SU1004334A1 - Process for producing norbornadiene - Google Patents

Description

(54) METHOD OF OBTAINING NORBORNADIEN

The invention relates to a method for producing norbornadiene (NBD) or bicyclo (2.2.1) heptadiene-2.5, which is a raw material for the manufacture of insecticides such as aldrin and dieldrin.

 The main method for obtaining NDB is the reaction of diene synthesis between Dicyclopentadiene (DCPD) or its monomeric form, cyclopentadiene (CPD) and acetylane.

The reaction is carried out at elevated temperatures of 370-380 ° C, acetylene pressure of 4 atm, and CPP: acetylene molar ratio of not less than 1: 1.3. The selectivity of the reaction is 70.1%, the NWD content in the reaction products is 26.1 wt.% T The disadvantage of the known method of producing NDB is the use of excess acetylene (not less than

30 mol.% In relation to the JRS or

LDCPD), firstly, due to the low acetylene conversion (about 30-35%)

leads to its overspending, and secondly, to explosion hazard, since the process is carried out in the area of temperature and pressure data, where explosive decomposition of acetylene is possible. First of all, the continuous process of obtaining NBD has a low productivity — the rate of delivery of the CPD (DCPD) is 0.15, which leads to an increase in the reaction volumes of the apparatus. The increase in volumetric rate leads to a decrease in the output NBD.

Known methods for producing NVD

15 by the interaction of the CPD or its dimer with acetylene at 340 ° C and a pressure of 6-13 atm in the presence of a phlegmatizer of the explosive decomposition of acetylene. As a phlegmatizer were tested

20 nitrogen, isopropane, cyclopentadiene. The process is carried out at a volume ratio of C HgCPD of 1.5: 1, when using nitrogen as a phlegmatizer or at a volume ratio of (2-1): 1, when using CPP as a phlegmatizer

However, in order for the CPD to have a sufficient phlegmatizing effect, a very high

30 dilution of acetylene cpd at least

In the least, the content of the latter in the mixture with acetylene should be much higher than 50-60% by volume, since mixtures of this composition (C.%: CPD 1: 1) can explode even at, and the synthesis of NBD takes place at 370-380С. An increase in the content of CPP in the initial mixture above 50% leads to a sharp drop in its conversion and the content of NBD in the reaction products (up to 10-12%), which further complicates the distillation scheme for the separation of products, leads to large and unjustified recycling of the CPD and DTSPD, unprofitable from the point of view of energy technology process,

The aim of the invention is to simplify the process technology.

The goal is achieved by the fact that according to the method of obtaining a norborentz diene by the interaction of cyclopentadiene or its dimer with acetylene at ZUO-ZVO C, a pressure of 2.8 3 atm in the presence of water vapor at a molar ratio of cyclopentadiene: acetylene: water equal to 1: (1.05-1.1): 1-2.

The proposed method allows to reduce the consumption of acetylene by 15-20% without reducing the yield of NBD, since the added water vapor accelerates the reaction and increases the conversion of DCPD (CPD) with constant selectivity for the same CPP: acetylene molar ratios. At the same time, the productivity of the continuous NDB process is also increased, since the feed rate of the CPD (DCPD) increases to 0.35-0.37 per unit of the reaction volume of the unit. In addition, the addition of water vapor to acetylene in an amount of about 40% makes the process non-explosive even, for example, at .6 atm and that fully corresponds to the conditions of NBD synthesis. The molar ratio of TsPD: H2O 1: (1-2) for the interval relative to 11enr1y TsPD: acetylene 1: (1.05-1.1) according to the proposed method corresponds to the content of steam in the mixture with acetylene 47-65%, which is significantly higher than a couple guaranteeing the safe conduct of the process. The latter circumstance greatly simplifies and realizes the technological design of the continuous industrial process of obtaining NDB from the CPD (DCPD) and acetylene. Simultaneously adding steam in a high-temperature process makes it possible to better control the temperature conditions of the process.

Example Pi The synthesis of norbornadiene is carried out in a pilot plant of direct action. Acetylene from a cylinder with a speed of 135-142 nl / h, water vapor is fed into the reactor, which is a metal tube 2.2 m long and 25 mm in diameter, placed in a saltpetre bath at 370-380 ° C. (6 atm) 105-210 g / h and dicyclopentadiene 380-400 mp / h. Molar ratio cyclopentadiene; acetylene; water 1; (1.05-1.1); (1-2), pressure in the reactor 2, atm The volumetric feed rate of dicyclopentadiene, which in the reactor at high temperature (monomerized into cyclopentadiene, is 0.35 0.37 h. The reaction mass is condensed first in air and then in brine refrigerator (-10-12 ° C) The obtained organic layer is subjected to chromatographic analysis, according to which the content of norbornadiene is 24.08-27.38 wt% in individual samples depending on the reaction conditions. The organic layer is subjected to a fractionation column on a batch of with an efficiency of 30 t.t. Norbornadiene samples (tm, n 88.5-9 ° C / 76 ° mm Hg) with a content of 98-99.5 wt.% were isolated. The structure of the obtained sample of norbornadiene is proved by IR and PMR spectra.

When the reaction was carried out under the same conditions, but without the addition of water vapor, the reaction mass was obtained with a content of norbornadiene of 12.52 wt.

It is proved that in the process of obtaining NBD, abgas is approximately 97% composed of acetylene and therefore can be returned to recycling. In the proposed method, all the water vapor after the reactor is condensed in air and brine refrigerators, and abgas is also practically 97-98% acetylene, i.e. Can also be returned for recycling.

The separation of the reaction products is carried out as follows.

3590 ml of DCPD (380-400 ml / h), as well as steam (b atm) with the speed of 105-210 g / h are fed into the reactor. After the reaction, a reaction mass is obtained, which is a two-phase system with a clear interface: the upper is a light-yellow organic layer, the lower is an aqueous layer. After their separation in a separatory funnel at 20-21 ° C, 3520 ml of the organic layer (2 weight loss,%) and 1405 ml of the aqueous layer are obtained. According to the data of 5E-30 on silanivi E chromate, 0.12-0.16 mm, column 3 m 3 mm, nitrogen carrier gas 30 ml / m, chromatographic temperature 60 at a rate of 25 C / min, LHM chromatograph 8 MDS FID (Conversion DCPD, taking into account its monomerized form, the CPD is 31%.

Get the composition of the organic layer containing, wt.%:

Cyclopentadiene 19.73

Claims (2)

Norbornadiene27,1 Toluene 0.12 Cycloheptaterien 2.73 Dicyclopentadiene 43.18 Dienomethylenehexahydronaphthalene 1.6 Unidentified high boiling 5.54 The organic layer is subjected to a phonic separation by a batch of 30% e.p. From 3223 G (259Q) of the reaction mass, the following is obtained: Fraction 1Ц1Д 628.6 g from boiling points 40-88 С ЩЩ 72.4% / 760 mm НБД 18.8% Toluene 0.23% Cycloheptatry, en8.57% Fraction of commodity norbornadium 522.65 g, with a boiling point of 88.91 C / 760 mm Hg. CPD0.96% NBD. 97.19% Toluene 0.26% Cycloheptatriene 1.59% VAT residue 1180.85 g NBD0.32% Cycloheptatriene 0.11% DCPD87.22% Dyandomethylene hexahydronaphthalene 3.68% Unidentified: 8687% high boiling baths After additional rectification of the product NBD on the column are filled with NBD samples (ki temperature is 88.5-90 0/760 Hg) with a NBD yield of 98-99.5 wt.%. From the cube of it, the ostytka is recovered by returning D1SPD. At a top temperature of 85-90 / 50 mm Hg. with the content of the main product in the samples 95-97%. The composition of the aqueous layer and the regeneration of water vapor. The pH is determined in the aqueous layer as well as spectrophotocolorimetrically phenols, organic acids and carbonyl compounds: pH Phenols (0.003 wt.% By nitration reaction of p-nitroaniline). Organic acid, 0069 wt.% (By way of conversion into hydroxamic acids7 Carbonyl, 3 wt.% (By transferring water to hydroeon)) Purification of this water is performed by neutralizing acidic impurities and adjusting the pH to 7-8, followed by evaporation in a steam generator. in pairs 6,12 and 21 atm (according to need. Claim of the invention. Method of obtaining norbornadiene by interaction of cyclopentadiene or its dimer with acetylene at elevated temperature and pressure in the presence of a phlegmatizer, characterized in that, in order to simplify the process technology, The phlegmatizer uses water vapor and the process is carried out at a molar ratio of cyclopentadiene: acetylene: water, equal to 1: {1.05-1.1} ..; U-2) at 370-38 ° C and pressure 2.8 3 Sources of information, taken into account during the examination 1. M. Nishnikova A., et al. Preparation of bicyclo (2.2.1 | -heptadiene-2, 5 by condensation of cyclopentadien with acetylene without the use of a phlegmatizer. Izv. AN SSSR Ser. Chem., 1967 5, pp. 1127. - / 2. Glikin M.A. et al. Phlegmatization of acetylene by cyclopentadiene. Petrochemistry, VI, 1966, No. 1, p. 101 (prototype).