0.16; tI -oO, -. 1 temperature of experience 1. zO S.-, size 1 mirrored zeolite. Oh, oh - 1.0 mm. Sampling, gas velocity 1O22.2 ac, naphthalene concentration in riapora3 () mixed O, 9.23 r / .i of nitrogen. 48 g is obtained- iipoayKi-a, co.,% : naphthalene 5,9,13; knnda 0, OOZ; thiafteg; a 0.743; 2-metstnnaf - talin a 0.104, (temperature. 79.71 ° C, color-2.2, Kitsiyo number 0.19). The output, in naphthan in the calculation, are 100% - 97.2%. The Neolithic is regenerated with a blown sorbent air layer in the conditions of example 1 .. Example 5. 4 .- paftalylopoy f). Stocks, contents,%: 1a | gagalin 89, 5O; indan O, 092; nndena O, 055, benzonitrile 0.056; thio; aften 0.980; 2-methylnaphthalene 2,589; 1 - methyl 1) taline 0.695; diphenyl 0.988; dimethyl naphthyles 0.4-11; indole 0.675; other aromatic and heterocyclic compounds 3.96, (crystallization temperature 74.49 ° C, color 43.6. and the number 4.35) melted and continuously fed to the evaporator. The resulting gas-vapor mixture with nitrogen n; :) opus: cabin h-eres SacMax (zeolite weight 6.0 g, sorbent bed length 4.5 cm) with a naphthalene: zeo-lit. ratio of 1: 1, .3. Experimental conditions of ana.pogichny described in example 4. Receive :: 1u-3,4.5 g of purified naphthalene sodor (a; tsego,%: p: afalinin 98.98; indene 0, OOZ; thio1 aftench 0.915; 2-methylnaphthalene 0.075; other impurities 0.027 (crystallization temperature 79, G2 ° C, color 3.5, iodine value 0.24). The yield of the purified product per 100% naphthalene is 95.4%. The regeneration of the zeolite is carried out similarly to that described ( see example 1.) Example 6. 2O, O g of the naphthalene fraction is passed through a layer of zeolite C a Na) C ,. The composition of the fraction and the purification conditions are analogous to those described in example 5, the naphthalene: zeolite 1 ratio: 0.3. Obtain 17.7 g of purified naphthalene containing,%: naphthalene 97.9 O; indane 0.008; indene 0.012; benzonitrile 0, OOZ; 1,2-1ethylnaphthalenes 0.853; thionaphthene 0.922; diphenyl 0.027 and other impurities 0.275, (crystallization temperature 78, okra ka 4.0, iodine number 0.35). The yield of the purified product per 100% naphthalene is 96.7%. The regeneration of the zeolite is carried out as described (see Example 1). Type X zeolites offered in this method have a high adsorption capacity and can be used to clean naphthalan from impurities with a high content of unsaturated and nitrogenous compounds in the feedstock. The proposed adsorbents are regenerated and can be used many times. A preliminary feasibility study shows that using type X deupites to clean naphthalene has advantages over using type A zeolites, which are 4-10 times larger. process performance and reducing the number of regenerations of zeolite, which will increase its service life and simplify the process technology. Devices: 1. The method of cleaning naphthalene by passing naphthalene vapor in air current or inert gas at elevated temperature through a layer of zeolite adsorbent, differing in that. that, in order to simplify the process technology and increase its productivity, a zeolite of the type is used as an adsorbent, containing co.t Mn cations, ZI. Or their mixture. 2. The method according to claim 1, which is also distinguished by the fact that the purification is carried out at a temperature of 15 to 200 ° C. Sources of information, take into account in the examination 1. M. Litvinenko. Chemical products of coking. Technique, Kiev, 1974. p. 157-164, 2.f thorns c. and A. L. Babaeva. Preparation of technical naphthalene for the production of phthalic anhydride. Coke and Chem. 1973, No. 4, p. 34. 3. Copyright certificate № 278664, cl. C 07 C 15/24, publ. 1962. 4. Copyright certificate for the route No. 2172162/04, GCL, C O7 C 15/24, 1975.