This paper describes a method for determining the partial solubility parameters of six Methocel and six Ethocel cellulose ether products. A simple computer spreadsheet has been devised to calculate the partial solubility parameters from the laboratory data. The cellulose ethers are characterized in terms of nonpolar, polar, and hydrogen-bonding behavior. Methocel A, E, F, K, and J all have similar solubilities and are thus assigned solubility parameters in the range of 6d = 17.4-18.2, 6, = 14.6-16.5, and 6h = 15.5-19.4 in units of MPa1l2 and with a radius of interaction of 10.3. Methocel 311 has been assigned the values of 6d = 17.1, 6, = 9.8, 6 h = 13.2 MPa1/2 and a radius of interaction of 10.2. A very high methoxyl and hydroxypropyl substitution in the Methocel311 product reduces the inherent polarity and hydrogen-bonding nature of the basic cellulose structure. Increased organic-like solubility is shown by the six Ethocel ethoxy ether cellulose derivatives. The range of Hansen partial solubility parameters are nonpolar (6d) = 16.6-17.3, polar (6,) = 6.6-8.3, and hydrogen bond (6h) = 8.5-10.0 MPa1/2.

NOTES 989The following points about the chemical work are worthy of comment. 1. The addition of a small amount of acetic acid facilitated the reaction of thiosemicarbazide with the carbonyl compounds; so that it was essentially complete in one-half to one hour. Anderson, et aLI4 reported the reaction time to vary from 8 to 80 hours when no acetic acid was added. 2. The synthesis of 5-chloro-2-thenaldehyde in 50-55% yield by formylation of thiophene with N-methylformanilide was recently reported.1° It was therefore interesting to carry out the synthesis of this compound by the Sommelet procedure, in order to compare the yields by the two methods. When 5-chloro-2-methylthiophene was converted to the thenyl bromide with N-bromosuccinimide, and thence to the aldehyde, a 33y0 yield was obtained. When 2-chlorothiophene was chloromethylated by the procedure of Cairns and McKusick" and the thenyl chloride converted to the aldehyde, a 25% yield was obtained. Thus neither process is as efficient as the formylation procedure. lo Experimental Thiosemicarbaz0nes.-The general procedure for the preparation of all the thiosemicarbazones was as follows: 0.1 mole of the carbonyl compound was dissolved in 100 ml. of 50% ethanol (95% ethanol was used for the less soluble compounds) and approximately 2 ml. of glacial acetic acid and 9.1 g. (0.10 mole) of thiosemicarbazide added. The solution was warmed with occasional swirling until the thiosemicarbazide dissolved and then refluxed for approximately one hour. After cooling, the crystalline thiosemicarbazone was collected and recrystallized from 50% ethanol or methanol. The crude yields ranged from 90-96%. The thiosemicarbazones are all 'yellow crystalline compounds, but occasionally on fresh crystallization, some of them appear almost white. After drying and exposure to air, however, they assume a yellow tinge.Intermediate Carbonyl Compounds.-Although all of the thenaldehydes and acetothienones have been previously reported, some of them were prepared by methods not previously applied to these compounds and these are briefly described. 3-Thenaldehyde was prepared by the Sommelet procedure, as previously described.l2 as were 2-chloro-, 2bromo-, and 2,5-dichlor0-3-thenaldehyde.l* In the latter case, 54 g. (59%) of crude 2,5-dichloro-3-thenaldehyde was obtained from 108 g. (0.65 mole) of 2,5-dichloro-3-methylthiophene and 0.6 mole of N-bromosuccinimide, which is a considerable improvement over the yield previously reported, although no changes were made in the procedure. 5-Nitro-2-thenaldehyde was prepared by the method of Patrick and Emerson.14 The observation of Dullaghan, et aZ.,16 that this compound could not be obtained by application of the Sommelet procedure to the product obtained on treatment of 5-nitro-2-methylthiophene with N-bromosuccinimide was confirmed.5-Methyl-, 3-methyl-, 5-t-butyl-and 5-acetamido-2thenaldehyde were obtained by the dimethylformamide formylation procedure described by Campaigne and Archer .I6 The various 2-acetothienones were samples previously prepared ...

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