Hydrocarbon Processing - April 2022 - 59

Industry Pioneers
Phillips Petroleum was involved in concerted efforts to investigate
the uses of natural gas liquids (NGLs). Hogan and
Banks were studying processes by which propylene and ethylene
could be converted to valuable gasoline-like materials,
so they started investigating the use of catalysts to do so.
In June 1951, they were experimenting by adding a small
amount of chromium oxide to a nickel oxide catalyst and fed
propylene with a propane carrier through the catalyst-packed
tube. While pure nickel oxide yielded the expected product
of low-molecular weight hydrocarbons, the chromium-modified
catalyst produced a white solid-a new material, crystalline
PP. With this new discovery, they pivoted research
efforts from gasoline to plastics and used the chromium catalyst
to produce an ethylene polymer. Within a year, they created
the process for making HDPE-the safest, hardest and
most heat-resistant plastic created at the time using much
lower operating pressure than branched low-density PE.
Phillips launched their product as Marlex® in 1954.7
Their
invention revolutionized the consumer plastics industry and
launched Phillips, an oil company, as a manufacturer of polyolefin
plastics. HDPE is extensively used in packaging, commodity
plastics, toys, tools, furniture, auto parts and a variety
of other applications.
Hogan received the Pioneer Chemist Award and is credited
with 52 U.S. patents.8
Hogan and Banks together received the
Perkin Medal in 1987, the Heroes of Chemistry award by the
American Chemical Society in 1989 and were inducted into
the National Inventors Hall of Fame in 2001.9
KARL ZIEGLER
In 1953, German chemist Karl Ziegler
employed a catalyst consisting of a
mixture of titanium tetrachloride and
an alkyl derivative of aluminum to create
a high molecular weight, high melting
point and straight-chain PE. His
pioneering research with organometallic
compounds, which made industrial
production of high-quality PE possible,
won him the 1963 Nobel Prize in Chemistry, which he
shared with Giulio Natta.10
Ziegler's research established new polymerization reactions;
enabled the syntheses of durable, higher melting,
unbranched polymers; and laid the groundwork for several
useful industrial processes. He combined classical organic
chemistry with physical and analytical experimental methods
in his phenomenal work on polymerization reactions.
Ziegler began his work on carbon compounds and organometallic
chemistry during his professorship at the
University of Heidelberg, which he continued after joining
as the Director of the Max-Planck-Institut in Mülheim
in 1943.11
Between 1952 and 1953, Ziegler's research group
tested various organoaluminium compounds and discovered
that nickel was the cause of the chain-ending reaction. They
further investigated to find a reagent to suppress this chain
termination reaction, which led them to discover that titanium,
under mild atmospheric conditions, produced rigid,
high-melting unbranched PE.
Besides his work with organometallic compounds, he is
also known for his research in the field of radicals with trivalent
carbon and synthesis of multi-membered ring systems,
which earned him the Liebig medal in 1935.11
One of the
many awards Ziegler received was the reputed Werner von
Siemens Ring in 1960 for expanding the scientific knowledge
of and the technical development of new synthetic materials.10
Ziegler
was able to take his discovery to industrial markets.
By 1958, he was reaping the benefits of approximately
two dozen licenses.12
GIULIO NATTA
Giulio Natta, an Italian scientist and
chemical engineer, extended Ziegler's
method to other olefins. Based on his
own findings on the reaction mechanism
of polymerization, he developed
further variations of the Ziegler catalyst.
For his contribution to the field of high
polymers, he shared the Nobel Prize in
Chemistry with Karl Ziegler in 1963.13
Commercial Ziegler-Natta catalysts include many mixtures of
halides of transition metals, especially titanium, chromium,
vanadium and zirconium, with organic derivatives of nontransition
metals, particularly alkyl aluminum compounds.14
Natta's early research career focused on studying solids
by x-rays diffraction (XRD) and electron diffraction. He
later employed the same expertise to study catalysts and the
structure of high organic polymers. By 1938, he began investigating
macromolecules-polymerization of olefins and the
kinetics of subsequent concurrent reactions.15
In 1953, after
he received financial aid from the large Italian chemical company
Montecatini, he extended Ziegler's research on organometallic
catalysts to stereospecific polymerization.15
These
studies led to the development of isotactic PP, a thermoplastic
polymer of highly regular molecular structure with commercially
important properties of high strength and a high melting
point. In 1957, Montecatini produced this polymer on an
industrial scale at their Ferrara plant.15
Natta's creation was
commercially marketed as a plastic material by the name of
Moplen, as a synthetic fiber by the name of Meraklon, as a
monofilament by the name of Merakrin, and as packing film
by the name of Moplefan.15
Natta discovered new classes of polymers and used XRD to
determine the exact arrangement of chains in the lattice of the
new crystalline polymers he discovered. He created polymers
with sterically ordered structure-isotactic, syndiotactic and
di-isotactic polymers and linear nonbranched olefinic polymers
and copolymers with an atactic structure.
Natta is also known for his later research that led to two
different routes for the synthesis of new elastomers: by polymerization
of butadiene into cis-1,4 polymers with a high degree
of steric purity, and by copolymerization of ethylene with
other a-olefins (propylene), originating extremely interesting
materials such as saturated synthetic rubbers. Natta published
700 research papers of which about 500 focus on stereoregular
polymers. He also received several awards and has many patents
in different countries to his credit.15
Hydrocarbon Processing | APRIL 2022 59
Hydrocarbon Processing - April 2022

Table of Contents for the Digital Edition of Hydrocarbon Processing - April 2022
