|
HYDROXY
ETHYL CELLULOSE-INVESTMENT OPPORTUNITY
Hydroxyethylcellulose
(HEC) is a nonionic, water soluble polymer that can thicken, suspend,
bind, emulsify, form films, stabilise, disperse, retain water and
provide protective colloid action. It is used to prepare solutions
with a wide range to viscosities. Also, it has outstanding tolerance
for dissolved electrolytes.
Because HEC is nonionic, it can be dissolved in many slat solutions that do
not dissolve other water soluble polymers.
However, as with most water soluble thickeners, the particles have a tendency
to agglomerate, or lump, when first wetted with water. This is
especially evident when the HEC is added to water with poor agitation.
Manufacturers have eliminated the problem of lumping and slow dissolving by
surface treating the particles, most commonly with glyoxal. When
added to water, the particles completely disperse. After an initial
induction period, commonly termed the delayed hydration time,
the dispersed particles begin to dissolve producing smooth, lump
free solutions.
Most manufacturers supply dispersible grades.
This article discusses the manufacturing process,
technology developments, Indian demand supply scenario and Indian
import/export level for
Hydroxyethylcellulose.
INDIA READY FOR MONITORING MEDICINES
In two
months, 30 centres will be set up in India to monitor side-effects
of prescription drugs.
Many
drugs are monitored abroad, but differing climatic and physical
conditions mean that such data is not completely applicable to
Indians.
DEHYDRATION OF ALCOHOLS
Alcohols such as Ethanol, Isopropanol, Butanol,
etc. form Azeotropes with water and are difficult to obtain in
anhydrous condition.
The usual method is to add a third component such
as Benzene or Cyclohexane to obtain a Ternary Azeotrope, which
is then processed to recover the anhydrous product and the third
component is recycled.
Extractive distillation is another method that
has been tried in the past. Extractive distillation is done using
a high boiling solvent that has the ability to alter the relative
volatility in favour of the product i.e. improves the separation
between the alcohol and water. There are other requirements also.
A process has been developed based on theoretical
study that uses the technique of extractive distillation. The
theory has been validated by laboratory scale experiments. The
solvent is an imported proprietary solvent. It is a safe solvent
with high flash point and low toxicity.
The process indicates significant savings over
the currently practiced processes. For a given capacity for anhydrous
ethanol, the physical size of the plant is smaller, which translates
to lower capital cost. In other words, revamping of an older plant
will give a higher capacity of 25 to 50%.
The energy consumption is lower. For example for
ethanol, the steam consumption mentioned in the literature is
1400 kg per 1000 liter of rectified spirit. In the present process
it would be about 700 kg.
Expertise has been developed to predict separation
of more complex mixtures involving three components that form
one or more binary azeotropes and also a ternary azeotrope. The
components could be alcohols, aromatic or aliphatic hydrocarbons,
water, ketones, esters, etc.
SPOTLIGHT OF SPECIALITY CHEMICAL- METHANE SULPHONIC ACID
Methane Sulphonic Acid (MSA) is well known for its useful properties as
a catalyst for esterification. It is used industrially to produce
acetates, acrylates, phthalates, adipates, fatty acid esters and
thioglycolates but it can also be used for rosin polymerisation
or other specialised ester synthesis.
This
article discusses the application aspects and process technology
as well as Indian import/export trends for Methane Sulphonic acid.
|