Abstract: Multitube falling film reactor (MTR) for continuous manufacturing of sulfonated and/or sulfated products using gaseous, diluted sulfur trioxide, (SO.sub.3(dil)) to produce surface active agents or simply surfactants, useful in the cosmetic and detergent industry. Each individual nozzle-set comprises a male part (19) and the other half (45) on the male part (10). The male part (10) forms together with the female part (19), an annular slot (21) with a constant and under all operational conditions well defined length (47), which together with a fixed opening/width determines the individual pressure drop of the said slot and thereby the individual organic flow. With this arrangement, completely homogenous distribution of organic feed is achieved without the necessity of calibration.

Abstract: The disadvantages stemming from a high content of hemicellulose in recirculated sodium hydroxide solutions used for the mercerization of cellulose in the preparation of viscose are reduced or eliminated by subjecting at least a part of the spent sodium hydroxide solution to an ultrafiltration process to remove part or all of the hemicellulose therein. The filtered sodium hydroxide liquor is supplied with make-up sodium hydroxide and is returned to the mercerization step.