Solubility of RDX

The different solubilities of HMX and RDX in organic solvents means that pure HMX is easily isolated from RDX-HMX mixtures the higher solubility of RDX in acetone means that recrystallization of such mixtures from hot acetone yields pure HMX. ... 

This test is based on the formation of AN on hydrolysis with a mineral acid. HMX and other nitramines, such as Tetryl and ammonium salts interfere. However, Tetryl may be removed before the test with benzene (solubility of RDX is only 0.05%) and ammonium salts with water... 

RDX has a vapor pressure of 1.0 10" mm Hg (Army 1987a). It may exist in both the vapor phase and particulate phase in the atmosphere (Eisenreich et al. 1981). The solubility of RDX in water is low to negligible (Merck 1989 HSDB 1994). However, the following water solubility values have been reported 21.8-21.9 mg/L at 10 °C, 38.4-38.9 mg/L at 20 °C, and 66.7-67 mg/Lat30 °C(Army 1983b). RDX is slightly soluble in methanol, ether ethyl acetate, and glacial acetic acid (Merck 1989). The Henry s law constant for RDX (1.2 10" atm-m 3/mol) (McKone and Layton 1986) indicates that RDX tends to partition equally between the atmosphere and water (Eisenreich et al. 1981) and that volatilization is a slow transport process (Lyman et al. 1982). 

The eutectic mixture is 4.16 percent RDX at 79°C. Table 8-18 lists the solubility of RDX in various solvents. There is considerable divergence in the solubility data for RDX taken from different sources in the literature, probably due to the different methods and conditions used in making the determinations, the difference in purity, and the difference in physical state of the RDX tested. 

The simplest method of preparing RDX (7.9) is by adding hexamethylenetetramine to excess concentrated nitric acid at 25 °C and warming to 55 °C. RDX is precipitated with cold water and the mixture is then boiled to remove any soluble impurities. Purification of RDX is carried out by recrystallization from acetone. 

Sitzmann and Foti (Ref 2) detd the approx solubilities of representative expls (RDX, HMX, HNS, DATB, etc) in various solvents in a search for a general solvent for expls. This work was occasioned by the use in recent years of new... 

The following tables 3,4,5 and 6 (from Ref 2) detail the approx solubility (after 5 minutes of stirring at temps ranging from 25° to 95°) of RDX, HMX, HNS and DATB per lOOg of candidate solvents ... 

H2S or HI, so as to form lead carbonate, sulfide or iodide ortiy on the surface without penetration into the crystal (Ref 22). This treatment will unquestionably reduce the efficiency of LA because it will be contaminated by inert materials l)Solubility of LA in water or in 50% alcohol was detd as described in item VII F under Lead Azide Plant Analytical Procedures In addn to above listed tests, the various LA s were loaded in M47 caps as intermediate chges together with NOL No 130 as a primary chge and RDX as a base chge and subjected to the following tests given in the Purchase Description PA-PD-202, with Rev 1 dated 30 Sept 1952 and Amend 1 dated 27 Jan 1953 ... 

HMX has similar properties of RDX with respect to the chemical reactivity and solubility in organic solvent. HMX is superior to RDX as an explosive because of its high ignition temperatime and chemical stability. The disadvantage of HMX compared to RDX is reflected in its lower explosive power [4, 6,]. 

In the presence of RDX the quantitative determination of HMX is by the formation of the stable complex of HMX with dimethylformamide insoluble in CCI4. Another method consists in the separation of HMX by low solubility in J,2-dichloroethane. For detailed description of the methods see the Encyclopedia (127). 

Very low solubility of HMX (as compared with RDX) makes experiments on toxicity of the compounds less conclusive than with RDX. So far it appears that HMX is less toxic than RDX (1). 

RDX was shown to be inactive in the UDS in WI-38 human fibroblasts, with and without S9 metabolic activation [47], Reported test concentrations were in the range of 250 to 4000 pg ml-1, well over the aqueous solubility of the compound (approximately 70 pg ml-1) [48], Similarly, in the HGPRT-V79 assay with or without metabolic activation, both RDX and HMX were inefficient in inducing 6-thioguanine resistant cells. The test concentrations used were up to 40 pg ml1 for RDX and 10 pg ml-1 for HMX, close to the solubility limit of these compounds in water [2], Another confirmation of the lack of mutagenic activity of RDX was provided recently when the compound was found inactive in the mouse lymphoma forward mutation assay using the L5178Y cell line [49],... 

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