LECTURE NOTEPetrochemicals

LINEAR ALKYL BENZENE(LAB)

(Unit I)

Dr A K GuptaHead, Chemical & Biotechnology DivisionIndian Institute of PetroleumDehradun - 248001

LINEAR ALKYL BENZENE (LAB)(Detergent Alkylate)

LINEAR ALKYL BENZENELinear alkyl benzene (LAB) is the primary raw material used to produced LAB sulfonate (LAS), a surfactant detergent intermediate.LAB global demand is about 2.7 million tonnes per year.Its growth is mainly expected in the less developed countries.

Traditional processes for LAB production include an alkylation unit with liquid catalysts, which depending on the process, may include the following:

Alkylation of benzene with olefins C10-C14 in presence of HF.Alkylation of benzene with chloroparaffins C10-C14 in presence of AlCl3.Alkylation of benzene with olefins C10-C14 in presence of AlCl3.

Now-a-days most of LAB is produced from linear internal olefins and majority of commercial applications worldwide are based on HF catalyst.

RAW MATERIAL FOR LABBenzenePetroleum or natural gas based paraffins/olefins.Paraffins from keroseneOlefins from wax crackingOlefins from ethylene.

Chemical Reactions (Linear Alkyl Benzenes)(1)

(2)

(3) Reaction with Diolefins:Contd

Heavier components are formed by combination of reactions (1), (2),and (3).

Olefin Reaction with HF:

Polyalkyl benzenes, indanes and tetralines are typical compounds produced by benzene side reactions.

Branched alkylbenzene and oligomers, which are precursors of tars, coke are usually produced by olefin side reactions.

CATALYSTS-Strong Catalysts : AlBr3, AlCl3, HF.BF3Product distribution same at room temperature or higher (35-37C).

Weak Catalysts:HF, H2SO4, AlCl3.H2SO4, AlCl3 at low temperature.Product distribution depends upon:Chain lengthLocation of double bondRatio of reactants.Type of solvent (ratio also).Temperature.Homogenity of reaction medium.

Akylation of Benzene with 1-DodeceneaWHSV set to 0.5 to obtain 100% conversion. bincomplete conversion. c2 pH/4pH ratio, 6 pH not detected.

DETERGENT ALKYLATEProduced by reaction of -olefins or internal olefins with benzene using AlCl3, HF or Conc. H2SO4 as catalyst.

The reaction is conventional Friedel-Crafts Alkylation, highly exothermic reaction usually carried out in liquid-phase.

Olefin concentration is kept low to minimize side reactions and control temperature.

High Bz/Olefin ratios preferred to obtain high selectivity to mono alkylation.

Process for Detergent Alkylate Production

Commercial process for the production of LAB

LATEST LAB DEVELOPMENT

PACOL Catalyst and operation conditionsALKYLATION Solid Catalysts, Zeolites, clays, resins.

REACTION IN HETEROGENEOUS FIXED-BED REACTORS=> UOPs DETAL Process

ALKYLATION WITH SOLID CATALYSTSSeveral solid catalysts, zeolites, clays, heteropolyacids, sulfated ziroconia, immobilised ionic liquids were tested.

=> not commercially exploited so far.

Benzene alkylation with C10-C13 olefins

An important breakthrough was achieved by UOP in 1992New catalyst jointly with CESPAFluorinated silica-aluminaThe process is known as DETAL process.

The catalyst SiO2/Al2O3 ratio is 65/35 to 85/15, impregnated with HF.

The finished catalyst contains 1-6%.

Table : LAB by Delta process

DETAL process was tested in Petresas demonstration unit in Spain in 1992.

Three LAB plants use this technology.

Table : Operating Requirements per ton of Lab (ARC) Process

Operating Requirements per ton of Lab (EUTECO IMPIANTI S.P.A. Lab process)The linear alkyl benzenes product has the following typical properties

BromineMax. 0.03Colour hazenMax. 10Biodegradability OECD% 97Acidity (as ppm H2SO4)Max. 10

Raw materials: n-Paraffins Benzene Chlorine vapour750 kg.360 kg.380 kg.By Products Hydrochloric acid Heavy alkylates360 kg.70 kg.Utilities Steam Power Cooling water Fuel oil1000 kg.60 kWh200 m31.7 MM

Table : Yields in HF Alkylation for the production of detergent alkylate (UOPDetergent alkylate process)Contd

Alkylbenzene starting with n-paraffinsCHARGE STOCK

Linear paraffins, 98.5 wt% purity Benzene, 99.9 wt% purity

Total

MATERIAL PRODUCEDHydrogen, 96 mol % purityLight endsHF regenerator bottomsDetergent alkylateHeavy alkylate

Total Produced:Weight per 100 weights of linear detergent alkylate

82.934.4

117.3

1.13.82.8100.09.6

117.3

Contd

PRODUCT QUALITY: The linear alkylbenzene product has the following typical properties.

Comparison of the conventional HF alkylation with the alkylation using solid polymer catalyst.

GROWTH OF LAB IN INDIA

Company-wise LAB plants with capacities, 2001-02Source: Department of Chemicals & Petrochemicals, Ministry of Chemicals & Fertilizers, Govt. of India, New Delhi.tons

Highest capacity of LAB plant was of RIL. After acquiring 26 percent of Governments stake of IPCL in May 2002, LAB capacity of RIL has risen to 1,43,500 tons, increasing its market share from 32 percent to 46 percent.

Trends in consumption of LAB during the period 1979-80 to 2000-01Source: Department of Chemicals & Petrochemicals, Ministry of Chemicals & Fertilizers, Govt. of India, New Delhi and Monthly statistics of Foreign Trade in India, Part I & II, Mar 1980 to March 2001 (Directorate General of commercial intelligence & statistics, Calcutta).tons

Consumption of LAB was 318439 tons in 2000-01 as compared to its production of 356038 tons. With the rapid growth in demand for synthetic detergents, its is expected that the demand for LAB, which is the main raw material for synthetic detergents, will also grow commensurately.

Projected demand and supply gap of LAB during the period, 2001-02 to 2005-06Source : The Economics Department, Petrochemicals Data Service, Vadodra000 tons

Trends in exports and imports of LAB, 1990-91 to 2000-01Source: monthly statistics of Foreign Trade in India, Part I & II, Mar 1991 to Mar; 2001 (Directorate General of Commercial Intelligence & Statistics, Calcutta).tons

Indias Exports of LAB by countries, 1999-2000 and 2000-01Source: monthly statistics of Foreign Trade in India, Part I , Mar 2000 to Mar; 2001 (Directorate General of Commercial Intelligence & Statistics, Calcutta).

Inidias Imports of LAB by countries, 1999-00 and 2000-01Source: monthly statistics of Foreign Trade in India, Part II, Mar 2000 to Mar; 2001 (Directorate General of Commercial Intelligence & Statistics, Calcutta).