Iron rapid crystallization method

Protoporphyrin and its derivatives, because of their labile vinyl substituents, are susceptible to acid-catalyzed hydration. For this reason aqueous solutions should be avoided in the preparation of protoporphyrin dimethyl ester from protohemin, and subsequent reinsertion of the iron. Thus the direct esterification of protohemin under basic conditions appears to be the method of choice. More stable porphyrins such as H2oep are most conveniently prepared by the direct insertion of iron(lll) ion using the iron(III) chloride method5 the resultant Fe(IIl) (oep)Cl can be separated directly from the reaction medium as shining purple crystals. However, this method fails to give successful results with protoporphyrin derivatives. In general, the iron (II) sulfate method is the mildest and should be used for all prophyrins unless one is certain that the more rapid alternatives [boiling DMF with iron(II) chloride, or preferably the more stable iron(II) perchlorate] will have no ill effect on the peripheral substituents. 

The rapid solidification methods such as the single-roU method, twin-roll method and atomization method were adopted by the patent (CN1099353A), in which the cooling rate is more than 100 K s for the rapid solidification. That is, both structure of crystal and sm-face of iron oxide are changed, and the crystallite size in a-Fe phase decreases while the amount of high active crystal face increases. Quenching... 

The modification improves performance and is interesting in connection with x-ray emission spectrography (Chapters 7, 8, and 9). It consists in measuring the intensity of tin Ka relative to that of scattered x-rays entering the detector from an analyzing crystal set for the reflection of x-rays 2.2 A in wavelength. As the tin coating becomes thicker, increased attenuation of the x-rays scattered by the iron cause s the intensity ratio to increase more rapidly than does the intensity of tin Ka. Table 6-3 contains performance data for the Quantrol on Method II (modified). The instrument can also be set up to use industrially a modification of Method III. 

The other method. of conducting the evaporation of vat liqiiors is by means of iron pans, with the fire and, heated air applied beneath. These—named fishing pans —are of considerable size, and shaped somewhat similar to a boat. They may bo heatad by a fire used solely for the purpose in which case to prevent injury to the pan, the arch of the furnace should be continued for some distance beneath, or the pan may be placed at the end of the black-ash furnace farthest from the fire, just as with the salting pan, except that the heated air is mads to pass under instead of over the pan. The evaporation is rapidly conducted by this method and when the lie becomes concentrated to a certain strength, small crystals of mo nob yd rated carbonate of soda— Na 0, COa, HO—constantly fall to the bottom, and as quickly as thoy fall are raked together to tho end of the pan farthest from the source of heat, and then Scooped or fished out by moans of perforated iron shovels. After being allowed some time to draiD, the salta so obtained are washed with fresh vat liquor, and then removed a reverberatory furnace, and all worked about until sufficiently dry. The deep-red mother liquor is either applied to the production of caustic soda or evaporated, and the residue heated with sawdust as before directed. 

The procedure is discussed in detail by Delmon et al.(82-84). The crucial step appears to be the rapid dehydration of the starting solution before any of the components can crystallize out of solution separately. Delmon(85) suggests that a rotary vacuum evaporation would be an effective method of drying the precursor. The actual structure of the precursor is not well defined, but appears to require at least one equivalent of citrate ion per mol of metal ion(83), as presumably the citrate complexes all the metal species in so Iution. The resulting powder patterns, after annealing, indicated no contamination. Delmon(J3) suggests that any multifunctional acid containing at least one carboxyl and one hydroxyl function may be effective. Experiments with tartaric acid on the iron/chromium system produced results similar to citric acid a calcination temperature of 500°C was necessary before crystallization occurred. 

Recently, a novel physical method for rapid and sensitive malaria detection in blood has been developed [46-50]. This method— ultraviolet LD MS—is based on the detection of heme (iron protoporphyrin) in blood as a qualitative and quantitative malaria biomarker, both in vitro [46] and in vivo [49,50]. In infected erythrocytes, the parasite sequesters heme from digested hemoglobin in a molecular crystal (malaria pigment or hemozoin). LDMS detects only heme from hemozoin in parasite-infected blood, and not heme, bound to hemoglobin... 

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