Transcript Types of Reactions in Art and Artists` Materials

Types of Reactions in Art
and Artists’ Materials
Fall 2014
Chip Lajeunesse and Linda Patterson
Wheeler High School, Marietta GA
Double Replacement
Producing Acid-Free Paper
Wood pulp has natural acids; during production,
acid-free paper may be treated with a mild base usually calcium or magnesium carbonate which neutralizes the acids and prevents the
formation of additional acids.
H2SO3 + CaCO3  CaSO3 + H2O + CO2
http://www.catalogs.com/info/technology/what-is-acid-free-paper.html
Paper Making Continued
Much of the commercially produced paper today is
acid-free. This is not due to the neutralizers added,
but is largely the result of a shift from china clay to
chalk as the main filler material in the pulp. Chalk is
cheaper. It also reacts with acids and requires the
pulp to be chemically neutral or alkaline.
china clay
http://www.catalogs.com/info/technology/what-is-acid-free-paper.html
Paper Manufacturing Process:
Paper Making Continued
Another feature is sizing. Paper can absorb ink. Sizing is used on
fibers in order to reduce their tendency to absorb liquids; so ink
stays on the surface of the paper, instead of being absorbed. The
sizing additives mixed with the pulp must also be acid-free. Until
1980 mainly a rosin in combination with alum was used. When
the paper industry started using chalk instead of china clay as
filler, the paper chemistry had to switch to a neutral process.
Today mainly AKD (alkyl ketene dimer) and ASA (alkenyl succinic
anhydride) are used.
More Double Replacement
When acids in acid rain react with the stone/rock in
statues, salt, water, and carbon dioxide are formed:
H2SO4 + CaCO3  CaSO4 + H2CO3 then
H2CO3  H2O + CO2
Marble statues are made of calcium carbonate.
• When carbon dioxide and sulfur dioxide are in the
air as pollutants, paintings can be damaged.
• Some solid precipitates from double replacement
reactions are used as pigments.
Single Replacement
• Rust gets its brick-red color from iron (III)
oxide Fe2O3:
• Fe + H2O  Fe2O3 + H2
Synthesis
• Using acids to help egg dye adhere to eggs
Synthesis continued
• Copper patina: 2Cu + O2  Cu2O then
2CuO + CO2 + H2O  Cu2CO3(OH)2 (green↓)
• Plating metals on jewelry
Copper Patina (Why it turns green!)
Patina on statues (most notably the Statue
of Liberty [1]) is made of copper sheet:
"The formation of patina varies with
atmospheric conditions and may not even
form in exceedingly dry conditions.
Typically however, the “Statue of Liberty"
tint does not make its entrance until around
the 15th year or later. [2]”
Sources:
[1] http://www.unc.edu/~jnrandal/sol.pdf
[2] http://www.copperliquidpaint.com/Copper
Copper Patina Continued
“The composition of patina varies dramatically with
location and may contain significant amounts of copper
sulfate (CuSO4). One investigation (1932 [3]) of a 13
year old marine specimen found a composition of the
patina to be (CuSO4) 2.5%, copper carbonate (CuCO3)
12.8% and copper hydroxide (Cu(OH)2) 52.5%.“
Source:[3] Handbook of Copper Compounds and
Applications, H. W. Richardson, ed., CRC Press, Boca
Raton, FL 1997, p 156.
Synthesis
• Para red dye is used in the making of American flags.
• The final step of the reaction involves a “coupling” reaction with
either an amino containing aromatic ring or an alcohol-containing
aromatic ring (phenol – aromatic ring with a hydroxyl group). For
example, we can take the diazonium salt from p-nitroaniline and
base-treated 2-naphthol and form para red.
• Figure 7: Synthesis of para red from p-nitroaniline and 2-naphthol.
Combustion
• Using a torch in welding
• Using an oven in glass blowing
• Wood burning
Decomposition
• Sunlight breaks bonds in color molecules, causing them
to fade.
• Concrete is a durable building material for sidewalks,
paths and driveways. The pitted surface of concrete
can collect debris such as those from fallen leaves. As
the leaves decompose, they may leach plant dyes and
stain the concrete's surface. Carbohydrates in the
leaves break down, aiding in the carbon cycle.
C6H12O6  CO2 + dye
http://www.fs.fed.us/wildflowers/ethnobotany/dyes.shtml
• Several dyes are obtained naturally from plants
decomposing:
.)
Dye Color
Yellow Dyes
Orange Dyes
Red Dyes
Purple / Blue Dyes
Green Dyes
Gray Dyes
Brown Dyes
Black Dyes
Plant Common Name (Additional Colors)
Yarrow (green, black)
Honey Locust
Golden wild-indigo (green)
Tall cinquefoil (black, green, orange, red)
Pecan (brown)
Indiangrass (brown, green)
Western comandra (brown, yellow)
Prairie Bluets (brown, yellow)
Bloodroot (brown, yellow)
Sassafras (black, green, purple, yellow)
Eastern Cottonwood (black, brown, yellow)
Plains Coreopsis (black, green, yellow, brown)
Ozark chinkapin (black, yellow, brown)
Sumac (yellow, green, brown, black)
Chokecherry
Prairie Parsley (yellow, brown)
Slippery Elm (brown, green, yellow)
Black Willow (black, green, orange, yellow)
Indian blanket (black, green, yellow)
Hairy coneflower (brown, green, yellow, black)
Red Mulberry (brown, yellow, green)
Mountain alder (brown, red, orange)
Summer Grape (orange, yellow, black)
Black Locust (black, green, yellow, brown)
Butterfly milkweed (yellow)
Texas Paintbrush (green, red, yellow)
Basket flower (yellow)
Sagebrush (yellow, gray)
Stinging nettle
Goldenrod (yellow, brown)
Iris (black)
Butternut (brown)
Canaigre Dock (yellow, green, brown)
Prickly poppy (green, orange, yellow)
Texas Paintbrush (green, red, yellow)
Elderberry (yellow)
Downy Phlox (brown, green, yellow)
Northern Catalpa (brown, yellow)
Sumac (yellow, red, green, brown)
May-apple (brown, yellow)
Sand Evening Primrose (green, orange, red, yellow)