C H E M I C A L S
Dendritic Salt Goes Into Production Morton will market salt with
star-shaped crystals, foresees their use in dye and detergent
Morton Salt, Chicago, 111., will soon be offering a new type of
salt. Un-like regular vacuum or flake salt, it has a s tar like
crystal structure. The new sodium chloride is called dendri-tic. It
is made by treating brine with a chemical that causes the crystals
to grow at the corners instead of at the faces and edges, according
to John M. Page, Morton's technical service man-ager.
Currently used in developmental quantities as a bulking agent in
tex-tile dyes, dendritic could find applica-tions in industrial
detergents and soaps, explosives, dry bleaches. The company is now
making the salt at its Silver Springs, N.Y., plant, plans to start
furnishing it commercially on June 1. Price will be on a par with
other high purity salts, Morton says.
Dendritic salt is produced from chemically purified brine by a
vacuum evaporation process. The process was developed in England by
Imperial Chemical Industries, Ltd., which was looking for a low
bulk density salt. Morton has been negotiating with ICI, now has an
exclusive license for mak-ing dendritic salt in the U.S.
Controlled Growth. In the con-ventional vacuum evaporation
method for making salt, Mr. Page explains, the brine is treated
with sodium hydroxide and sodium carbonate to remove cal-cium and
Then it passes to vacuum pans, where hot steam brings the brine
to boiling. Salt crystals form and remain in sus-pension until they
grow large enough to sink to the bottom of the pan, where they are
pumped off as a slurry. This slurry is washed and the crystals
filtered out. Finally, the salt is dried, screened, and
To produce dendritic salt, the con-ventional process must be
the crystal growth stage. Here, Mor-ton introduces sodium
ferrocyanide in aqueous solution to the salt as it crys-tallizes in
the vacuum pans. The chemical is adsorbed on the faces of the
vacuum salt, retarding growth at the faces and edges. Growth can
only take place then at the corners of the crystal, Mr. Page points
out. As a re-sult, the crystals are 3 dimensional, have a branched
or starlike appear-ance.
The finished product is finely granu-lated like vacuum salt;
yet, like flake salt, it has relatively low weight per unit volume.
Its bulk density ranges from 55 to 60 lb. per cu. ft., compared to
71 to 77 for vacuum salt and 45 to 65 for flake. Purity is 99.9%
sodium chloride, with less than 100 p.p.m. cal-cium and magnesium
impurities. Den-drite's properties include:
Relatively high specific surface which gives fast
Good blending ability.
Large capacity for absorbing moisture without becoming wet.
Good storing quality without caking.
Shape Pays Off. Dendritic salt is now used in developmental
quantities in the textile industry for dry blending or
standardizing concentrated dyes. In this application, it is mixed
with the dyefrequently in ratios as high as 1:1. The mixture is
weighed out and ap-plied as a percentage of the textile materials'
weight. Since the dye is used in this way, any variation in
con-centration of the dry mixture would greatly affect the
resulting color on the textile.
Here is where dendritic has several advantages over cube or
flake salt, Mr. Page says. For one, dendritic blends well, doesn't
separate out as easily as conventional salts, even in handling and
shipping. This property prob-ably stems from the shape of the
crys-tal. Dendritic has an irregular sur-face, doesn't reflect
light like cube salt. So it doesn't give what the dye-ing industry
calls the "salt and pepper effect."
The salt's properties of free flow and rapid water solubility
are also big advantages to textile dyers. Dyes in-corporated with
dendritic store much better than those containing cube, or flake
salts, according to Mr. Page. Also, dendritic is a fragile salt,
thus processes well in blending or mixing equipment.
Morton foresees many more appli-cations for dendritic. Potential
uses include bulking agents in industrial detergents and soaps or
in dry bleaches, most of which now use vacuum salt. It could
replace flake salt now used in explosives.
Three organic intermediates have been added to the line of
Pfister Chemical Works, Ridgefield, N.J. They are
2,4,5-trichloronitrobenzene, a yellow crystalline solid, insoluble
in water and alcohol but soluble in carbon disulfide;
2,4-dimethoxy-5-chloiOnitrobenzene, a light yellow powder with a
melting point range of 121 to 124 C. and soluble in chloroform and
ether; and yg-naphthylamine, white to reddish flakes with a minimum
purity of 98.5% and a melting point range of 110 to 112 C. C I
CRYSTAL STRUCTURES. Although magnifications differ slightly, the
photomicro-graphs clearly indicate the difference in structure
between Morton's star-shaped dendritic (left) and conventional salt
48 C & E N M A Y 1, 1961
phospho-nate, an insecticide for use against household insects, can
be formulated as an oil spray, an emulsion, or a wet-table powder.
Developed by Wiscon-sin Alumni Research Foundation, it will be
manufactured and distributed by Prentiss Drug and Chemical Co., New
York, N.Y. Butonate has very low mammalian toxicity, and its
rela-tively light odor is easily masked, the company says. C 2
Two sheeting grade polypropylenes, with a melt index of 0.6, are
available from En jay Chemical, New York, N.Y. Escon 502 is a
general purpose sheet-ing grade; Escon 522 is a long-term, heat
aging grade, designed for service at high temperatures for long
periods. They are expected to find use in fabri-cating objects with
large surface areas.
Column packing for gas chromato-graphic analysis of
triglycerides is available from Applied Science Lab-oratories,
Inc., State College, Pa. In addition, three products have been
added to the company's line of high purity (99%) fatty acid
derivatives. They are ethyl starate, ethyl palmi-tate, and ethyl
caproate, all of which are for use as gas chromatography standards.
Acetophenone, technical grade, with a purity of 97.1% is being
produced by Union Carbide Chemicals, New York, N.Y. This new grade
will allow cost savings in many noncritical ap-plications, such as
the manufacture of corrosion inhibitors, resins, and dyes, Carbide
says. C 5
Gluconic acid and sodium gluconate are now available in
commercial quan-tities from Industrial Biochemicals, Inc., Edison,
N.J. The sodium glu-conate is spray dried, comes as free-flowing,
low dusting granules that dis-solve rapidly. The gluconic acid is
available as a 50% yellow solution.
WHITE OILS Well within proposed purity standards under the
Delaney Amendmentthese s table,
non-polar hydrocarbon oils a re precisely refined, with
spectrophotometr ic control of light stability and purity. Our
process eliminates mi-nute impurities, even down to 1 or 2 parts
Penn-Drake White Oils are odorless, colorless, non-reac-tive,
fluid at low temperature and relatively low in cost. All Drakeol
grades comply fully with U.S.P. and N.F. require-ments. Write for
samples, de-tailed specifications, prices or a recommenda t ion for
a specific application.
drake ; product ,
PENNSYLVANIA REFINING COMPANY BUTLER 28, PENNSYLVANIA Branches:
Cleveland, Ohio and Edgewater, N.J.
M A Y 1, 1961 C & E N 49
I ll I EN9EL1I ^
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CHEMICALSDendritic Salt Goes Into Production