SU1490107A1 - Method of producing aloocymene - Google Patents

Abstract

The invention relates to the production of hydrocarbons, in particular, to a method for producing alloocimene (2,6-dimethyloct-2,4,6-triene), used for the production of fragrances, varnishes, resins. The goal is to increase the yield of allocimene and increase productivity, reduce energy costs and simplify plant maintenance. The Α-pinene isomerization process is first carried out in a heated reactor at 390-460 ° C and a reaction time of 0.3 s, then in an unheated tubular reactor at 1.2-1.3 s and an outlet temperature of 320-370 ° C. These conditions make it possible to increase the yield of allo мена omene from 23–43.1 to 49 wt.% Based on the initial Α-pinene (more than 6 times) and, accordingly, increase the removal of the product and energy consumption per unit surface of the heated reactor. The process is simplified by preventing the formation of solid coke deposits on the walls of the reactor, which in a known method must be scraped off, and in the proposed resin is drained in hot form from the bottom of the second reactor. 1 tab.

Description

The invention relates to the production of unsaturated hydrocarbons, namely, alloocimene (2,6-dimethyloct-2,4,6-triene), used to manufacture various chemical products, such as fragrances, varnishes, resins, etc.

The purpose of the invention is to increase the yield of aJ7Lootsimen by increasing the removal of the product per unit surface of the heated reactor and simplifying the process technology by reducing energy costs and reducing the cost of maintaining the plant.

The invention is illustrated by the following examples.

Example 1 (comparative). The installation includes the following apparatuses: an evaporator, a vapor superheater, a reactor (pyrolyzer) and a refrigerator. The reactor with a volume of 3.56 dm and a heating surface of 1.24 m is an apparatus with a ring-shaped reaction channel, the length of the pipes is 6 m, the internal diameter is 66 mm.

The reactor operates under the following conditions:

Parop temperature at the reactor inlet, ° C 290-330 Vapor temperature at the reactor exit (and at the fridge inlet), C 420-440 Raw materials contain 88 wt.% Cf-millet. The optimal feed rate is 60-70 l / h.

Under these conditions, a pyrolyzate containing 38% by weight of alloocimene and 0.5% by weight of c-pinene is obtained. The yield of alloocene is 43.1% by weight,

EXAMPLE 2 Unlike Example 1, the installation. In addition to the heated reactor, it includes a 15 dm unheated reactor, which is a tubular heat exchanger.

In the first heated reactor, o-pinene vapors, coming from a superheater with a temperature of 290-330 ° C, are quickly heated to 420-440 ° C. Here, the isomerization begins, but does not reach the end (the conversion from (the pinane at the exit from the first reactor is 60-80%). In the second unheated reactor, the isomerization is continued due to the heat accumulated in the first reactor and ends with a gradual decrease temperatures up to 340-350 C.

The feedstock contains 88% by weight of c-pine. The optimal feed rate is 120-130 l / h.

The pyrolyzate obtained under these conditions contains 43.2% by weight of alloozymene and 0.7% by weight of o / -pinene.

The pyrolyzate contains significant amounts of dipentene, isomeric pyrenens and degradation products, impurities of the initial c / -pinene and products of their transformation. The output of allootsimene 49.1 wt.%.

Examples 3-10 illustrate the dependence of the allo-omene yield on the temperature of the vapors leaving the heated and unheated reactors (limiting and transcendent values of the stated parameters). The installation operates under the conditions of Example 2. Exodus

This raw material contains 85% by weight of non-nitrogen.

The results of examples 1-10 in comparison with the known method are shown in the table.

Thus, the proposed method allows to increase the yield of alloocimene from 23-43.1 to 49 wt.% Based on the initial o-pinene, more than 6-fold increase in the removal of the product per unit surface of the heated reactor.

Labor costs for servicing the pyrolyzer are reduced due to

reduction of coke formation. Coke formation is reduced due to the fact that a product containing not

more than 80% allootsiemena - the main source of coke. In addition, the contact time is reduced.

The heated reactor of the experimental unit, which was operated according to the proposed method under the conditions of Example 2, worked for more than half a year without stopping for cleaning. The control opening of the reactor through this period showed that its walls

covered only by a thin bloom of dry carbonaceous deposits. No formation of coke and tar was detected. The deposition of small amounts of resin (20-50 g per 1 ton of pyrolysate) is noted in the second Unheated Reactor. Due to the fact that the walls of this reactor are not overheated, the gum produced does not undergo further conversion to coke. To remove it, it is periodically drained in hot form from the bottom

parts of the reactor.

Claims (1)

Invention Formula The method of producing alloocimene, which includes thermal isomerization of o (pinene in a heated reactor, characterized in that, in order to increase the yield of the target product and simplify the process technology, isomerization is first carried out in a heated reactor at an inlet temperature of 200-350 ° C in the heated reactor, at the output of 400-450 s, and the process is completed in an unheated reactor at an outlet temperature of 320-370 ° C. In examples 1, 2 - based on ft (-mifl s'Anl "(-tten, w other examples - calculation on 85X-R cost of ct-mmeH.