Title of Invention

A PROCESS FOR SEPARATING UNDESIRED COMPONENTS FROM A BUTYNE DIOL SOLUTION

Abstract

A process for separating undesired components, such as acetylene, formaldehyde, propargyl alcohol or the like, of the crude butyne diol solution withdrawn from the butyne diol synthesis, where the undesired components are separated from the crude butyne diol solution by means of super heated steam stripping. The water vapour supplied to the superheated steam stripping has a temperature between 105 and 140°C and a pressure between 1.2 and 1.5 bar. PRICE: THIRTY RUPEES.

Full Text

The invention relates to a process for separating undesired components, such as acetylene, formaldehyde, propargyl al¬cohol or the like, of the crude butyne diol solution with¬drawn from the butyne diol synthesis. The crude butyne diol solution withdrawn from the butyne diol synthesis still contains physically dissolved acety¬lene, unreacted formaldehyde, propargyl alcohol as well as further low- and high-boiling components. It is known to remove acetylene by means of a stripping column, and then to supply the crude butyne diol solution to two vacuum dis¬tillation columns arranged one behind the other. In the first vacuum distillation column formaldehyde and low-boil¬ing components are removed from the crude butyne diol solu¬tion, whereas in the second vacuum distillation column the high-boiling components are separated, and the pure butyne diol solution is withdrawn at the top (see for instance Chem System Inc., Butanediol/Tetrahydrofuran-Report, No. 91S15, April 1993, page 22, Fig. II.B.l). The separation of the above-mentioned undesired constituents from the crude butyne diol solution is necessary, as acetylene and formal¬dehyde would otherwise lead to an increased formation of byproducts in the subsequent hydrogenation reactor and thus impair product quality and yield. In addition, the catalyst activity would be reduced. The object of the invention is to separate undesired compo¬nents in a single separation process. In accordance with the invention this is achieved in that the undesired components are separated from the crude bu¬tyne diol solution by means of superheated steam stripping. By means of superheated steam stripping it is now possible to separate the undesired components from the crude butyne diol solution in a single column. This results in several advantages. The vacuum distillation used in the known pro¬cess for separating the formaldehyde leads to the fact that the crude butyne diol solution, from which the formaldehyde has been removed, becomes almost anhydrous at the bottom of the first vacuum distillation column. The boiling of the crude butyne diol solution leads to an increased formation of high-boiling components. The content of high-boiling components disturbing the hydrogenation is thus increased to such an extent that, as has already been mentioned above, the same must be separated in an additional vacuum distillation column. The overhead distillation of butyne diol, however, leads to a considerable risk of accidents, which exists when there is a spontaneous decay of the crude butyne diol solution. The critical bottom temperature of the distillation column is about 150°C. In the process in accordance with.the invention, however, the water content of the crude butyne diol solution remains almost constant. Accordingly, there is no boiling of an anhydrous butyne diol solution, as this is the case in the prior art pro¬cess. A spontaneous decay can therefore not occur. In addi¬tion, the crude butyne diol solution undergoes a more care¬ful treatment than this is the case in the thermal distil¬lation, which is also due to the shorter dwell times in the steam stripping column. The invention as well as a special embodiment thereof will -the acccompanying drawings, in which now be explained in detail with reference to/\Fig. 1 and the ' subsequent Table. The concentrations of the individual com¬ponents are indicated in mole-%. Table 1 The crude butyne diol solution is supplied to steam stripping column K via line 1 with a pressure of 1.3 bar and a temperature of approx. 105°C. Column K is furthermore charged via line 2 with superheated steam at a pressure of 1.3 bar and a tempera¬ture of 140°C. The temperature of the supplied steam can range between 105 and 140°C, whereas the pressure preferably lies in the range between 1.2 and 1.5 bar. The butyne diol solution withdrawn via line 3 only contains approx. 0.5 mole-% formalde¬hyde. For adjusting this residual quantity of formaldehyde ap¬prox. 1.5 kg/h steam are required for lkg/h crude butyne diol solution. The residual formaldehyde content can be reduced by higher steam quantities up to the formaldehyde detection limit, i.e. to about the 100 ppm region. Via line 5 acetylene is with¬drawn at the top of steam stripping column K, whereas via line 6 formaldehyde, water and low-boiling components such as propargyl alcohol are withdrawn. The butyne diol solution withdrawn via line 3 can now be supplied either directly to a subsequent hy-drogenation unit (not shown) or first to a unit for separating high-boiling components and then to the hydrogenation unit. In summary it can be noted that with the process in accordance with the invention at least one column can be saved as against the known process. The superheated steam stripping not only com¬bines the stripping step and the first distillation step of the known process, but can possibly, in accordance with the selected parameters or depending on the composition of the crude butyne diol solution supplied to the superheated steam stripping unit, also do without the second distillation step, which serves the separation of high-boiling components. 1. A process for separating undesired components such as acetylene, formaldehyde, propargyl alcohol or the like from the crude butyne diol solution withdrawn from the butyne diol synthesis, characterized in that the un¬ desired components are separated from the crude butyne diol solution by means of superheated steam stripping. 2. The process as claimed in claim 1, characterized in that the steam supplied to the superheated steam stripping has a temperature between 105 and 140°C and a pressure between 1.2 and 1.5 bar. 3. A process for separating undesired components such as acetylene, formaldehyde or the like from the crude butyne diol, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

1039-mas-1995 abstract.pdf

1039-mas-1995 assignment.pdf

1039-mas-1995 claims.pdf

1039-mas-1995 correspondence-others.pdf

1039-mas-1995 correspondence-po.pdf

1039-mas-1995 description (complete).pdf

1039-mas-1995 drawings.pdf

1039-mas-1995 form-1.pdf

1039-mas-1995 form-26.pdf

1039-mas-1995 form-4.pdf

1039-mas-1995 form-6.pdf

1039-mas-1995 form-9.pdf

1039-mas-1995 petition.pdf