かって知り合いの先生が某大学の入試問題で硫黄の化学を穴埋め問題で出したが、受験生や予備校からは単なる記憶問題と猛反発を食った。それに比べ天下のT大の問題は考えさせるものが多いというのである。
しかしながら硫黄Sの示す化学種の多さには驚嘆に値するものがあるのである。出題者は工夫は少なかったがそれを狙ったのであろう。
inchem.org/documents/ehc/ehc/ehc019
Hydrogen sulfide is a colourless gas with a characteristic odour
that is soluble in various liquids including water, alcohol, ether,
and solutions of amines, alkali carbonates, and bicarbonates. It can
undergo a number of oxidation reactions to yield principal products
consisting of sulfur dioxide, sulfuric acid, or elemental sulfur.
Reaction rates and oxidation products depend on the nature of the
oxidizing agent.
The methylene blue colorimetric method has acceptable specificity,
accuracy, and sensitivity for hydrogen sulfide determinations, and is
generally recognized as a standard analytical procedure. It has been
used successfully, in automatic continuous monitoring, but
sophisticated maintenance facilities and highly trained technicians
are required for this method. Gas chromatography coupled with flame
photometric detection is an alternative method for hydrogen sulfide
determination, either as a laboratory method or for continuous
monitoring in stationary field settings.
Most of the direct-reading methods of hydrogen sulfide
determination in the occupational environment are susceptible to
various forms of interference. However, methods employing chemical
detector tubes appear to be useful in occupational settings, where
hazardous levels of hydrogen sulfide can occur. Under these
conditions, reliability and accuracy compensate for a certain lack of
specificity.
Sources of hydrogen sulfide
Hydrogen sulfide is one of the principal compounds involved in the
natural cycle of sulfur in the environment. It occurs in volcanic
gases and is produced by bacterial action during the decay of both
plant and animal protein. It can also be produced by bacteria through
the direct reduction of sulfate. Significant concentrations of
hydrogen sulfide occur in some natural gas fields and in geothermally
active areas.
Hydrogen sulfide can be formed whenever elemental sulfur or
certain sulfur-containing compounds come into contact with organic
materials at high temperatures. In industry, it is usually produced as
an undesirable by-product, though it is an important reagent or
intermediate in some processes. Hydrogen sulfide occurs as a
by-product in: the production of coke from sulfur-containing coal, the
refining of sulfur-containing crude oils, the production of carbon
disulfide, the manufacture of viscose rayon, and in the Kraft process
for producing wood pulp.
that is soluble in various liquids including water, alcohol, ether,
and solutions of amines, alkali carbonates, and bicarbonates. It can
undergo a number of oxidation reactions to yield principal products
consisting of sulfur dioxide, sulfuric acid, or elemental sulfur.
Reaction rates and oxidation products depend on the nature of the
oxidizing agent.
The methylene blue colorimetric method has acceptable specificity,
accuracy, and sensitivity for hydrogen sulfide determinations, and is
generally recognized as a standard analytical procedure. It has been
used successfully, in automatic continuous monitoring, but
sophisticated maintenance facilities and highly trained technicians
are required for this method. Gas chromatography coupled with flame
photometric detection is an alternative method for hydrogen sulfide
determination, either as a laboratory method or for continuous
monitoring in stationary field settings.
Most of the direct-reading methods of hydrogen sulfide
determination in the occupational environment are susceptible to
various forms of interference. However, methods employing chemical
detector tubes appear to be useful in occupational settings, where
hazardous levels of hydrogen sulfide can occur. Under these
conditions, reliability and accuracy compensate for a certain lack of
specificity.
Sources of hydrogen sulfide
Hydrogen sulfide is one of the principal compounds involved in the
natural cycle of sulfur in the environment. It occurs in volcanic
gases and is produced by bacterial action during the decay of both
plant and animal protein. It can also be produced by bacteria through
the direct reduction of sulfate. Significant concentrations of
hydrogen sulfide occur in some natural gas fields and in geothermally
active areas.
Hydrogen sulfide can be formed whenever elemental sulfur or
certain sulfur-containing compounds come into contact with organic
materials at high temperatures. In industry, it is usually produced as
an undesirable by-product, though it is an important reagent or
intermediate in some processes. Hydrogen sulfide occurs as a
by-product in: the production of coke from sulfur-containing coal, the
refining of sulfur-containing crude oils, the production of carbon
disulfide, the manufacture of viscose rayon, and in the Kraft process
for producing wood pulp.
Sのサイクルは窒素サイクル同様、火山、バクテリア、動物、植物の多種多様な様相を示す。工業活動による酸性雨も考慮せねばなるまい。
Sources Associated with Human Activity
There are various circumstances under which naturally occurring
hydrogen sulfide is released by human activity. For example, hydrogen
sulfide occurring in association with natural gas and/or crude oil
deposits in some areas may be released during extraction and drilling
operations. The sulfur content of crude oils ranges from 0 to 5% and
some natural gas deposits have been reported to comprise up to 42%
There are various circumstances under which naturally occurring
hydrogen sulfide is released by human activity. For example, hydrogen
sulfide occurring in association with natural gas and/or crude oil
deposits in some areas may be released during extraction and drilling
operations. The sulfur content of crude oils ranges from 0 to 5% and
some natural gas deposits have been reported to comprise up to 42%
hydrogen sulfide (Espach, 1950). Coals can contain sulfur levels of up
to 80 g/kg and, occasionally, conditions arise in which hydrogen
sulfide is formed within such deposits. Thus, special precautions must
be taken in some mining operations as well as in the drilling and
extraction of natural gas and crude oils with significant sulfur
content.
Hydrogen sulfide can also be released by activities surrounding
the development and use of geothermal resources. At the Cerro Prieto
geothermal power generating plant in Baja California, Mexico, for
example, hydrogen sulfide levels are sufficiently high to necessitate
special ventilation to protect electrical systems, and alarms for the
protection of personnel (Mercado, 1975).
During industrial operations, hydrogen sulfide can be formed
whenever elemental sulfur or certain sulfur-containing compounds come
into contact with organic materials at high temperatures. It is
usually produced as an undesirable by-product, though it is also used
as an important reagent or desirable intermediate compound in some
industrial processes such as the manufacture of sulfides, sodium
hydrosulfide, and various organic sulfur compounds. Examples of
processes in which hydrogen sulfide occurs as a by-product include the
production of coke from sulfur-containing coal, the production of
carbon disulfide, the manufacture of viscose rayon in the Kraft
process for producing wood pulp (Macaluso, 1969) and sulfur extraction
by the Frasch process.
In refining sulfur-containing crude oils, about 80%-90% of the
divalent sulfur compounds of hydrogen and carbon are converted to
hydrogen sulfide. Both the hydrogen sulfide produced and that
occurring in other industrial, geothermal, or natural gas streams can
be recovered by one of a number of processes that can be classified as
either absorption-desorption processes or processes involving
oxidation to oxides or to elemental sulfur. The bulk of hydrogen
sulfide recovered in industrial processes is used to produce elemental
sulfur or sulfuric acid (Macaluso, 1969).
Large quantities of hydrogen sulfide are used in the production of
heavy water, which is employed as a moderator in some nuclear power
reactors. The process is based on enrichment of the deuterium content
of water by hydrogen sulfide in a gas/liquid ion exchange system,
followed by separation of heavy water and water by fractional
distillation (McGraw-Hill Encyclopedia of Science and Technology,
1960).
In the tanning industry, hydrogen sulfide is produced in the
process by which hair or wool is removed from the hides. This
typically involves deliming by adding ammonium chloride or ammonium
sulfate followed by pickling with sulfuric acid, and takes place in
large rotating drums. The gases evolved, including hydrogen sulfide,
are released from the drums on opening the hatches either to add
chemicals or to unload the treated hides, and also from the waste
waters (ILO, 1971).
As in the natural environment, hydrogen sulfide can be generated
by bacterial action in industrial or community settings in malodorous
and sometimes dangerous amounts.
In some countries, such as India and Sri Lanka, hydrogen sulfide
is produced in the process by which coconut fibres are separated from
the husk. This procedure involves the decomposition of the husks in
shallow ponds. The hydrogen sulfide is produced as a result of
microbiological decay processes.
to 80 g/kg and, occasionally, conditions arise in which hydrogen
sulfide is formed within such deposits. Thus, special precautions must
be taken in some mining operations as well as in the drilling and
extraction of natural gas and crude oils with significant sulfur
content.
Hydrogen sulfide can also be released by activities surrounding
the development and use of geothermal resources. At the Cerro Prieto
geothermal power generating plant in Baja California, Mexico, for
example, hydrogen sulfide levels are sufficiently high to necessitate
special ventilation to protect electrical systems, and alarms for the
protection of personnel (Mercado, 1975).
During industrial operations, hydrogen sulfide can be formed
whenever elemental sulfur or certain sulfur-containing compounds come
into contact with organic materials at high temperatures. It is
usually produced as an undesirable by-product, though it is also used
as an important reagent or desirable intermediate compound in some
industrial processes such as the manufacture of sulfides, sodium
hydrosulfide, and various organic sulfur compounds. Examples of
processes in which hydrogen sulfide occurs as a by-product include the
production of coke from sulfur-containing coal, the production of
carbon disulfide, the manufacture of viscose rayon in the Kraft
process for producing wood pulp (Macaluso, 1969) and sulfur extraction
by the Frasch process.
In refining sulfur-containing crude oils, about 80%-90% of the
divalent sulfur compounds of hydrogen and carbon are converted to
hydrogen sulfide. Both the hydrogen sulfide produced and that
occurring in other industrial, geothermal, or natural gas streams can
be recovered by one of a number of processes that can be classified as
either absorption-desorption processes or processes involving
oxidation to oxides or to elemental sulfur. The bulk of hydrogen
sulfide recovered in industrial processes is used to produce elemental
sulfur or sulfuric acid (Macaluso, 1969).
Large quantities of hydrogen sulfide are used in the production of
heavy water, which is employed as a moderator in some nuclear power
reactors. The process is based on enrichment of the deuterium content
of water by hydrogen sulfide in a gas/liquid ion exchange system,
followed by separation of heavy water and water by fractional
distillation (McGraw-Hill Encyclopedia of Science and Technology,
1960).
In the tanning industry, hydrogen sulfide is produced in the
process by which hair or wool is removed from the hides. This
typically involves deliming by adding ammonium chloride or ammonium
sulfate followed by pickling with sulfuric acid, and takes place in
large rotating drums. The gases evolved, including hydrogen sulfide,
are released from the drums on opening the hatches either to add
chemicals or to unload the treated hides, and also from the waste
waters (ILO, 1971).
As in the natural environment, hydrogen sulfide can be generated
by bacterial action in industrial or community settings in malodorous
and sometimes dangerous amounts.
In some countries, such as India and Sri Lanka, hydrogen sulfide
is produced in the process by which coconut fibres are separated from
the husk. This procedure involves the decomposition of the husks in
shallow ponds. The hydrogen sulfide is produced as a result of
microbiological decay processes.