Dear Swami,

You can react trichloroacetic acid with thionyl chloride to furnish trichloroacetyl chloride. Alternatively, you can treat the carboxylic acid with oxalyl chloride to provide the corresponding carboxylic acid chloride.

Hoping this will be helpful,

Rafik

Many years ago, i tried the regular reaction between the free acid and thionyl chloride... However, because the trichloroacetic acid is stronger than the evolves gaseous HCl, the  reaction "equlibrate" and tej yields od the desired acyl chloride is poor.... I obtained good yields using the reaction between the trichloroacetic acid and benzoyl chloride, according to the procedure developed by the famous H.C. Brown (te same of the boranes research). see this paper:

J. Am. Chem. Soc., 1938, 60 (6), pp 1325–1328

Dear Swami,

From Wikipedia, the free encyclopedia

Trichloroacetyl chloride

Names

IUPAC nametrichloroacetyl chloride

Identifiers

CAS Number

76-02-8 

ChemSpider

6180 

Jmol 3D model

Interactive image

PubChem

6420

InChI[show]

SMILES[show]

Properties

Chemical formula

C2Cl4O

Molar mass

181.832 g/mol

Density

1.62 g/cm3 at 20 °C

Boiling point

117.9 °C (244.2 °F; 391.0 K)

Solubility

miscible with diethyl ether[1]

Thermochemistry

Std enthalpy of

formation (ΔfHo298)

-280.0 kJ•mol−1[2]

Hazards

Safety data sheet

Oxford MSDS

EU classification (DSD)

Toxic (T); Corrosive (C)

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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Infobox references

Trichloroacetyl chloride is the acyl chloride of trichloroacetic acid. It can be formed by reacting chlorine with acetyl chloride or acetaldehyde in the presence of activated charcoal. It is used in the manufacture of pharmaceuticals and plant protection compounds.[

Thanks all

To prepare Trichloroacetyl chloride from Trichloroacetic Acid treat trichloroacetic acid with either thionyl or oxalyl chloride Ref. text book of practical Organic Chemistry by A.I.Vogel