PCE-II UNIT-III-B

8/18/2019 PCE-II UNIT-III-B

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1,4 Butanediol (HOCH2-CH2-CH2-CH2OH)

With increasing the demand of tetrahydrofuran and

polybutylene terephthalate; 1,4 Butanediol has receivedconsiderable interest during recent years.

It is exclusively used as an intermediate for themanufacture of a large number of chemicals and polymers.

1,4 Butanediol is also used in the manufacture ofbutyrolactone which is used in manufacture of n!ethyl"pyrollidone #$!%&; an important solvent used in petroleumand petrochemical industries.

It is also 'nding applications in textile, leather, food and

pharmaceutical industries.(lobal consumption of 1,4Butanediol is about )etrahydrofuran #*+.-&, butyrolactone #1*."-&,%olyurethane #11.-&, %olybutylene terephthalate# "+.-&,copolymer ethers# 4.-&and miscellaneous #*./-&.


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arious processes used for the manufactureof 1,4 Butanediol are2

3cetone and formaldehyde route

Butadiene oute via 3cetoxylationButadiene oute via chlorination route

!aleic anhydride route

%ropylene route


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Acetylene and formaldehyde route:

)his is involves catalytic reaction of

formaldehyde with acetylene in the presenceof copper based catalyst at 15556 and barto yield 1,4 Butynediol which is hydrogenatedin two stages.

In the 'rst stage hydrogen is carried out inthe presence of $i catalyst at 5556 to yield1,4 Butanediol.


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Catalytic Acetoxylation of Butadiene:

)his process involves catalytic acetoxylationof butadiene to yield 1,4 78iacetoxy"butenes which on subse9uent hydrogenationfollowed by :ydrolysis yield 1,4 Butanediol.


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Catalytic acetoxylation of Butadiene for production of 1,4 Butanediol


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Butadiene ia Chlorination: )his involves chlorination of butadiene and

hydrogenation of mixture of 1,4 dichloro"butene and *,4dichloro1butene.


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1,4-Butanediol throu!h "aleic anhydride #oute


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In another process maleic anhydride is 'rstconverted to ethyl maleate which issubected to hydrogenation followed byhydrogenolysis.

$ropylene #oute:

In this propylene is 'rst converted to allylalcohol .

:ydroformylation of allyl alcohol gives analdehyde which on hydrogenation gives 1,4Butanediol.


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6hloroprene#6:"


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Butadiene #oute: )he process involves chlorination of

butadiene in the gas phase at "55

6*555

6which produces a mixture of *,4dichloro1butene ? 1,4dichloro"butene.

)he latter isomeri>ed to *,4dichloro1

butene in the presence of cuprous chlorideat a temperature of 15"1"56.

8ehydrochlorination of *,4dichloro1butene in the presence $a@: yields

6hloroprene.


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%oodyear proce&&:

In three stage process.

In this propylene dimeri>ed in the presence oftripropylaluminium in combination with nic=elor platinum to yield "methyl1pentene.

In the second stage "methyl1pentene is

isomeri>ed to "methyl "pentene in thepresence of acid catalyst which is subse9uentlycrac=ed to produce isoprene and methane.


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'&oprene from $ropylene imer #oute


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'&outylene and methylal route:

In this process methanol is 'rst reacted withformaldehyde in the presence of acidcatalyst to yield methylal which is reactedwith isobutylene in the vapour phase to

produce isoprene.


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3cetylene route2

In the 'rst stage acetylene is reacted with

acetone in the presence of potash solution toproduce methyl butynol which on selectivehydrogenation in the presence of palladiumgives methyl butenol.

@n dehydration at atmospheric and atemperature of *5556 on alumina methylbutenol to yields Isoprene.

PCE-II UNIT-III-B

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