Akzo Nobel Chemicals International B.v.

Nouryon Chemicals International B.v.

Lars Magnus Tollin

Cornelis Kooijman

Hendrik Jan Vos

Melle Rinze Nieuwhof

Henricus Johannes Marinus Petrus Van Hal

Willem Koelewijn

Jacobus Theodorus Josef Aaldering

Jacobus Van Den Berg

Matheus Theodorus De Groot

Arie Grootenboer

The invention pertains to a method for recovering HCl from a HCl containing gas stream wherein a HCl containing gas stream with a temperature of &#x2212;20 to 25&#xb0; C. is provided to an adiabatic absorption unit where it is contacted with water as an absorbent, resulting in the formation of a top gas stream and a aqueous HCl product solution, wherein the temperature of the top gas stream is at least 70&#xb0; C. and wherein the aqueous HCl product solution has a HCl concentration in the range of 5-20 wt. %. It is preferred for the HCl-containing gas stream to be derived from a hydrogenation step wherein a feed comprising monochloroacetic acid (MCA) and dichloroacetic acid (DCA) is reacted with hydrogen to form a HCl-containing gas stream and a product stream comprising MCA and a reduced amount of DCA. The HCl product solution is preferably diluted to a concentration of 1-8 wt. %, and the diluted solution is used as absorbent in a second absorption step, wherein HCl is absorbed from a further HCl-containing gas stream to form a second aqueous HCl solution. The further HCl-containing gas stream is preferably derived from a chlorination step wherein acetic acid is reacted with chlorine, resulting in the formation of the further HCl-containing gas stream and a feed comprising monochloroacetic acid (MCA) and dichloroacetic acid (DCA).

Method for recovering HCI from a HCI containing gas stream

The present invention pertains to a process for the purification of a feed comprising monochloroacetic acid and dichloroacetic acid wherein the feed is subjected to a catalytic hydrodechlorination step by contacting it with a source of hydrogen to convert dichloroacetic acid into monochloroacetic acid in the presence of a solid heterogeneous hydrogenation catalyst comprising a Group VIII noble metal on a carrier under hydrodechlorination conditions, wherein the reaction is carried out in the presence of a catalyst enhancer which comprises a salt of a metal selected from the group of non-noble metals of Group VIII, Group VIB, Group VIIB, and Group IIB. It was found that the presence of a catalyst enhancer leads to reduced deactivation of the catalyst and/or increased activity of the spent catalyst. This allows longer production cycles, less downtime, and lower formation of side products. The catalyst enhancer preferably comprises one or more salts of one or more of nickel, cobalt, or iron, more in particular of iron. The salts preferably comprise one or more of chloride salts and acetate salts.

Process for the purification of monochloroacetic acid

The present invention is directed to a process for catalytic hydrodechlorination of dichloroacetic acid, wherein hydrogen gas is contacted with a liquid feed comprising dichloroacetic acid and monochloroacetic acid to form a product stream comprising monochloroacetic acid and an off gas stream comprising hydrogen chloride and hydrogen, and wherein the product stream is contacted with nitrogen gas so as to remove hydrogen gas present in the product stream.

Process for the hydrodechlorination of a feed comprising dichloroacetic acid

The process of the present invention pertains to a process wherein a liquid feed comprising monochloroacetic acid, dichloroacetic acid, and optionally acetic acid and/or trichloroacetic acid is subjected to a catalytic hydrodechlorination step by contacting it with a source of hydrogen in the presence of a solid heterogeneous hydrogenation catalyst situated in a fixed catalyst bed, wherein the liquid feed is fed to the top of avertical tubular reactor at a superficial mass velocity of between and 10 kg/s per square meter of the horizontal cross-section of the vertical tubular reactor and a rate of between 250 and 3,000 kg/hr per m of said catalyst bed, wherein the source of hydrogen is fed to the top or bottom of the vertical tubular reactor at a rate of between 0.025 to 0.25 Nm/s per square meter of the horizontal cross-section of the vertical tubular reactor, so as to obtain an average axial pressure gradient of at least 2 kPa per meter of said catalyst bed, and wherein the temperature in the top of the vertical tubular reactor is between 100 and 200&#xb0; C., and wherein the pressure in the top of the vertical tubular reactor is between 0.2 and 1.0 MPa.

Process for the hydrodechlorination of a liquid feed comprising dichloroacetic acid

The present invention pertains to a process for the purification of a substantially water-free liquid feed comprising monochloroacetic acid, dichloroacetic acid, optionally acid chlorides, optionally anhydrides, and optionally acetic acid, which comprises the steps of (a) adding water to the liquid feed so that a liquid feed is obtained comprising between 0.01 and 5% by weight of water, based on the total weight of the liquid feed, and (b) subsequently subjecting the liquid feed obtained in step (a) to a catalytic hydrodechlorination step by contacting it with a source of hydrogen to convert the dichloroacetic acid into monochloroacetic acid in the presence of a solid heterogeneous hydrogenation catalyst comprising one or more metals of Group VIII of the Periodic Table of the Elements deposited on a carrier.

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Skoghall, Sweden

Lars Magnus Tollin