Dow Chemical Company, Midland, Michigan
First U.S. Producer of Synthetic Indigo
ColorantsHistory.Org
A History by Robert J. Baptista, revised December 3, 2008
Dow Chemical Company, Midland, Michigan
Photo:  
Dow Industrial Chemicals and Dyes, 1938
Herbert H. Dow, a Canadian-born chemist, established the Dow Chemical Company in 1897 to manufacture and sell bleach.  In 1900 the company merged with
the Midland Chemical Company and began selling bromide compounds extracted from the brines under the Midland plant.  German bromide producers slashed
their price of bromides in the U.S. in 1905 in order to stop Dow from exporting bromides to Europe. But Dow was able to purchase German-made bromides in
the U.S., ship them back to Europe and still sell them at a lower price than the German producers were charging.

In July 1915 Herbert H.Dow told the Federal Trade Commission that American chemical manufacturers could produce synthetic indigo as cheaply as the
Germans, who had a monopoly on the world’s most important dyestuff.  In the same year an indigo research laboratory was setup at Midland to develop a
commercially viable process.  Raw materials such as aniline were already being manufactured at Midland.  A breakthrough occurred when  Dr. Lee H. Cone, an
organic chemist from the University of Michigan, was able to increase the yield of the indoxyl intermediate in the Heumann process (U.S. Patent No. 1,211,413,
1917).  The product would be made as a paste with an indigo concentration of 20 percent.

The synthesis began with aniline which was reacted with sodium bisulfite and sodium cyanide to form N-cyanomethylaniline.  This was hydrolyzed to form
sodium phenylglycinate which was cyclized in alkali to give the indoxyl intermediate.  Air oxidation of indoxyl formed indigo:










The process was complex, involving many intermediate steps, so there were setbacks.  After several delays, actual production began in early 1917 at the rate
of 400 pounds daily.  The first shipment was made to the Proximity Manufacturing Company of Greensboro, North Carolina.  The production rate was gradually
increased to reach the capacity of the unit, 5,000 pounds daily, or 1.5 million pounds annually.  U.S. consumption at the time was about 3,000,000 pounds
annually, so Dow captured about 50 percent of the market.

Before World War I, indigo sold for about 14 cents per pound.  The British blockade of German shipping stopped the imports, driving the price to $1.50, more
than ten times higher.  Dow became the first U.S. manufacturer of the largest volume dyestuff in the world, with an annual consumption of 80,000,000 pounds.  
National Aniline and DuPont soon followed with their own production.  The German monopoly on dyestuff manufacture was finally broken.











A range of redder shade brominated indigos soon followed, including Midland Vat Blue R.  The 6, 6'-dibromoindigo compoiund was determined to be the major
component of Tyrian Purple, the celebrated "purple of the ancients".  Phoenicians obtained the natural dye from the mollusc
Murex brandaris.












In the 1920s, the Swiss dyestuff maker Ciba entered a licensing agreement with Dow Chemical allowing the production of some of its patented indigoid dyes at
Midland.  Dow also developed a range of anthraquinone vat dyes and by 1938 the product line consisted of:






















The chemical structures of the Dowanone anthraquinone derived vat dyes are illustrated below:

















Dowanone Blue BCS was indanthrone, discovered by the German chemist Rene Bohn in 1901.  This was the first vat dye of the anthraquinone series.  It can  be
synthesized by the fusion of 2-aminoanthraquinoe, with a mixture of sodium and potassium hydroxides and an oxidizing agent such as sodium nitrite.  
Indanthrone is less important today because of its sensitivity to bleaching.

Dowanone Blue GCD was the dichloro derivatve of indanthrone and had a greener shade and better resistance to bleach.

Dowanone Yellow GN was flavanthrone, also discovered by Bohn in the early 1900s.  Bohn fused 2-aminoanthraquinone with potassium hydroxide to obtain the
dye.  Due to poor lightfastness, this dye was mainly used with blue vat dyes to obtain green shades.

The Ciba dye range produced at Midland included halogenated indigo and thioindigo derivatives:

















Ciba Scarlet G was made by condensing thioindoxyl (oxythionaphthene) with acenaphthenequinone:








Bromination of Ciba Scarlet G yielded Ciba Red R.

Dow Chemical eventually discontinued the production of indigo and other dyes.  This may have occurred when Ciba transferred the indigoid dyes to a new plant
in Toms River, New Jersey in the early 1950s.  DuPont shut down its indigo unit in Deepwater, New Jersey in 1963, citing low-priced imports.
Buffalo Color Corporation, successor to Allied Chemical, was the last domestic producer of indigo, closing its plant in 2003.  Synthetic indigo is now mainly
produced in China and India.  The major end use is still denim for blue jeans.

Genencor International (Palo Alto, California) announced the
discovery of a biosynthetic route to indigo in 2002, which would avoid the environmental problems
associated with the chemical manufacture of the dye.  































References:

1) “Must Learn the Tricks of Trade”, Ogden (Utah) Standard, July 21, 1915

2) ”Dye Situation Relief in Sight”, New York Times, February 11, 1916

3) “Rival the Germans at Chemical Show”, New York Times, September 26, 1916

4) “Making Synthetic Indigo”, New York Times, February 27, 1917

5)
Dow Industrial Chemicals and Dyes, Dow Chemical Company, Midland, MI, 1938, pp. 65-67

6) Williams Haynes,
American Chemical Industry, Vol. III, D. Van Nostrand Co., New York, 1945, pp. 244-245

7) Don Whitehead,
The Dow Story, McGraw-Hill Book Co., New York, 1968, pp. 81-82
Indigoid Dyes
Anthraquinone Dyes
Ciba Blue 2B
Dowanone Blue BCS
Ciba Blue 2BD
Dowanone Blue GCD
Ciba Blue BR
Dowanone Yellow GN
Ciba Brilliant Blue BS
 
Ciba Red 3B
 
Ciba Red R
 
Ciba Scarlet G
 
Ciba Violet R
 
Indigo
 
Midland Vat Blue 5B
 
Midland Vat Blue R
 
Dow Chemical Dyes Made at Midland, 1938
Dow Chemical Ad for Indigo-1937
"Old as the Pyramids, New as the 20th Century"
Copyright © 2008 by ColorantsHistory.Org.  All Rights Reserved.
Indigo
6, 6'-Dibromoindigo (Tyrian Purple)
Dowanone Blue BCS (Vat Blue 4)                             Dowanone Blue GCD (Vat Blue 14)                         Dowanone Yellow GN (Vat Yellow 1)
             Ciba Blue 2B                                                                      Ciba Red 3B
5,5',7,7'-TetrabromoIndigo                                       5,5'-Dichloro-7,7'-dimethylthioindigo
Ciba Scarlet G
This rare 1950 era color film, with a missing sound track, showcases the Dow Chemical plant in Midland, Michigan.  The 21 minute film documents the daily
operations of the plant, including scenes of workers manufacturing chemicals and chemical products such as epsom salt, calcium chloride (Dowflake),
dyes, agricultural chemicals, saran wrap and styrofoam.  Fans of industrial movies will see manufacturing units, tank farms of hazardous chemicals,
railcars, and chemists in lab coats doing experiments surrounded by bubbling beakers.  The dye making scene shows two workers discharging blue dye
presscake from a wooden plate and frame filter press.

Source:  Internet Archive (www.archive.org).  Copyright free.
Dow Trade Ad in 1919 Announces the
Availability of Indigo.  Click to Enlarge.
Dow Trade Ad in 1919 Announces the
Availability of Midland Blue R.  Click to Enlarge.
Midland Plant Depicted in Paintings by Arthur Knighton-Hammond