Patent Publication Number: US-3876755-A

Title: Preparation of ammonium polythiomolbydate

Description:
United States Patent Knrtak et a].  
 PREPARATION AMMONIUM POLYTHIOMOLBYDATE Inventors: Charles R. Kurtak, Bishop. Calif;  
 Laurence D. Hartzog, Kearney.  
 Appl. No.: 370,851  
 Related U.S. Application Data Continuation-impart of Scr. No. 95.990. Dec. 7. I970. Pat. No. 3.764.649.  
 U.S. Cl. 423/517 Int. Cl. C0lb 17/98; COlg 39/00 Field of Search 423/56-58,  
 [451 Apr. 8, 1975 [56] References Cited UNITED STATES PATENTS 2.556.255 6/1951 Carosella 423/58 2.892.74l 6/1959 Spengler et al. 423/565 3.173.754 3/1965 Kurtak 423/57 3.764.649 l0/l973 Kurtak et al 423/56 Primary E.\&#39;aminerEarl C. Thomas Attorney, Agent, or FirmFrederick J. McCarthy [57] ABSTRACT I A novel composition of matter, ammonium polythiomolybdatc, having the empirical formula 3MoS .2N- H OH.  
  1 Claim, No Drawings PREPARATION OF AMMONIUM POLYTHIOMOLBYDATE This application is a continuation-in-part of US. application Ser. No. 095,990. filed Dec. 7, 1970 by C. R. Kurtak and L. D. Hartzog, now US. Pat. No. 3,764,649.  
  This invention relates to the preparation of a molybdenum compound having the empirical formula 3MoS,&#39;2NH OH and designated as ammonium polythiomolybdate.  
  It is an object of the present invention to provide a novel compound of molybdenum.  
  It is a further object of the present invention to provide a method for preparing ammonium polythiomolybdate.  
  Other objects of the present invention will be apparent from the following description and claims.  
  The novel compound, ammonium polythiomolybdate, 3MoS -2NH,OH, can be prepared by a process which comprises reacting in an ammoniacal aqueous environment, ammonium molybdate, ammonium sultide, and elemental sulfur. The reaction is conducted under pressure at elevated temperatures.  
  A novel process for producing ammonium polythiomolybdate, 3MoS 2NH OH, comprises heating under pressure an aqueous ammoniacal solution of ammonium molybdate and ammonium polysulfide (elemental sulfur dissolved in ammonium sulfide) to cause reaction therebetween and the production ofa dark red crystalline precipitate. Suitable reaction temperatures are in the range of about 175C to 220C and suitable pressures are from about 300 psig to 700 psig.  
  The above process corresponds to the following equation:  
  The aforedescribed process can be practiced by providing an ammoniacal ammonium molybdate solution by dissolving molybdic oxide, molybdic acid or other ammonium molybdate salts, e.g., ammonium paramolybdate and tetramolybdate in sufficient ammonium hydroxide. either at ambient or elevated temperatures and pressures to obtain a solution with a pH of at least about 9.0.  
  To the aforedescribed solution is added ammonium polysulfide, i.e. ammonium sulfide in which elemental sulfur is dissolved. and this reaction mixture is heated in an autoclave to a temperature in the range of 175C to 220C and maintained in this temperature range, under pressures of from 350 psig to 700 psig for from about l to 2 hours, whereby a precipitate of dark, blood-red crystalline material is obtained. This material, ammonium polythiomolybdate 3MOS,&#39;2NH,OH, is insoluble in cold water or aqueous ammonia and acetone, but is soluble in hot water or aqueous ammonia (80C) and produces therein an orange colored solutron.  
  Upon heating in air at 500C, ammonium polythiomolybdate is oxidized to M With heating in an atmosphere of hydrogen at 390C, ammonium polythiomolybdate is converted to poorly crystalline M05 at 1080C, M0 8 is formed. No other intermediate compounds are formed through this temperature range.  
  Characteristic properties of this novel compound are set forth in the following table:  
 Indices of refraction n&#39;y 2.3; na 2.2 (negative sign of elongation) diamagnetic &#34;obs.A  
 Magnetic moment X-ray Difi&#39;raction Data* (rel.)obs.**  
 bi l-mu- L86. L831 L800 L743 L692 L643 *using Copper K01 radiation observed relative intensity The following example will further illustrate the present invention.  
 EXAMPLE I Fifty (50) grams of molybdenum (as molybdic oxide) were dissolved in 500 ml of 3 Molar NH OH. The molybdic oxide employed was contaminated with tungsten and the ratio of Mo to W0 in the resulting solution was approximately 3:l. Added to this solution were 425 ml of 42 percent ammonium sulfide solution in which had been dissolved 46 grams of flowers of sulfur.  
  The foregoing reaction mixture was digested in an autoclave at 198C for 2 hours. The pressure developed in the autoclave was 350 psig. A dark, blood-red crystalline precipitate was obtained which was analyzed and found to be ammonium polythiomolybdate, 3MoS -2NH OH. The yield of molybdenum was 96.5% basedon the amount of molybdenum employed. The precipitated material was in the form of six-sided prisms (pseudo-hexagonal) with jagged bases averaging microns in length with average diameters of 15 microns.  
  When this material was roasted in air and converted to M00 the oxide product was found to have a Mo to W0 ratio of 8300zl.  
  Thus, the production of ammonium polythiomolybdate in accordance with the present invention, provides a highly selective precipitation of molybdenum from a tungsten contaminated solution.  
  A further example is provided to illustrate a novel method of producing MoS from ammonium polythiomolybdate.  
  3 4 EXAMPLE 1] X-ray Difraction Data&#34; &#34;obs.A &#39;(reL) obs.** Ten l) grams of ammonium polythiomolybdate I were heated in a tube furnace at 600 C under a hydro- 1 ()5 gen atmosphere for 2 hours. 4.85 2  
  The resulting product, when analyzed. shows the stoi- 5 chiometry of M05 X-ray diffraction shows only single 1 j phase M08 1 Surface area measurement showed 20 square meters 5&#39;8 per gram. 2.86 0.5-1.0 As shown by Example II. the novel material of the 10 present invention can be used in the production of :5 1 M05 which material is useful as a lubricant and cata- 2.45 1.0-2.0 lyst. 10-10 2.0-7.0 What is claimed is: r 2.36 2.03.0 1. As a novel composition of matter. ammonium 2.287 2.0-3.0  
 . 7 polythiomolybdate, having the formula 3MoS &#39;2N- g8: 8}? H OH and the following characteristic properties 015 16 1.94 0.54.0 1.91 0.84.2 1.895 0.54.0 20 1.863 0.5-1.0 1.831 0.5-1.0 Infrared absorption maxima 539.505 337. 278 (CM l 1.800 0.3 Specific gravity 2.57 1.743 l-Z Crystalline structure monoclinic L691 054,0 lndices of refraction n&#39;y 2.3: na 2.2 L641 0 4-9 7 (negative sign of elongation) I Magnetic moment diamugentic i i y Difraction Data* ,(reL) ohs Observed relative rnlcnslly.  
 8.76 lo 8.27 6 l=