Previous Page Purification of Inorganic and Metal-Organic Chemicals

367

Arsenic triiodide [50288-23-81 M 455.6, m 146O. Crystd from acetone. Arsenic I11 oxide [1327-53-31 M 197.8. Crystd from dil HCl (1:2), washed, dried and sublimed. Analytical reagent grade material is suitable for use as an analytical standard after it has been dried by heating at 105O for 1-2h or has been left in a desiccator for several hours over conc H2SO4.

3-(2-Arsenophenylazo)-4,5-dihydroxynaphthalene-2,7-disulphonicacid (trisodium salt) see Arsenazo. Aurothioglucose (gold thioglucose) [ I 2 192-57-31 M 139.2. Purified by dissolving in H20 (0.05g in lml) and ppting by adding EtOH. Yellow cryst with slight mercaptan odour. Decomposes slowly in H20, sol in propylene glycol but insol in EtOH and other common organic solvents. [FEES LE'IT 98 351 19701.

Barium

(metal) [7440-39-31 M 137.3. Cleaned by washing with ethyl ether to remove adhering paraffin, then filed in an argon-filled glove box, washed first with ethanol containing 2% conc HCI, then with dry ethanol. Dried under vacuum and stored under argon [Addison, Coldrey and Halstead JCS 3868 19621. Has also been purified by double distn under lOmm argon pressure. Barium acetate [543-80-61 M 255.4. Crystd twice from anhydrous acetic acid and dried under vacuum for 24h at looo. Barium bromate [13967-90-31 M 265.3. Crystd from hot water (20mVg). Barium bromide (2H20) [7791-28-81M 333.2. Crystd from water (lml/g) by partial evaporation in a desiccator. Barium chlorate (HzO) [13477-00-41 M 322.3. Crystd from water (1mVg) between looo and Oo Barium chloride (2H20) [10326-27-91 M 244.3. Twice crystd from water (2ml/g) and oven dried to constant weight. Barium dithionate (2H20) [ I 3 8 4 5 17-51 M 333.5. Crystd from water. Barium ferrocyanide (6H2O) [13821-06-2] M 594.8. Crystd from hot water (100mUg). Barium fluoride [7787-32-81 M 175.3, m 1353O, b 2260°, d 4.83. Washed well with distd H20 and dried in vacuum Sol in H20 [ 1.6g (loo), 1.6g (20O) and 1.62g(3Oo) per L), mineral acids and aq NH4Cl. May be stored in glass bottles. [Handbook of Preparative Inorganic Chemistry (ed Erauer) Vol I 234 19631. Barium formate [541-43-51 M 277.4. Crystd from warm water (4ml/g) by adding EtOH and cooling. Barium hydroxide (8H2O) [12230-71-61 M 315.5, m 78O. Crystd from water (lml/g). Barium hypophosphite (H20)[14871-79-51 M 285.4. Ppted from aq soln (3ml/g) by adding EtOH. Barium iodate (H20) [10567-69-81 M 505.2. Crystd from a large volume of hot water by cooling. Barium iodide (2H20) [7787-33-91 M 427.2. Crystd from water (0.5ml/g) by partial evapn i n a desiccator Barium ionophore I [N,N,N',N'-tetracyclohexyloxy-bis-(o-phenyleneoxy)diacetamide] [96476-01-61 M 644.9, m 156-158O. Purified by chromatography on a Kieselgel column and eluted with

368

Purification of Inorganic and Metal-Organic Chemicals

CH2Cl2-EtOAc (5:1), and recryst from EtOH-Me2CO as colourless crystals. It is an electrically neutral ionophore with high selectivity for Ba++ions and with high lipophilicity. [ B 118 1071 19851.

Barium manganate [7787-35-11 M 256.3. Wash with conductivity H 2 0 by decantation until the supernatant gives a faint test for Ba++. Remove excess H20 in vac (IMPORTANT), then heat at 100° and the last traces of H20 are removed in a vac desiccator over P2O5. Store over KOH. It disproportionates in hot H20 or dil acid to Ba(MnO2)2 and MnO2, and is a mild oxidant. [JAG'S 44 1965 1924; lnorg Synfh 11 56 19601. Barium nitrate [10022-31-81 M 261.4, m 593O(dec). Crystd twice from water (4ml/g) and dried overnight at 1 1Oo. Barium nitrite (H20) [7787-38-41 M 247.4. Crystd from water (lml/g) by cooling in an ice-salt bath. Barium perchlorate [13465-95-71 M 336.2, m 5 0 5 O . Crystd twice from water. Barium propionate (H2O) [5908-77-01 M 301.5. Crystd from warm water (50ml/g) by adding EtOH and cooling. Barium sulphate [7722-43-71 M 233.4. Washed five times by decantation with hot distilled water, dialysed against distd water for one week, then freeze-dried and oven dried at 105O for 12h. Barium tetrathionate [82203-66-51 M 361.6. Purified by dissolution in a small volume of water and ppted with EtOH below 5 O . After drying the salt was stored in the dark at Oo. Barium thiocyanate (2 H20) [2092-17-31 M 289.6. evaporation in a desiccator.

Crystd from water (2.5ml/g) by partial

Barium thiosulphate [35112-53-91 M 249.5. Very slightly soluble in water. Washed repeatedly with chilled water and dried in air at 40°. Benzenearsonic acid see Phenylarsonic acid. Benzenechromium tricarbonyl [12082-08-51 M 214.1. m 163-166O. Purified by sublimation in vacuo. Benzenephosphinic acid [ I 779-48-21 M 142.1, m ca 70°. Purified by allowing to stand for several days under ethyl ether, with intermittent shaking and several changes of solvent. After filtration, the excess ether was removed in vacuum. Benzeneseleninic acid [6996-92-51 M 189.1, m 123-124O. Recrystd twice from water [Kice and Purkiss JOC 52 3448 19871. Benzenestibonic acid (535-46-61 M 248.9, m >250°(dec). Crystd from acetic acid, or from EtOHCHC13 mixture by addition of water. Benzyltriphenylphosphonium chloride [1100-88-51 M 388.9, m 280° (sintering), 287-288O. Wash with Et2O and crystallise from EtOH (six sided plates). Hygroscopic and forms crystals with one mol HzO. [A 229 320 1885; B 83 291 19501.

Beryllium acetate (basic) [543-81-71 M 406.3, m 285-286O. Crystd from chloroform. Beryllium potassium fluoride [7787-50-01 M 105.1. Crystd from hot water (25ml/g). Beryllium sulphate (4H20) [7787-56-61 M 177.1. Crystd from weak aqueous H2SO4.

Purification of Inorganic and Metal-Organic Chemicals

369

Bicyclo[2.2.l]hepta-2,5-diene rhodium (I) chloride dimer (norbornadiene rhodium chloride complex dimer) [12257-42-01 M 462, m 240°(dec). Recrystd from hot CHCl3-pet ether as fine crystals soluble in CHC13 and C6H6 but almost insoluble in Et20 or pet ether. [JCS 3178 19591. 2-Biphenylyl diphenyl phosphate [132-29-6J M 302.4, n251.5925. Vacuum distd, then percolated through an alumina column. Passed through a packed column maintained at 150° to remove residual traces of volatile materials by a counter-current stream of nitrogen at reduced pressure. [Dobry and Keller JPC 61 1448 19571.

2,2'-Bipyridineruthenous dichloride (6H2O), see tris(2,2'-bipyridine)ruthenous dichloride. 2,2'-Bipyridinium chlorochromate [76899-34-81 M 292.6. Washed with cold conc HCl then H20 (sintered glass funnel) and dried in vacuum (CaC12) to a free flowing yellow-brown powder. Stored in the dark. [S 691 1980; SC 10 951 1980).

Bis-(p-tert-buty1phenyl)phenyl phosphate [I 15-87-71 M 438.5, b 281°/5mm, n25 1.5412. Same as for 2-biphenylyl diphenyl phosphate (above). Bis-(2-chlorophenyl) phenyl phosphate [597-80-81 M 395, b 254O/4mm, n25 1.5767. Same as for 2-biphenylyl diphenyl phosphate above.

Bis(2,9-dimethyl-l,lO-phenanthroline)copper(1) perchlorate [54816-44-51 M 579.6. Crystd from acetone.

1,l'-Bis-(dipheny1phosphino)ferrocene [12150-46-81 M 554.4, m 181-183O, 184-194O. W a s h with distilled H 2 0 and dry in a vacuum. Dissolve in ca 5 parts of hot dioxane and cool to give orange crystals m 181- 183O. Recrystn from CgHg-heptane ( 1 :2) gives product with m 183- 184O. [J Organometal Chem 27 241 19711. Bis-(2-ethylhexyl) 2-ethylhexyl phosphonate [25103-23-5J M 434.6, n25 1.4473. Purified by stirring an 0.4M soln in benzene with an equal volume of 6M HCl at ca 60° for 8h. The benzene layer was then shaken successively with equal volumes of water (twice), aqueous 5% NaZC03 (three times), and water (eight times), followed by evaporation of the benzene and dissolved water under reduced pressure at room temperature (using a rotating evacuated flask). Stored in dry, dark conditions [Peppard et al. J Znorg Nuclear Chem 24 1387 19621. Vacuum distilled, then percolated through an alumina column before finally passed through a packed column maintained at 150° where residual traces of volatile materials were removed by a counter-current stream of N2 at reduced pressure [Dobry and Keller JPC 61 1448 19571. Bis-(2-ethylhexyl) phosphoric acid [298-07- 71 M 322.4, b 209°/10mm, d 0.965. See preceding entry and Peppard, Ferraro and Mason [J lnorg Nuclear Chem 7 231 19581 or Stewart and Crandall [JACS 73 1377 19511. Bis(ethyl)titanium(IV) chloride [2247-00-91 M 177.0, Bis(ethyl)zirconium(IV) chloride [92212- 70-91 M 220.3. Crystd from boiling toluene. 2,4-Bis-( methylthi0)- 1 ,3,2h5 ,4h5-dithiadiphosphetane-2,4-dithione (Davy's reagent) [82737-61-91 M 284.4, m lao.Recrystd from C & j in yellow plates or from hot trichlorobenzene. The low m observed i n the literature (112O with gradual softening at 68-102O) has been attributed to the presence of elemental sulphur in the crystals. [TET 40 2663 1984; JOC 22 789 1957. Bismuth [7440-69-91 M 209.0, m 271-273O. Melted in an atmosphere of dry helium and filtered through dry Pyrex wool to remove any bismuth oxide present [Mayer, Yosim and Topol JPC 64 238 19601. Bismuthiol I, potassium salt [4628-94-8J M 226.4, m 275-276O(dec). Usually contaminated with disulphide. Purified by crystn from EtOH.

370

Purification of Inorganic and Metal-Organic Chemicals

Bismuth trichloride [7787-60-21 M 315.3, m 233.6O. Sublimed under high vacuum, or dried under a current of HCl gas, followed by fractional distn, once under HCl and once under argon.

z8*'

Bismuth triphenyl (triphenyl bismuth) [603-33-81 M 440.3, m 75-76O, 77-78O, 78S0, d 1.6427(melt). Dissolve in EtOH, ppte with H20, extract with Et20, dry and evaporate when the residue crystallises. It has been recrystd from EtOH and Et20-EtOH and is a stable compound. [JCS supplement p121 1949; B 37 4620 1904; JACS 62 665 1940; UV: JCP 22 1430 19541. Bis-(tetrabutylammonium) dichromate [56660-19-61 M 700.9, m 139-142O. Wash with water and dry in a vacuum. Crystallises from hexane (m 79-goo). [SC 10 75 19801.

Bis-[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphate calcium salt (Selectophore) [40835-97-01 M 987.3. The Ca diester salt is washed with H 2 0 (x3) and MeOH (x3) alternately and dried in a vacuum oven at 50". If the Ca salt is contaminated with much Ca salt of the monoester then it (log) is converted to the free acid by adding 6N HCl (ca IOvols) and Et20 (> 50vols) to it and stirred vigorously to form the free acids. When no white ppte remained (ca Smin), the Et20 is separated, washed with H 2 0 (2 x > 50 ml) and dried by filtering through a bed of anhydrous Na2S04 (1 1 x 5 cm) which is then washed with Et2O (2 x >50 ml). Evapn gives an oil (TLC RF 0.81 for diester and 0.50 for monoester). The oil is dissolved in benzene (ca 25ml) and extracted with ethane-1,2-diol (25m1, lox). After ten washings, a small sample of the benzene layer is washed twice with H20 to remove the diol and showed that it is pure bis-[4-(1,1,3,3-tetramethylbuty1)pheny1)phosphoric acid by TLC, i.e. no monophosphate. To form the Ca salt the oil is dissolved in MeOH and to it is added the equivalent amount of CaCI2together with aq NaOH to keep the pH >lo. The resulting white ppte is collected washed alternately with 3 batches of H20 and MeOH and dried in a vacuum oven at 50". [JINC 40 1483 19781.

2,4-Bis-(p-tolylthio)-1,3,2h5,4.hs-dithiadiphosphetane-2,4-dithione (Heimgartner's reagent) [I 14234-09-21 M 436.6, m 175-176O. Recrystallise from toluene(1ight yellow solid), wash with Et20 and dry in a vacuum. [HCA 70 1001 19871.

Bis-(trimethylsily1)acetylene [14630-40- 11 M 170.4, m 26", b 134-136"/atm. Dissolve in pet ether, wash with ice-cold dilute HCl. The pet ether extract is dried (MgS04), evaporated and fractionated at atmospheric pressure. [JOMC 37 45 19721. Bis-trimethylsilyl sulphide

see hexamethyldisilthiane.

Bis-(triphenylphosphine)nickel(II) chloride [14264-16-51 M 654.2. Wash with glacial AcOH and dry in a vacuum over H2S04 and KOH until AcOH is completely removed. [JCS 719 19583. Borax, see sodium borate. Boric acid [10043-35-31 M 61.8. Crystd three times from H20 (3ml/g) between 100° and Oo, after filtering through sintered glass. Dried to constant weight over metaboric acid in a desiccator. (pKa25 9.23 in H20).

9-Borabicyclo[3.3.1]nonane (9BBN) [monomer 280-64-81 [ d i m e r 70658-61-61 [I:I in tetrahydrofuran 74422-63-41 M 122.0 (monomer), 244.0(dimer), m 141-143O, 150-152O, 154-155O; b 195°/12mm. Available as the solid dimer or in tetrahydrofuran soln. The solid is relatively stable and can be purified by distn in a vacuum (as dimer) and by recrystn from tetrahydrofuran (solubility at room temp is 9.5%, 0.78M), filter solid under N2 wash with dry pentane and dry in vacua at ca 100". The solid is a dimer (IR 1567cm-'), stable in air (for ca 2 months), and can be heated for 24h at 200° in an inert atmosphere without loss of hydride activity. It is a dimer in tetrahydrofuran soln also (IR 1567cm-l). It is sensitive to H20 and air (02) in soln. Concentration in soln can be determined by reaction with MeOH and measuring the vol of H2 liberated, or it can be oxidised to cis-cyclooctane-1.5-diol( m 73.5-74.5O). [IR: JACS 90 5280 1968, 96 7765 1974; JOC 41 1778 1976,46 3978 19811.

Purification of Inorganic and Metal-Organic Chemicals

371

Borane pyridine complex [ I I 0 - 5 1 - 0 ] M 92.9, m 8-10", 10-1lo, b 86"/7mm, 100101°/12mm, d:' 0.785. Dissolve in Et20 and wash with H 2 0 in which it is insol. Evap Et20 and distil (gives better than 99.8% purity). Its vap pressure is less than O.lmm at room temp. [JACS 77 1506 19-55]. Borane triethylamine complex [ 1722-26-51 M 115.0, b 76"/4mm, 97.0°/12mm, d;' 0 . 7 8 . Distil in a vacuum using a 60cm glass helices packed column. [5.4CS 64 325 1942, 84 3407 1962; TET LE7T 4703 19681. Borane trimethylamine complex [ 75-22-91 M 73.0, m 94-94S0, b 171°/atm. Sublimed using equipment described in JACS 59 780 1937. Its vapour pressure is 86mm at looo. Colourless hexagonal crystals varying from needles to short lumps, slightly soluble in H20 (1.48% at 30°), EtOH (1%), hexane (0.74%) but very soluble in EtzO, C6H6 and AcOH. Stable at 125O. [JACS 59 780 1939,104 325 19421. Borane triphenyl

see triphenyl borane.

Boron trichloride [10294-34-51 M 117.2, b 0°/476mm. Purified (from chlorine) by passage through two mercury-filled bubblers, then fractionally distd under vacuum. In a more extensive purification the nitrobenzene addition compound is formed by passage of the gas over nitrobenzene in a vacuum system at loo. Volatile impurities are removed from the crystalline yellow solid by pumping at -20°, and the BCl3 is recovered by warming the addition compound at 50°. Passage through a trap at -78O removes entrained nitrobenzene; the BC13 finally condensing in a trap at -112O [Brown and Holmes JACS 78 2173 19561. Also purified by condensing into a trap cooled in acetonemry-ice, where it was pumped for 15min to remove volatile impurities. It was then warmed, recondensed and again pumped. Boron trifluoride [7637-07-21 M 67.8, b 111.8°/300mm. The usual impurities - bromine, BF5, HF and non-volatile fluorides - are readily separated by distn. Brown and Johannesen [JACS 72 2934 19501 passed BF3 into benzonitrile at Oo until the latter was satd. Evacuation to 10-5mm then removed all traces of SiF4 and other gaseous impurities. [A small amount of the BF3-benzonitrile addition compound sublimed and was collected in a U-tube cooled to -80°]. Pressure was raised to 20mm by admitting dry air, and the flask containing the BF3 addition compound was warmed with hot water. The BF3 evolved was passed through a -80° trap (to condense any benzonitriie) into a tube cooled in liquid air. The addition compound with anisole can also be used. For drying, BF3 can be passed through H2SO4 saturated with boric oxide. Fumes in moist air. Boron trifluoride diethyl etherate [ 1 0 9 - 6 3 -71 M 141.9, b 67O/43mm, b 126°/760mm, d 1.154, n 1.340. Treated with a small quantity of ethyl ether (to remove an excess of this component), and then distd under reduced pressure, from CaH2. Fumes in moist air. TOXIC. Bromine [7726-95-61 M 159.8, b 5 9 O , d 3.102, n 1.661. Refluxed with solid KBr and distd, dried by shaking with an equal volume of conc H2SO4, then distd. The H2SO4 treatment can be replaced by direct distn from BaO or P2O5 A more extensive purification [Hildenbrand et al. JACS 80 4129 19581 is to reflux ca 1L of bromine for l h with a mixture of 16g of Cr03 in 200ml of conc H2SO4 (to remove organic material). The bromine is distd into a clean, dry, glass-stoppered bottle, and chlorine is removed by dissolving ca 25g of freshly fused CsBr in 500ml of the bromine and standing overnight. To remove HBr and water, the bromine was then distd back and forth through a train containing alternate tubes of MgO and P2O5. HIGHLY TOXIC. Bromine pentafluoride [7789-30-21 M.174.9, m -60S0, b 41.3O, d25 2.466. Purified via its KF complex, as described for chlorine trifluoride. HIGHLY TOXIC. 2-Bromoallyltrimethylsilane [81790-10-51 M 193.2, b 64-66°/10mm, 82-85°/58-60mm, di0 1.13. Fractionally distd through an efficient column. I t is flammable. [JACS 104 3733 6879 19821.

2-Bromo-1,3,2-benzodioxaborole[ 5 1 9 0 1 - 8 5 - 0 ~M 198.8, m 47", 51-53", b 76"/9mm. Keep at 20°/15mm for some time and then fractionally distil. [JCS 1529 19591.

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Purification of Inorganic and Metal-Organic Chemicals

Bromopyrogallol Red [16574-43-91 M 576.2, E 5.45 x lo4 a t 538nm (water pH 5.6-7.5). Recrystd from aqueous alkaline s o h (Na2C03 or NaOH) by pptn on acidification [Suk Coll Czech Chem Commun 31 3127 19661. Bromosulfalein

(disodium phenoltetrabromophthalein 3',3'-disulphonate) see Chapter 3.

Bromo trimethyl silane (trimethyl bromosilane) [2857-97-81 M 153.1, m -43.5O to -43.2O; b 40S0/200mm, 77.3O/735mm, 79O/744mm, 79.8-79.9O/754mrn, d i O 1.1805, d i O 1.190, n y 1.422. Purified by repeated fractional distillation and stored in sealed ampoules in the dark. [JACS 75 1583 19531. Also fractionally distd through a 15 plate column (0.8 x 32cm packed with 1/16in single turn helices from Pt-Ir wire). [JACS 68 1161 1946; 70 433 19481. n-Butylmercuric chloride [543-63-51 M 293.1, m 130O. Crystd from EtOH. n-Butylphenyl n-butylphosphonate [36411-99-1] M 270.3. Crystd three times from hexane as its compound with uranyl nitrate. See tn-n-butyl phosphate below. p-tert-Butylphenyl diphenyl phosphate [981-40-81 M 382.4, b 261°/6mm, nZ5 1.5522. Purified by vacuum distn, and percolation through an alumina column, followed by passage through a packed column maintained at 150° to remove residual traces of volatile materials in a counter-current stream of N2 at reduced pressure [Dobry and Keller JPC61 1448 1953. Butyl phosphate see tri-n-butyl phosphate below. n-Butylstannoic acid [PhSn(OH)3] [22719-01-31 M 208.8. Purified by adding excess KOH i n CHC13 to remove n-BuSn(OH)Cl2 and n-BuSn(OH)2C1, and isolated by acidification [Holmes et al. JACS 109 1408 1983. tert-Butyldimethylsilyl chloride [ I 8 1 62-48-61 M 150.7, m 87-89O, 92S0, b 125°/760mm. Fractionally distd at atmospheric pressure. [JACS 76 1030 1954; 94 6190 19721.

Cacodylic acid

[75-60-5] M 138.0, m 195-196O. Crystd from warm EtOH (3ml/g) by cooling and filtering. Dried in vacuum desiccator over CaC12. Has also been twice recrystd from propan-2-01. [Koller and Hawkridge JACS 107 7412 19851. Cadion [ 1-(4-nitrophenyl)-3-(4-phenylazophenyl)-triazene] [5392-67-61 M 346, m 1 9 8 O . Commercial cadion is purified by recrystn from 95% EtOH and dried. It is stable in 0.2 N KOH (in 20% aqueous EtOH) at 25O. It is a sensitive reagent for Cd, and the Cd complex has hmax (EtOH) 475nm. [Australian Chem Inst J Proc 4 26 1937 ;ACA 19 377 19581. Cadmium [7440-43-91 M 112.4. Oxide has been removed by filtering the molten metal, under vacuum through quartz wool. Cadmium acetate [543-90-81 M 230.5. Crystd twice from anhydrous acetic acid and dried under vacuum for 24h at looo. Cadmium bromide (4Hz0) [7789-42-61 M 344.2. Crystd from water (0.6mVg) between and dried at 1100.

looo and Oo,

Cadmium chloride [10108-64-21 M 183.3, m 568O. Crystd from water (lml/g) by addition of EtOH and cooling.

Purification of Inorganic and Metal-Organic Chemicals

373

Cadmium fluoride [7790-79-61 M 150.4, m >lOOOo. Crystd by dissolving in water at room temperature (25mVg) and heating to 60°. Cadmium iodide [7790-80-91M 366.2, m 388O. Crystd from ethanol (2ml/g) by partial evaporation. Cadmium ionophore I [N,N,N',N'-tetramethyl-3,6-dioxooctanedi-(thioamide)][73487-00-01 M 432.7, m 35-36O. Wash well with pet ether, then several times with 2N HCl (if it has a slight odour of pyridine) then H20 and dry in a vacuum over H2S04. It is a polar selectrophore for Cd. [HCA 63 217 19801. Cadmium lactate [16039-SS-7/ M 290.6. Crystd from water (10ml/g) by partial evapn in a desiccator. Cadmium nitrate (4H20) [10022-68-11 M 308.5. Crystd from water (0.5ml/g) by cooling in ice-salt. Cadmium potassium iodide [13601-63-31 M 532.2. Crystd from ethanol by partial evapn. Cadmium salicylate [I901 0-79-81 M 248.5, Cadmium sulphate [10124-36-41 M 769.5. Crystd from distd water by partial evapn in a desiccator. Caesium compounds

see cesium compounds

Calcein [2',7'-bis-{N, N-di(carboxymethyl)aminomethyl}fluorescein] sodium salt [I461 - 1S O] M 666.5. Dissolve in distilled H20 and acidify with dilute HCI to pH 3.5. Filter off the solid acid and wash well with H20. Redissolve ca log in 300ml H20 containing 12g of NaOAc. Ppte again by adding HCl, filter and wash with H20. Add the solid to 200ml of EtOH stir for l h and filter. Repeat the EtOH wash and dry the bright yellow solid in a vacuum. This acid decomposes on heating at ca 180°. See below for the prepn of the Na salt. [AC 28 882 19561. Dissolve in H 2 0 and acidify with 3N HCl to pH 3.5. Collect the solid and wash with H20. The air-dried ppte is extracted with 70% aqueous EtOH, filtered hot and cooled slowly. Fine yellow needles of the acid crystallise out, are filtered and dissolved in the minimum quantity of 0.01N NaOH and reppted with N HCI to pH 3.5. It is then recrystd from 70% aqueous EtOH (3x). The final product (acid) is dried at SOo in a vacuum for 24h, m >300°dec. It contains one mol of water per mol of acid ( C ~ O H ~ & O ~ ~ . H The ~ O )product . is pure as revealed by electrophoresis at pH 5.6 and 8.6, and by TLC in isoBuOH-isoPrOH-AcOH-H~0(60:60:5:5 by vol) or isoPrOH or pH 8.0 borate buffer. [AC 31 456 19591. The Na salt is prepared by dissolving in H 2 0 containing 2 mols of NaOH per mol of acid reagent and lyophilizing. Calcium 17440-70-21 M 40.1, m 8 4 5 O . Cleaned by washing with ether to remove adhering paraffin, filed in an argon-filled glove box, and washed with ethanol containing 2% of conc HCl. Then washed with dry ethanol, dried in a vacuum and stored under pure argon [Addison, Coldrey and Halstead, JCS 3868 19621. Calcium acetate [62-54-41 M 158.2. Crystd from water (3ml/g) by partial evapn in a desiccator. Calcium benzoate (3H20) [2090-05-3] M 336.4. Crystd from water (lOm/g) between 90° and Oo. Calcium bromide (H20) [62648-72-01 M 217.9. Crystd from ethanol or acetone. Calcium butyrate [5743-36-21 M 248.2. Crystd from water (5ml/g) by partial evapn in a desiccator. Calcium carbamate [543-88-41 M 160.1. Crystd from aqueous ethanol Calcium chloride (anhydrous) [10043-S2-4/ M 111.0, m 772O, b >1600°, di5 2.15. Available as fused granules or cubic crystals. It is very hygroscopic. Very soluble in H 2 0 (exothermic), and EtOH. Loses H20 at 20O0 so it can be dried at high temperatures to dehydrate. Store in a tightly closed container. Calcium chloride (2H20) [22691-02-71 M 147.0. Crystd from ethanol.

374

Purification of Inorganic and Metal-Organic Chemicals

Calcium dithionite 113812-88-91 M 168.2. Crystd from water, or water followed by acetone and dried in air at room temperature.

:&

Calcium D-gluconate monohydrate [299-28-51 M 448.4, [a] + l l . O o , [a] Lo+9.O0 (c 1.2, HzO). It is sol in H20 (3.5g in lOOg at 25O). Dissolve in H20, filter and ppte by adding MeOH. Filter off solid and dry in a vacuum at 85O. Alternatively, dissolve in H20, filter (from insol inorganic Ca) and evaporate to dryness under vacuum at 85O. [J.Amer.Phann.Assoc 41 366 19521. Calcium D-heptagluconate dihydrate [17140-60-21 M 526.4, [a]a:: H20). Purified same as calcium D-gluconate.

+5.2O, [a]io+4.4O (c 5,

Calcium formate [544-17-21 M 130.1. Crystd from water (Smug) by partial evaporation in a desiccator. Calcium hexacyanoferrate (11) (11HzO) [13821-08-41 M 490.3. Recrystd three times from conductivity H20 and air dried to constant weight over partially dehydrated salt. [TFS 45 855 19491. Alternatively the Ca salt can be purified by pptn with absolute EtOH in the cold (to avoid oxidation) from an air-free saturated aqueous soln. The pure lemon yellow crystals are centrifuged, dried in a vacuum desiccator first over dry charcoal for 24h, then over partly dehydrated salt and stored in a dark glass stoppered bottle. No deterioration occurred after 18 months. No trace of Na, K or NH4 ions could be detected in the salt from the residue after decomposition of the salt with conc H2SO4. Analyses indicate 1lmols of H20 per mol of salt. The solubility in H20 is 36.45g (24.9O) and 64.7g(44.72O) per lOOg of solution. [JCS 50 19261. Calcium hydroxide [1305-62-01 M 74.1. Heat analytical grade calcium carbonate at 1000° during lh. Allow the resulting oxide to cool and add slowly to water. Heat the suspension to boiling, cool and filter through a sintered glass funnel of medium porosity (to remove soluble alkaline impurities). Dry the solid at 1loo and crush to a uniformly fine powder. Calcium iodate [7789-80-21 M 389.9. Crystd from water (lOOml/g). Calcium iodide (HzO) [71626-98-71 M 293.9. Dissolved in acetone, which was then diluted and evaporated. This drying process was repeated twice, then the CaI2 was crystd from acetone-ethyl ether and stored over P2O5. Very hygroscopic when anhydrous [Cremlyn et al. JCS 528 19581. Calcium ionophore I (ETH 1001) [58801-34-61 M 685.0. This is a neutral Ca selectophore. It can be purified by thick layer (2mm) chromatography (Kieselgel F245) and eluted with Me2CO-CHC13 (2:l). [HCA 56 1780 19731. Calcium ionophore I1 (ETH 129) [74267-27-91 M 460.7, m 153-154O. Recrystd from Me2CO. It forms 1:2 and 1:3 metamigand complexes with Mg++ and Ca++ ions respectively, and induces selectivity in membranes for Ca++ over Mg++ by a factor of ca 104. [HCA 63 191 19801. Calcium ionophore I11 [A23187 calcimycin] [52665-69- 71 M 523.6, m 181-182O, [a]? -56.0° (c 1, CHCl3). Recrystallises from Me2CO as colourless needles. Protect from light and moisture, store in a refrigerator. Soluble in Me2SO or EtOH and can be stored for 3 months without loss of activity. Mg and Ca salts are soluble in organic solvents and cross biological membranes. It has a pKa of 6.9 in 90% Me2SO. The Ca complex cryst from 50% EtOH as colourless prisms. Highly TOXIC [Annual Reviews of Biochemistry 45 501 1976; JACS 96 1932 1974, J Antibiotics 29 424 19761. Calcium isobutyrate [533-90-41 M 248.2. Crystd from water (3mUg) by partial evapn in a desiccator. Calcium lactate (5H20) [814-80-21 M308.3. Crystd from warm water (1OmUg) by cooling to Oo. Calcium nitrate (4Hz0) [13477-34-41 M 236.1, m 45O. Crystd four times from water (0.4ml/g) by cooling in a CaC12-ice freezing mixture. The tetrahydrate was dried over conc H2S04 and stored over P2O5, to give the anhydrous salt.

Purification of Inorganic and Metal-Organic Chemicals

375

Calcium nitrite (2H20) [13780-06-81 M 150.1. Crystd from hot water (1.4ml/g) by adding ethanol and cooling. 20

(+)-Calcium pantothenate (H20) [63409-48-31 M 476.5, [ a 1 5 4 6 from methanol.

+26S0 (c 5, H 2 0 ) .

Crystd

Calcium permanganate (4H20) [I0118-76-01 M 350.0. Crystd from water (3.3ml/g) by partial evapn in a desiccator. Calcium propionate [4075-81-41 M 186.2. Crystd from water (2mVg) by partial evapn in a desiccator. Calcium salicylate (2H20) [824-35-11 M 350.4. Crystd from water (3ml/g) between 90° and Oo Calcium sulphate dihydrate [IOIOI-41-41M 172.1, d2.32. Loses only part of its H20 at 100-150°. Soluble in H20 and very slowly soluble in glycerol. Insoluble in most organic solvents. Calcium sulphate hemihydrate [10034-76-11 M 145.2. Sol in H 2 0 (0.2 parts/100 at 18.75O). Completely dehydrated >650°. Dry below 300° to give a solid with estimated pore size ca 38% of vol. Anhydrous CaS04 has high affinity for H20 and will absorb 6.6% of its weight of H20 to form the hemihydrate (gypsum). It sets to a hard mass with H20, hence should be kept in a tightly sealed container. Calcium thiosulphate M 152.2. Recrystd from water below 60° in a N2 atmosphere, followed by drying with EtOH and Et20. Stored in a refrigerator. [Pethybridge and Taba JCSFT I 78 1331 19821. (4-Carbamy1phenylarsylenedithio)diacetic acid [531-72-61 M 345.1. Crystd from MeOH or EtOH. Carbonate ionophore I [ETH 60101 (heptyl-4-trifluoroacetylbenzoate) [129476-47-71 M 316.3, b 170°/0.02 Torr, d0.909. Purified by flash chromatography (2g of reagent with 30g of Silica Gel 60) and eluted with EtOAchexane (1 : 19). The fractions that absorbed at 260nm were pooled, evapd and dried at room temp (10.3 Torr). The oily residue was distd in a bubbled-tube apparatus ( 170°/0.02 Torr). Its IR (CHC13) had peaks at 1720, 1280, 940cm-* and its sol in tetrahydrofuran is 50mg/OSml. It is a lipophilic neutral ionophore selective for carbonate as well as being an optical humidity sensor. [ACA 233 41 19901. Carbon dioxide [124-38-91 M 44.0, sublimes at -78.5O. Passed over CuO wire at 800° to oxidise CO and other reducing impurities (such as H2), then over copper dispersed on Kieselguhr at 180° to remove oxygen. Drying at -78O removed water vapour. Final purification was by vacuum distn at liquid nitrogen temperature to remove non-condensable gases [Anderson, Best and Dominey JCS 3498 19621. Sulphur dioxide can be removed at 450° using silver wool combined with a plug of platinized quartz wool. Halogens are removed by using Mg, Zn or Cu, heated to 4 5 0 O . Carbon disulphide, see entry in Chapter 3. Carbon monoxide [630-08-01 M 28.0, b -191.5O. Iron carbonyl is a likely impurity in CO stored under pressure in steel tanks. It can be decomposed by passage of the gas through a hot porcelain tube at 350-400O. Passage through alkaline pyrogallol soln removes oxygen (and C02). Removal of C02 and water are effected by passage through soda-lime followed by Mg(C104)2. Carbon monoxide can be condensed and distd at -195O. HIGHY POISONOUS gas. Carbon tetrachloride, see entry in Chapter 3. Carbonyl bromide [593-95-31 M 187.8. Purified by distn from Hg and from powdered Sb to remove free bromine, then vacuum distd to remove volatile SO2 (the major impurity) [Carpenter et al. JCSFT 2 384 1973.

376

Purification of Inorganic and Metal-Organic Chemicals

Carbonyl sulphide [463-58-11 M 60.1. Purified by scrubbing through three consecutive fritted washing flasks containing conc NaOH at Oo. Then freeze-pumped repeatedly and distd through a trap packed with glass wool and cooled to - 130° (using an n-pentane slurry). Celite 545 (diatomaceous earth) [12279-49-1]. Stood overnight in conc HCl after stirring well, then washed with distilled water until neutral and free of chloride ions. Washed with methanol and dried at 50°. Ceric ammonium nitrate [16774-21-31 M 548.2. Ceric ammonium nitrate (125g) is warmed with lOOml of dilute HNO3 (1:3 v/v) and 40g of NH4N03 until dissolved, and filtered off on a sintered-glass funnel. The solid which separates on cooling in ice is filtered off on a sintered funnel (at the pump) and air is sucked through the solid for 1-2 h to remove most of the nitric acid. Finally, the solid is dried at 80-85O. Cerous acetate [537-00-81 M 317.3. Crystd twice from anhydrous acetic acid, then pumped dry under vacuum at 100° for 8h. Cesium bromide [7787-69-11 M 212.8, m 636O, b c a 1300°, d 4.44. Very soluble i n B 2 0 , soluble in EtOH but insoluble in Me2CO. Dissolve in the minimum volume of H20, filter and ppte by adding Me2CO. Filter solid and dry at looo. Also recrystd from water (0.8mVg) by partial evaporation in a desiccator. Cesium carbonate [534-17-81 M 325.8. Crystd from ethanol (IOml/g) by partial evaporation. Cesium chloride [7647-17-81 M 168.4, m 645O, b 1303O, d 3.99. Soluble in H20 but can be purified by crystn from H20 [sol in g per cent: 162.3(0.7O), 182.2(16.2O) and 290(at bp 119.4O)J and dried in high vac. Sol in EtOH and is deliquescent, keep in a tightly closed container. [Handbook of Preparative Inorganic Chemistry (ed Brauer) Vol I 951 19631. For further purification of CsCI, a conc aqueous soln of the practically pure reagent is treated with an equivalent weight if I2 and C12 bubbled into the soln until pptn of CsC12I ceased. Recrystn yields a salt which is free from other alkali metals. It is then decomposed to pure CsCl on heating. [JACS 52 3886 19301. Also rerystd from acetone-water, or from water (0.5mVg) by cooling in CaC12/ice. Dried at 7 8 O under vacuum. Cesium chromate [13454-78-91 M 381.8. Crystd from water (1.4mVg) by partial evapn i n a desiccator. Cesium fluoride [13400-13-01 M 151.9. Crystd from aqueous soln by adding ethanol. Cesium iodide [7789-17-51 M 259.8. Crystd from warm water (lml/g) by cooling to

-5O.

Cesium nitrate [7789-18-61 M 194.9. Crystd from water (0.6mUg) between 100° and Oo. Cesium oleate [31642-12-31 M 414.4. Crystd from ethyl acetate, dried in an oven at 40° and stored over p205. Cesium perchlorate [13454-84-7 M 232.4. Crystd from water (4ml/g) between 100° and Oo. Cesium perfluoro-octanoate [17125-60-91 M 546.0. Recrystd from a butanol-petroleum ether mixture, dried in an oven at 400 and stored over P2O5 under vacuum. Cesium sulphate [10294-54-91 M 361.9. Crystd from water (0.5ml/g) by adding ethanol and cooling. Chloramine-T [127-65-11 M 227.6, m 168-170°. Crystd from hot water (2ml/g). Dried in a desiccator over CaC12 (protect from sunlight). Chlorine [7782-50-51 M 70.9. Passed in succession through aqueous KMn04, dilute H2SO4, conc H2SO4, and a drying tower containing Mg(C10&. Or, washed with water, dried over P2O5 and distd from bulb to bulb. HIGHLY TOXIC.

Purification of Inorganic and Metal-Organic Chemicals

377

Chlorine trifluoride [7790-91-21 M 92.5, b 12.1O. Impurities include chloryl fluoride, chlorine dioxide and hydrogen fluoride. Passed first through two U-tubes containing NaF to remove HF, then through a series of traps in which the liquid is fractionally distd. Can be purified via the KF complex, KClF4, formed by adding excess ClF3 to solid KF in a stainless steel cylinder in a dry-box and shaking overnight. After pumping out the volatile materials, pure ClF3 is obtained by heating the bomb to 100-150° and condensing the evolved gas in a -196O trap [Schack, Dubb and Quaglino Chemistry and Industry (London))545 19671. HIGHLY TOXIC.

2-Chloro-1,3,2-benzodioxaphosphole-2-oxide see Chloro diisopropyl silane

see

1,2-phenylenephosphorochloridate.

diisopropyl chlorosilane.

4-Chloromercuribenzoic acid [59-85-8] M 357.2, m >300°. Its suspension in water is stirred with enough 1M NaOH to dissolve most of it: a small amount of insoluble matter is removed by centrifugation. The chloromercuribenzoic acid is then ppted by adding 1M HCI and centrifuged off. The pptn is repeated twice. Finally, the ppte is washed three times with distilled water (by centrifuging), then dried in a thin layer under vacuum over P2O5 [Boyer JACS 76 4331 19541. Chloromethylphosphonic acid dichloride [ 1 9 8 3 - 2 6 - 2 1 M 167.4, b 50°/0.5mm, 5253(59)O/2mm, 63-65O/3mm, 78-79O/lOrnm, 87-88O/15rnm, 102-103°/30mm, d i 0 1.638, nko 1.4971. Fractionally distd using a short Claisen column and redistd. The aniline salt has m 199-201O. The 31P NMR has a line at -38+2 ppm from 85% H3P04. [Kinnear and Perren J C S 3437 1952; NMR: J A C S 78 5715 1956; JOC22 462 19571.

2-Chloro-2-oxo-1,3,2-dioxaphospholane [6609-64-91 M 142.5, m 12-14O, b 89-91°/0.8mm, d;O1.549, n y 1.448. Should be distd at high vacuum as some polymerisation occurs on distn. It has IR bands at 3012, 2933, 1477, 1366, 1325, 1040, 924 and 858 cm-'. In H20 at looo it is hydrolysed to HOCH2CH20P03H2 in 30min [IR: Cox and Westheimer JACS 80 5441 19581. 2 - C h l ~ o p h e n y l diphenyl phosphate [I 15-85-51 M 360.7, b 236O/4rnm, n25 1.5707. Purified by vacuum distn, percolated through a column of alumina, then passed through a packed column maintained by a countercurrent stream of nitrogen at reduced pressure [Dobry and Keller J P C 61 1448 1953. Chlorosulphonic acid [7790-94-51 M 116.5, b 151-152°/750mm, d4 1.753, n 1.4929. Distd in an all-glass apparatus, taking the fraction boiling at 156-158O. Reacts EXPLOSIVELY with water.

Chloro-(2,2':6',2'-terpyridine)platinum (11) chloride (2Hz0) [60819-00-31 M 535.3. Recrystd from hot dilute HCl and cooling to give the red dihydrate. The trihydrate crysts slowly from a cold aq soln and is air dried. The red dihydrate can be obtained from the trihydrate by desiccation over conc H2SO4, by washing with EtOH or by precipitating from a warm aq soln with HCI. The dihydrate is also formed by decomposing the black trihydrate form by heating in water (slowly), or more rapidly with hot 2N HCI. [ J C S 1498 19341. Chloro-tri-isopropyl titanium [20717-86-61 M 260.6, m 45-50°, b 61-65°/0.1mm. Distd under vacuum and sets slowly to a solid on standing. Stock reagents are made by dissolving the warm liquid in pentane, toluene, Et20, THF, CH2C12,, and can be stored in pure state or in soln under dry N2 for several months. The reagent is hygroscopic and is hydrolysed by H20. [ B 118 1421 19851. Chloro trimethyl silane

see trimethyl chlorosilane.

Chloro triphenyl silane (triphenyl chlorosilane) [76-86-81 M 294.9, m 90-92O, 91-93O, 949S0, 97-99O, b 156°/lmm, 161°/0.6mm. Likely impurities are tetraphenylsilane, small amounts of hexaphenyldisiloxane and traces of triphenylsilanol. Purified by distn at 2mm, then crystd from EtOH-free CHC13, and from pet ether (b 30-60°) or hexane by cooling in a Dry-ice/acetone bath. [JCS 3671 1957; JACS 72 447 1 1958,77 6395 I955,79 1843 19571.

378

Purification of Inorganic and Metal-Organic Chemicals

Chromazurol S [1667-99-81 M 605.3. Purified by paper chromatography using n-butanol, acetic acid and water (7:3: 1). First and second spots extracted. Chromic chloride (anhydrous) [ 1 0 0 2 5 - 7 3 - 7 1 M 158.4. Sublimed in a stream of dry HCl. Alternatively, the impure chromic chloride (1OOg) was added to 1L of 10% aq K2Cr207 and several millilitres of conc HCl, and the mixture was brought to a gentle boil with constant stirring for 10 min. (This removed a reducing impurity.) The solid was separated, and washed by boiling with successive 1L lots of distilled water until the wash water no longer gave a test for chloride ion, then dried at 1 loo [Poulsen and Garner JACS 81 2615 19591.

- -

Chromionophore I [ETH 52941 [ 9 - d i e t h y I am i n o - 5 - O C t a d e c a n o y I - i m i n o - 5 H benzo[a]phenoxazine] [125829-24-51 M 583.9. Purified by flash chromatography (Silica Gel) and eluted with EtOAc. The coloured fractions are pooled, evaporated and recrystd from EtOAc. It is a lipohilic chromionophore and is a selectophore for K and Ca ions. [ A C 62 738 19901. [ 2 1 6 7 9 - 3 1 - 2 1 M 349.3, m 212-216O, 216O. Purified by Chromium (111) acetylacetonate dissolving 6g in hot C6H6 (20ml) and adding 75ml of pet ether slowly. Cool to room temp then chill on ice, filter off and dry in air to give 2.9g. Sol in heptane, C6H6 , toluene and pentane-2,4-dione at 20-40°. It forms a 1:2 complex with CHC13. [Inorg Synth 5 130 1957; J A C S 8 0 1839 19581.

Chromium ammonium sulphate (12H20) [34275- 72-41 M 478.4. Crystd from a saturated aqueous soln at 55O by cooling slowly with rapid mechanical stirring. The resulting fine crystals were filtered on a Biichner funnel, partly dried on a porous plate, then equilibrated for several months in a vacuum desiccator over crude chromium ammonium sulphate (partially dehydrated by heating at 1OOo for several hours before use)[Johnson, Hu and Horton JACS 75 3922 19531. Chromium (11) Chloride (anhydrous) [10049-05-5] M 122.9, m 824O, d i 4 2.75. Obtained from the dihydrate by heating in vucuo at 180O. It is a very hygroscopic white powder which dissolves in H20 to give a sky blue solution. Stable in dry air but oxidises rapidly in moist air and should be stored in air tight containers. It sublimes at 800° in a current of HCl gas and cooled in the presence of HCl gas. Alternatively it can be washed with air-free Et2O and dried at 1 10-1200. [Inorg Synth 3 150 19501. Chromium hexacarbonyl [13007-92-61 M 220.1, d 1.77. Wash with cold EtOH then Et20 and allow to dry in air. Alternatively recrystallise from dry Et20. This is best accomplished by placing the hexacarbonyl in a Soxhlet extractor and extracting exhaustively with dry Et20. Pure Cr(C0)6 is filtered off and dried in air. Completely colourless refracting crystals are obtained by sublimation at 40-50°/