Palladium on Activated Charcoal also known as Palladium on
Carbon (Pd on C) is a mild hydrogenation catalyst. It is
generally a catalyst of choice when the functional group to be
hydrogenated is a part of a molecule which has also got some
other functional group capable of getting hydrogenated. It is
also a catalyst of choice for getting a specific type of isomer.
It is therefore a catalyst for selective hydrogenation.
Further, it can also be safely used where the reaction
conditions are acidic, viz. where acetic acid is a solvent
or dilute sulphuric acid is an additive.
Different
grades of these catalysts are made for attaining better yield
and efficiency with different type of reactions.
Vineeth Chemicals makes four standard grades of Palladium on
Carbon which can meet requirements for all types of
hydrogenation reactions where palladium on carbon is recommended
catalyst. In each grade palladium loading can be made as per
customers requirements. For reasons of economy, it is quiet
customary to use the same catalyst for more than one cycle of
hydrogenation before it is sent to the manufacturer for recovery
of palladium metal for eventual reformulation of fresh catalyst.
However, if the nature of the reactants and the end products is
such that the catalyst gets deactivated or poisoned after one
cycle only, it is advisable to opt for lower palladium loading
viz. 1% or 2% instead of standard 5% or 10%.
The classification of the grades made by Vineeth Chemicals has
been done on the basis of
a) The type of carbon used
Note: Use of a specific grade of activated charcoal produced as
a result of a carefully
controlled process ensures prevention of wayward and unwanted
side reactions.
b) Nature of Palladium deposition
i.e. whether Palladium metal has been
deposited predominantly on outer surface of carbon or
whether Palladium metal
has been deposited deep into the pores of carbon particles.
A reference table has been annexed which shows which grade is
more suitable for a particular type of reaction. The
recommendation given in the table should however be taken as a
suggestive one and not an ultimate one. While selecting a
powerful grade of palladium on carbon, one should also give
consideration to other functional groups present on the
molecule.
In
general, V types of catalysts are more powerful than Z type.
However, Shelf Life of V type catalyst is only one month
from the date of manufacture whereas Shelf Life of Z type
catalyst is three months from the date of manufacture.
Vineeth Chemicals undertakes the job work of recovery of
Palladium metal from the spent Palladium catalysts, refining of
the metal recovered and its usage to make fresh Palladium on
Carbon Catalysts. Fresh catalyst equivalent to about 70% of the
expected Palladium metal content of the consignment of the spent
catalyst received can be delivered within three days of receipt
of the consignment and balance in due course of time.
Notable users of Palladium on Carbon catalysts are Pesticides,
Dyes, Drugs, Perfumery Compounds manufacturers besides host of
other fine chemical manufacturers.
While using dry form of the catalyst care should be taken to
ensure that it is not directly exposed to environment of
hydrogen. Also the dry form should not be mixed with anhydrous
methanol. In either case it may result into fire and explosion.
Similarly, for facilitating efficient recovery of Palladium
metal, use of filter-aid and similar substances should be
avoided during filtration as far as possible.
Palladium on carbon catalysts can also be used for
dehydrogenation reactions.
The
standard packing is 1 kg, 2 kg and 5 kg in dry as well as wet
form (i.e. with 50% LOD). The packing size however can be
tailored to customers specific requirements.
For further details please feel free to contact General Manager,
Vineeth Chemicals.
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