Ph.D., Ziyadullaev O.E., prof. Ikramov A.I.

Lecturer Abdurakhmanovа S.S., masters Juraev R.S.

Tashkent Chemical Technological Institute, Uzbekistan

SYNTHESIS OF VINYL ESTER AROMATIC ACETYLENE ALCOHOLS BY THE OF HETEROGENEOUS

CATALYTIC METHOD

Acetylene is one of the key types of chemical raw materials, notably in potesnenny 60 petrochemicals ethylene and propylene, is now once again drew the attention of researchers and technologists. Reason is the progressive rise in oil and gas on the world market [1, 2].

As is known, most of the chemical reactions of acetylene requires energy input, but rather it is accompanied by the release. There are many prerequisites to become the acetylene in the future as a raw material for industrial organic synthesis [3, 4].

Systematic studies vinylation reaction of alcohols acetylene tends to strengthen the theoretical concepts of nucleophile addition to the triple bond and the continuous improvement of synthesis of vinyl esters (VE) diverse structure [5].

The reaction of acetylene with aromatic acetylene alcohols in the presence of a catalyst system CsF-NaOH-DMSO 80-120 ^oC (6 hours) and pressure of acetylene leads vinyl ethers yield of 75-90% [6].

When industrial implementation of heterogeneous catalytic processes have to adjust the speed and direction of chemical reactions, the mechanism of which is known only in the most general terms, and the catalysts are complex solids, properties which are still not fully understood, and that may include almost all the elements of the periodic the periodic system [7].

In this study of heterogeneous catalytic process to synthesize certain vinyl esters of aromatic acetylenic alcohols in relatively high yields in the presence of MOH systems impregnated activated carbon. The active component of the catalyst used hydroxides of sodium and potassium. The process carried out at different temperatures and reaction time.

Studied the influence of the nature of the catalyst, the molar ratio of the starting reactants, the reaction time and temperature on the heterogeneously vinylation AAA. Also studied acetylene feed rate to the process, the energy consumption, process control. Conducted separation drying, purification and isolation of the product, catalyst regeneration, catalyst lifetime defined, its repeated use, process parameters of the reaction (control, dimensions and volumes of the equipment).

The following scheme is proposed vinylation reaction AAA heterogeneous catalytic process in the presence of acetylene:

here: R= -H, R^I= -C₆H₅; R= -CH_3, R^I= -CH₃; R= -CH₃, R^I= -C₂H₅; R= -CH_3,

R^I= изо -C₃H₇, R= -CH₃, R^I= -C(СH₃)₃; R= -CH₃, R^I= -С₆H_3.

The influence of the nature of the AAA catalyst and the molar ratio of the starting reactants on the yield of the product. At the same time used as the catalyst NaОН/С_аct. and KОН/С_аct.. Reactions performed at 200 °C for 3 hours.

Results of the experiments showed that with the increase of acetylene ratio: AAA observed increase in yield. For example, in the presence of a catalyst NaОН/С_аct. with increasing ratio AAA and acetylene from 1:1 to 1:5 yield vinyl ethers increases, respectively, I= 31,6; II= 33,6; III= 32,6; IV= 35,5 and V= 26,0%.

Reducing the amount of acetylene alcohol concerning adversely affects the yield of the product, since when the initial reagents equimolar ratio, respectively, yield vinylethers is I= 52,3; II= 47,6; III= 43,0; IV= 38,4 and V= 60,0%. When the ratio of acetylene alcohol and 5: 1 was synthesized with a yield of VE AAA respectively I= 12,8; II= 11,3; III= 8,90; IV= 7,50 and V= 16,4%. The reason for the high secondary yield with increasing ratio of acetylene alcohol concerning the acetylene is adsorbed to the catalyst. Further undergoes physical adsorption, chemisorption, and then. The adsorbed acetylene molecule in the active center of the catalyst forms ρ-complexes and become intermediates, connecting the past with alcohols to form VE. If not saturated with acetylene AAA alcoholates, then connects with catalyst AAA supplied to the reactor which prevents the acetylene reacted, whereby the output VE decreases. When using more active KОН/С_аct.. instead of NaОН/С_аct. an increase in yield.

Table 1.

Impact of the molar ratio of the reactants and the nature

of the catalyst on the yield VE AAA

Catalyst	alcohol:acetylene	products (I), %	intermediate products	products (II), %	intermediate products	products (III), %	intermediate products	products (IV), %	intermediate products	products (V), %	intermediate products
NaОН/Саct.	5:1	12,8	43,0	11,3	48,2	8,90	53,1	7,50	56,5	16,4	39,2
	4:1	17,6	36,0	13,4	46,2	12,6	49,2	10,5	52,5	25,2	34,0
	3:1	21,0	33,2	18,6	43,0	15,2	46,0	14,3	49,0	28,4	28,6
	2:1	29,8	26,3	22,3	34,8	18,4	39,2	16,5	42,6	32,5	24,5
	1:1	52,3	21,4	47,6	27,4	43,0	33,0	38,4	36,0	60,0	19,0
	1:2	66,4	17,6	62,0	23,0	58,3	26,0	44,3	31,0	69,7	16,2
	1:3	82,3	13,1	79,6	18,6	74,2	21,3	71,0	24,2	84,7	12,8
	1:4	83,4	12,6	80,7	16,4	75,0	19,9	73,1	21,0	85,3	11,3
	1:5	83,9	10,7	81,2	12,6	75,6	17,9	73,9	18,3	86,0	10,0
KОН/Саct..	5:1	14,3	38,2	12,3	43,0	10,8	46,0	9,75	49,3	19,6	36,3
	4:1	21,0	33,0	17,2	39,0	15,5	41,3	13,4	43,5	27,6	28,0
	3:1	28,6	31,1	25,4	36,2	21,2	38,4	18,4	41,0	31,0	23,1
	2:1	34,3	22,7	30,0	30,1	26,2	36,2	22,3	36,4	38,4	21,7
	1:1	58,4	18,3	55,2	21,0	49,3	22,4	42,4	23,0	63,8	16,2
	1:2	70,4	15,0	66,6	18,6	62,3	19,2	58,4	22,7	78,4	13,1
	1:3	84,7	11,3	82,3	14,3	77,7	15,3	74,4	18,2	87,3	10,1
	1:4	85,1	10,6	82,3	13,5	78,2	14,0	75,3	17,3	88,5	9,40
	1:5	86,2	8,80	84,1	11,4	79,3	12,3	76,2	16,4	88,9	8,35

here: I- VE 1-phenyl-3-methylbutyn-1-ol-3;

II- VE 1-phenyl-3-methylpentin-1-ol-3;

III- VE 1-phenyl-3,4-dimethylpentyn-1-ol-3;

IV- VE 1-phenyl-3,4,4-trimethylpentyn-1-ol-3:

V- VE 1,3-diphenylbutyn-1-ol-3.

Investigation of the influence and the nature of the catalyst and the ratio of the initial reagents to yield to determine the optimal molar ratio AAA acetylene 1:3. Under this condition on the catalysts NaОН/С_аct. and KОН/С_аct.. VE obtained the following outputs, respectively: I= 82,3 and 84,7%; II= 79,6 and 82,3%; III= 74,2 and 77,7%; IV= 71,0 and 74,4%; V= 84,7 and 87,3%.

During vinylation with increasing molecular weight of the AAA by a secondary yield decreases. AAA atom which fits acidity i.e., the mobility of the hydroxyl group of hydrogen carbon bonded hydroxyl containing radical phenyl-1,3-diphenyl-3-methyl-butyne-1-ol-3 due to the induction effect of the hydroxyl hydrogen is activated and increases the yield of vinyl ether.

Table 2

Dependence of the VE AAA on the nature and amount of catalyst

Catalyst	Amount МОН, mass.% in Саct/	VE AAA, %					Average speed of the reaction, mol/l.hour
		I	II	III	IV	V	I	II	III	IV	V
NaОН/Саct.	5	47,6	41,2	37,3	31,1	52,3	0,75	0,70	0,54	0,49	0,78
	10	70,2	67,4	63,2	61,1	77,3	1,31	1,34	1,16	1,14	1,38
	15	78,6	75,3	70,0	67,6	81,1	1,38	1,36	1,21	1,17	1,44
	20	82,3	79,6	74,2	71,0	84,7	1,41	1,39	1,28	1,22	1,46
	25	82,7	79,9	74,8	71,7	85,4	1,49	1,43	1,38	1,27	1,53
	30	83,1	80,3	75,5	72,1	85,9	1,52	1,32	1,26	1,21	1,56
KОН/Саct.	5	52,3	46,8	44,7	38,4	55,6	0,87	0,83	0,70	0,68	0,97
	10	74,7	72,4	68,4	63,5	79,1	1,39	1,35	1,27	1,22	1,43
	15	82,2	80,3	74,6	68,3	82,8	1,47	1,43	1,36	1,31	1,52
	20	84,7	82,3	77,7	74,4	87,3	1,53	1,47	1,45	1,42	1,57
	25	85,2	82,8	77,9	75,1	87,6	1,56	1,50	1,46	1,38	1,62
	30	85,7	83,1	78,6	75,4	88,0	1,59	1,53	1,49	1,42	1,64

The results showed that when the active component is up to 20%, an increase in the secondary yield AAA. For example, in the presence of NaОН/С_аct. with the amount of NaOH of 20 mass.% VE AAA formed with the following outputs: I= 82,3; II= 79,6; III= 74,2; IV= 71,0 and V= 84,7%. When the content of the catalyst is increased to 25-30 mass.%. Was observed a slight increase in yield.

Thus, we investigated vinylation AAA heterogeneous catalytic process. The optimal conditions for the synthesis of VE AAA: duration of experiment 3 hours ratio AAA:acetylene = 1:3, catalyst KОН/С_аct.. The reaction temperature of 200 °C.

Synthesis of VE AAA homogeneity catalyst compared to heterogeneous catalytic process is economically cheaper, convenient and environmentally friendly, relatively few are produced intermediate and by-products. At the same time, we know that the processes of synthesis of homogeneous VE AAA method used expensive materials, equipment consume a lot of energy, which in turn will lead to higher cost of production.

Due to the ease of management and control, security, stability, intermediate and final products, the formation of a small amount of intermediate metal complex salts, phenol, phenylacetylene, styrene, enol, acetal alcoholates heterogeneous method is more effective than homogeneous.

Vinylation reaction with aromatic acetylenic alcohol heterogeneous methods. The influence of the nature and amount of catalyst, the molar ratio of the starting materials during the reaction temperature on the yield of the product. Definitely purity, structure, elemental composition and physical constants and quantum chemical calculations of the synthesized compounds. The optimal conditions for the synthesis of a product with a high yield.

Literature:

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6. Ziyadullaev O.E., Mirhamitova D.H., Nurmanov S.E. Synthesis of 1-Phenyl-3,4-dimethylpentyn-1-ol-3 and its vinyl ether // Journal Reports of the Academy of Sciences of Uzbekistan. Tashkent. 2012. №3. pp. 40-45.

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