Schmid process

The continuous method of nitroglycerine manufacture invented by A. Schmid [38] involves not only continuous nitration, but also continuous separation and washing of the product. A novel idea introduced by Schmid was the nitrator made of acid-resistant steel with mechanical stirring (Fig. 38). 

Before nitration starts, the nitrator is filled with spent add up to the level of the overflow (5). The water inlet to the cooling coils is opened, the stirrer is set in motion, and through pipes (5) and (7) fresh mixed acid is introduced to be carried off with the stream of liquid and blended with the spent acid. Mixing takes place without any notable thermal effect. Part of the liquid is recirculated via the pipe (8) and part is run through the overflow (5) to a separator. Glycerine enters through the 

For efficient operation, a steady supply of glycerine and acid at a pre-determined, constant ratio is necessary. The raw materials are delivered by means of pumps driven by a common motor and regulated in such way that a constant relation is established governing the quantity of liquid pumped. The pumps are placed in an auxiliary room above the nitration house. Further tanks for glycerine and mixed acid are located in the same room. 

Due to the high velocity of stirring and to the large cooling surface the output of this nitrator is about 10 times larger than that of conventional nitrators of the same capacity. 

An improvement to the Schmid nitrator has been introduced by Nauckhoff [25]. He replaced the cooling coils by a tubular cooler (Fig. 39). 

Nitrator for continuous nitroglycerine manufacture according to Schmid (original pattern). 

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A more recent process was developed by Biazzi and is somewhat similar in general principle to the Schmid process. It uses, however, improved chemical engineering designs and in this way is suited to operation by remote control. 

However, largely because of doubts about the safety of the innovations proposed, they have not found acceptance and it was not until 1927 when the Schmid process was devised and 1935, when the Biazzi process was developed that these continuous production processes were recognized as efficient and safe. 

In the separator for continuous separation of nitroglycerine and acid originally used in the Schmid process, certain faults were detected, which were later eliminated in a new design of 1928 (Fig. 40). 

J. Bradley, W. Stocklein and R.D. Schmid, Process Control Quality, 1 (1991) 157. U. Bilitewski and I. Rohm, Handbook of Biosensors and Electronic Noses. CRC Press, Boca Raton, 1997, pp. 435. 

Continuous methods of nitroglycerine manufacture Schmid process Washing nitroglycerine Schmid-Meissner process Raezyhski process Biazzi process... 

M. E. Frank and B. K. Schmid, "Economic Evaluation and Process Design of a Coal—Oil—Gas (COG) Refinery," paper presented at Symposium on Conceptual Plantsfor the Production of Synthetic Fuels From Coal, AIChE 65th Annual Meeting, New York, Nov. 26, 1972. 

B. K. Schmid and D. M. Jackson, "The SRC-11 Process," paper presented at Third Annual International Conference on Coal Gasification and Eiquefaction. University of Pittsburgh, Aug. 3—5, 1976 D. M. Jackson and B. K. Schmid, "Production of Distillate Fuels by SRC-11," paper presented at ACS Div. of Ind. and Eng. Chem. Symposium, Colorado Spriags, Col., Feb. 12,1979. 

The process of isolation finally adopted by the former authors consists in precipitating as reineckates the water-soluble bases contained in a methyl alcoholic extract of the curare. The mixed reineckates are further purified, by solution in acetone and precipitation with water as often as may be necessary. The product so cleaned represents the bulk of the biological activity of the crude drug the mother liquors may contain curine (p. 374), which indicates a menisperm as one of the components of such curares. The mixed reineckates are then fractionated chromato-graphically over alumina and the components isolated as chlorides by the use of silver sulphate and barium chloride in succession. This process has been modified in detail by Schmid and Karrer, who have also found that with their curare, the more soluble reineckate fraction includes less potent quaternary alkaloids. 

NG. Batch-wise production of NG is described in Vol 6, G99-102, and continuous methods such as the Schmid t-Meissner and Biazzi processes are discussed in Vol 3, C501 — 505. The Swedish injector process and the Hercules tubular nitrator will be described below, but before doing this we will discuss certain aspects of glycerin nitration that are common to both batch and continuous methods, and then contrast the main features of the batch process vs the continuous process... 

Early kinetic work127 showed that the formation of both ortho and para products was a first-order process and that the rates of reaction were insensitive to added acid or base and to change of solvent. The activation parameters were of the same order of magnitude for both reactions and the suggestion was made that both had a similar rate-determining step. Schmid et a/.128 showed that the formation of a dienone intermediate in the para rearrangement was also reversible since the radioactivity from allyl 2,6-dimethyl-4-allyl-y-14C phenyl ether LXXXVII became uniformly distributed in the y carbon atoms of the O- and C-allyl groups... 

Antes, J., Tuercke, T, Maeioth, E., Schmid, K., Krause, H., Loebbecke, S., Use of microreactors for nitration processes, in Proceedings of the 4th International Conference on Microreaction Technology, IMRET 4, 5-9 March 2000, pp. 194-200, AIChE Topical Conf. Proc., Atlanta, GA (2000). 

Kalpakjian, S., and Schmid, S.R., 2008. Manufacturing Processes for Engineering Materials, Prentice Hall, Singapore. 

Schmid, B.K. and Jackson, D.M. The SRC-II Process, Third Annual International Conference on Coal Gasification and Liquefaction, University of Pittsburgh, August 3-5, 1976. 

Held, M., Schmid, A., Kohler, H.-P. et al. (1999) An integrated process for the production of toxic catechols from toxic phenols based on a designer biocatalyst. Biotechnology and Bioengineering, 62 (6), 641-648. 

Buhler, B. and Schmid, A. (2004) Process implementation aspects for biocatalytic hydrocarbon oxyfunctiona-lization. Journal of Biotechnology, 113, 183-210. 

Beck, A (2006) Code of Practice for Organic Food Processing, (with contributions from Ursula Kretzschmar, Angelika Ploeger and Otto Schmid). Published by the Research Institute of Organic Agriculture (FiBL), Frick, Switzerland. Available as a web-publication on http //orgprints.org/7031. 

C. R. Schmid and J. D. Bryant, Chemical Process Research and Development, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285... 

Schmid, S. L. Clathrin-coated vesicle formation and protein sorting an integrated process. Annu. Rev. Biochem. 66 511-548,1997. 

Schmid, C. and L. T. Biegler. Reduced Hessian Successive Quadratic Programming for Real Time Optimization. Proceed IFAC Adv Control Chem Processes, Kyoto, Japan, 173-178 (1994). 

Figure 1.4 Number of biotransformations used catagorised by industrial sector (based on 134 processes). (Reprinted from Straathof Panke, S. and Schmid, A. The production of fine chemicals by biotransformations. Curr. Opin. Biotechnol. 2002, 13, 548-556 with permission from Elsevier.)...

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