Phillips has your

Sulfur Chemical Mercaptans

Ethyl mercaptan η-Propyl mercaptan iso-Propyl mercaptan η-Butyl mercaptan sec-Butyl mercaptan iso-Butyl mercaptan tert-Butyl mercaptan n-Hexyl mercaptan Cyclohexyl mercaptan n-Octyl mercaptan tert-Octyl mercaptan tert-Nonyl mercaptan n-Dodecyl mercaptan tert-Dodecyl mercaptan tert-Tetradecyl mercaptan tert-Hexadecyl mercaptan tert-Mixed mercaptans

(C», C12) (C12, C14, L i e )

2-Mercaptoethanol Benzyl mercaptan

Sulfides Ethylthioethanol Di-n-butyl sulfide Di-tert-butyl sulfide Ethylthioacetate Phenylthioethanol

Disulfides Di-tert-butyl disulfide Di-tert-dodecyl disulfide Di-n-butyl disulfide

Polysulfides Di-tert-butyl polysulfide

Sulfones Sulfolane (anhydrous) Sulfolane-W Sulfolene

New Developmental Sulfur Chemicals From Phillips: We can now produce developmental to commercial quanti­ties of Di-n-propyl and Di-sec-butyl disulfides, Ethanedithiol, Thiodiglycol and Di-tert-nonylpolysulfide.

PHILLIPS CHEMICAL COMPANY A SUBSIDIARY OF PHILLIPS PETROLEUM COMPANY

Science

smaller molecules, the signals from the hemoglobin protons have decayed completely by the time the spectrum is taken. The result, Rabenstein says, is an NMR spectrum with observable peaks from a number of molecules including glucose-free glycine, ala­nine, and glutathione.

Rabenstein uses two peaks from glutathione to study the binding of methylmercury in red blood cells and how various drugs affect that binding. Methylmercury is highly toxic. Ac­cording to Rabenstein, about 10% of the body burden of methylmercury is in the blood and, of that, about 90% is in the red blood cells. Glutathione is an amino acid with a sulfhydryl group that forms a complex with methyl­mercury, and this causes a chemical shift in the resonance signal from a

proton bound to a carbon near that group.

"The rate of exchange of methyl­mercury on and off glutathione's sulfhydryl group is sufficiently rapid that there is always only one signal," Rabenstein says. "The position of that resonance is a linear function of the amount of complex formed." Rabenstein says his data show that methylmercury binds at least six times more strongly to glutathione than to hemoglobin, which also con­tains sulfhydryl groups.

By adding various compounds to "poison" red blood cells and observ­ing the effect on the resonance posi­tion, Rabenstein can evaluate the potential of the compounds as agents for treating methylmercury poison­ing. Π

Technology

Methane reforming to stay key hydrogen source Future production of hydrogen, whether for making conventional chemicals or for high-volume use as a fuel, seems limited to those processes already in existence, unless some major technological breakthrough appears. A projection by Thomas Whaley, research manager in the In­stitute of Gas Technology's energy systems department in Chicago, supports the belief that even in the beginning of the next century steam reforming of methane will remain the process of choice—with a coal-based process becoming firmly lodged in second place.

After that follow numerous spe­cialty processes that have significant, if smaller, contributions to make to hydrogen production, Whaley told the summer national meeting of the

American Institute of Chemical En­gineers in Detroit. Despite somewhat diminished enthusiasm for water splitting via nuclear-heat-driven processes, the search continues for an efficient thermochemical scheme. High-temperature steam electrolysis in a fusion reactor is the newest sug­gestion. . Catalytic steam reforming of light hydrocarbons, particularly methane, is now the least costly way of pro­ducing large volumes of hydrogen when natural gas is readily available. If higher-molecular-weight hydro­carbons are used, cost increases ac­cordingly, but is still low.

Hydrogen purity of 93% is good enough for ammonia production, the chief consumer of hydrogen at present, Whaley points out. For other

Steam reforming is cheapest route to hydrogen

Process Feedstock/raw material cost

Steam reforming Partial oxidation

Partial oxidation Steam-irona

Electrolysis, conventional Electrolysis, solid

polymer electrolyte

Methane/$2.00 per million Btu Residual oil/$2.35 per

million Btu Coal/$1.17 per million Btu Coal/$1.00 per million Btu Water/3 cents per kWh Water/3 cents per kWh

Thermal efficiency

74% 83

59 63 76b

78b

Hydrogen cost, $ per 1000

standard cu ft

$1.61 2.69

3.66 2.56 6.83 4.45

Hydrogen cost, $ per million Btu

$ 4.76 8.23

11.20 7.84

20.90 13.62

a Includes 2 cents per kWh credit for by-product electric power, b Electric power to hydrogen (does not include the efficiencies involved in generating electricity). Note: Based on 100 million standard cu ft per day of hydrogen; 90% stream factor. Source: Institute of Gas Technology

Aug. 31, 1981 C&EN 39

LOOK! WHAT

CAN YOU DO WITH

THIS CHEMISTRY?

COCH,,

S-NRR

These compounds are prepared by the reaction of aliphatic and aromatic amines with our new intermediate CBC (carbo-methoxybenzene sulphonyl chloride.)

This particular chemistry suggests many useful applications in making germicides, fungicides, insecticides, and pharmaceutical intermediates, but we know there are more.

We'll provide the starting CBC, our manufacturing know-how and/or facil­ities to produce your derivative. (You provide the imagination.)

Initial development quantities of CBC are immediately available.

Phone or write: R. Carr, Sherwin-Williams Company, Chemicals Division, 501 Murray Road, St. Bernard, Cincinnati, Ohio 45217 (513) 242-3300. Cable "Sherwin" Cleveland, Intelex 985675

CHEMICALS ©1981 -The Sherwin-Williams Company

Technology

applications, higher purity is re­quired.

Whaley says that partial oxidation of coal and/or heavier liquids is somewhat comparable, and with conventional processing, hydrogen purities of up to 99% are possible. Even here, much of the hydrogen comes from water via the shift reac­tion, because coal, in particular, is hydrogen deficient.

Other processes for hydrogen pro­duction become progressively more exotic. For producing very pure hy­drogen in small quantities, reaction of metals and metal hydrides with water or acids can be used. The only other high-volume process of commercial interest is the steam-iron process, but this process isn't considered viable without a way to regenerate pure iron.

Electrolysis of water is probably the oldest way to make hydrogen, but in the U.S. only about 1% of the hy­drogen consumed is produced elec-trolytically, says Whaley. Even so, there are some rather large electrol­ysis plants where hydroelectric power is available. The most advanced electrolysis plant now being tested uses solid polymer electrolyte, which selectively transports hydrogen ions to an anode where molecular hydro­gen is generated.

Much attention has been given to thermochemical and hybrid ther-moelectrochemical cycles. Most are complex and require a high-temper­ature heat source for operation. Heat sources frequently mentioned are nuclear reactors, which often do not have high enough temperatures, and solar furnaces, which usually are plagued by low flux. The most studied thermochemical cycles, according to Whaley, involve sulfur com­pounds—which add high-tempera­ture corrosion to the list of problems. At IGT, Whaley and his associates recently have demonstrated hydrogen production from a cadmium-based cycle using solar heat. However, so far none of the multireaction cycles have been scaled up to a pilot plant and any economic projections of processes involving thermochemical cycles are speculative at best.

One of the latest thermochemical cycles to be suggested was described at the AIChE meeting by consultant William H. Dorrance of Organization Control Services, Ann Arbor, Mich., who has reduced the number of re­actions in such a cycle to two. He suggests using oxidation-reduction reactions in zeolite hosts that would appear to operate at near the Carnot efficiency limit. For thermodynamic

reasons, water splitting with ther­mochemical cycles requires high-temperature heat, and the main thrust of the search for effective cy­cles has been to lower the required maximum temperature.

Of the many zeolites known, Dor­rance suggests initial trials with mordenite loaded with a suitable ox­idation-reduction cation pair, such as chromium-indium or bi- and trivalent europium. A crucial problem with this scheme would be the high-flux heat transfer required in the solid phase within the zeolite beds.

At present, Whaley estimates, water photolysis is being investigated in about 50 research laboratories around the world. The idea in pho-tolytic processes is for a semicon­ductor to absorb light of certain wavelengths, which in turn photoe-lectrolyzes the water with which it is in contact. Oxygen and hydrogen are thereby produced. The concept is too new, however, to permit analysis of economic or technical feasibility.

Still another new process that has been suggested is electrolysis of steam in solid electrolyzer tubes heated with neutrons in a fusion reactor to tem­peratures of 1500 °C. The projected efficiency of such a process is 60%, but little work has been done on it. D

Lab optimizes burning of hazardous wastes A new thermal destruction laboratory has gone into operation at Midwest Research Institute, Kansas City, Mo. The bench-scale facility, which can accommodate gram quantities of hazardous wastes in liquid, slurry, or solid forms, is used to determine op­timum conditions for incineration and also to confirm the effectiveness of the incineration procedure.

MRI notes that incineration of hazardous wastes has become more complicated as a result of new Envi­ronmental Protection Agency regu­lations. These regulations establish a permit system for operators of haz­ardous waste incinerators. They set forth strict performance and proce­dural standards, including 99.99% destruction and removal efficiency for specified "principal organic hazard­ous components." They specify that "trial burns" be carried out before full-scale incineration of "new" wastes. And they require appropriate evidence that standards and permit conditions are being met.

According to Douglas E. Fiscus, head of MRFs applied science sec-

40 C&ENAug. 31, 1981