Synthesis of phthalic acid

Preparation of phthalic acid

Preparation of phthalic acid

Preparation of phthalic acid

20 g of naphthalene, 10 g of mercuric sulphate, and 300 g of concentrated sulphuric acid are placed in a round bottom flask fitted with reflux condenser. The whole is warmed until the naphthalene has gone into solution. The reaction commences at 200-250° C and becomes vigorous at 300° C, a mixture of phthalic acid with some sulphophthalic acid and unchanged naphthalene passing over, together with the carbon dioxide, sulphur dioxide, and water. The distillate is collected in about 250 ml of cold water, and the distillation continued until the mass in the retort is nearly dry. The distillate is filtered and the precipitate washed with cold water and then dissolved in sodium hydroxide. Unchanged naphthalene is removed by filtration, and the phthalic acid then reprecipitated with hydrochloric acid. It is finally purified by recrystallisation from hot water or aqueous alcohol. It forms colourless plates. The yield is about 70%.

Preparation of organic compounds, E. de. Barry Barnett, 159-160, 1912


phthalic acid



InChI Key


Canonical SMILES


MeSH Synonyms

phthalate, phthalic acid, phthalic acid, copper salt, phthalic acid, dipotassium salt, phthalic acid, disodium salt, phthalic acid, monobarium salt, phthalic acid, monocalcium salt, phthalic acid, monoiron (2+) salt, phthalic acid, monolead (2+) salt, phthalic acid, monopotassium salt, phthalic acid, monoruthenium salt, phthalic acid, monosodium salt, phthalic acid, potassium salt, phthalic acid, potassium, sodium salt, phthalic acid, sodium salt, potassium hydrogen phthalate

Depositor-Supplied Synonyms

phthalic acid, 1,2-benzenedicarboxylic acid, 88-99-3, benzene-1,2-dicarboxylic acid, o-phthalic acid, o-dicarboxybenzene, o-benzenedicarboxylic acid, Pathalic acid, Acide phtalique, ortho-phthalic acid, Sunftal 20, phthals, Alizarinate, Naphthalinate, Phthalinate, Alizarinic acid, Phthalinic acid, Kyselina ftalova, Naphthalinic acid, o-Carboxybenzoate, o-Carboxybenzoic acid, o-Benzenedicarboxylate, Acide phtalique [French], Kyselina ftalova [Czech], Phthalate standard for IC, CHEMBL1045, CCRIS 1446, CHEBI:29069, HSDB 1339, XNGIFLGASWRNHJ-UHFFFAOYSA-N, NSC 5348, EINECS 201-873-2, BRN 0608199, PHTHALICACID, AI3-02409, 1,2-Propylene glycol, bis(isooctyl phthalate), F3110-2832, 1,2-Benzenedicarboxylic acid, 1-methyl-1,2-ethanediyl diisooctyl ester, M 2, Orthophthalic acid, 4kww, phthalsäure, ACMC-209qya, AC1L1AJQ, AC1Q1HCJ, benzene-1,2-dioic acid, WLN: QVR BVQ, 10197-71-4, DSSTox_CID_1484, PHTHALIC ACID, ACS, bmse000391, SCHEMBL1808, DSSTox_RID_76178, Phthalic acid-ring-UL-14C, UNII-6O7F7IX66E, BENZENEDICARBOXYLICACID, DSSTox_GSID_21484, 3,4-benzenedicarboxylic acid, MLS002152931, 442758_SUPELCO, 6O7F7IX66E, 04924_FLUKA, 80010_FLUKA, HMDB02107, P39303_SIAL, ZINC90750, NSC5348, 314110_SIGMA, MolPort-000-690-820, s164, 80010_SIAL, HMS3039E17, HMS3604J03, 402915_SIAL, NSC-5348, 29801-94-3 (potassium salt), 877-24-7 (mono-potassium salt), Tox21_200915, 4409-98-7 (di-potassium salt), 5793-85-1 (mono-calcium salt), ANW-39200, AR-1L0961, BBL023724, BDBM50080272, SBB058481, STL168879, 15656-86-7 (mono-barium salt), 33227-10-0 (mono-Ru salt), 10197-71-4 (hydrochloride salt), AKOS000118898, PHTHALIC ACID (CARBOXYL-13C), 827-27-0 (mono-hydrochloride salt), DB02746, LS-1890, MCULE-4747891013, RP22870, RTR-027988, CAS-88-99-3, 15968-01-1 (di-hydrochloride salt), NCGC00090869-01, NCGC00090869-02, NCGC00258469-01, 6838-85-3 (mono-lead(2+) salt), AC-14464, AJ-10847, AK116685, AN-20569, AN-24158, BP-21159, KB-59631, OR025173, OR183112, OR253495, OR331083, SC-67693, SMR001224528, AB1002491, FT-0622644, H2983, P0287, ST24031536, ST50192167, C01606, 21176-EP2269988A2, 21176-EP2270008A1, 21176-EP2275413A1, 21176-EP2284165A1, 21176-EP2284178A2, 21176-EP2284179A2, 21176-EP2287156A1, 21176-EP2292597A1, 21176-EP2292617A1, 21176-EP2295406A1, 21176-EP2295438A1, 21176-EP2298731A1, 21176-EP2301924A1, 21176-EP2301940A1, 21176-EP2305219A1, 21176-EP2305248A1, 21176-EP2305663A1, 21176-EP2305672A1, 21176-EP2311807A1, 21176-EP2311815A1, 21176-EP2311824A1, 21176-EP2314295A1, 21176-EP2371805A1, 21176-EP2374780A1, 21176-EP2374781A1, 21176-EP2374895A1, 4-09-00-03167 (Beilstein Handbook Reference), AB-131/40237186, I01-7091, 3B1-008717, 3B3-032742, 4401-64-3, InChI=1/C8H6O4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4H,(H,9,10)(H,11,12

Removed Synonyms

phthalate, p-Phthalic acid, Potassium biphthalate, Potassium hydrogen phthalate, TEREPHTHALIC ACID, phthalic acid, copper salt, Phthalic acid, sodium salt, phthalic acid, disodium salt, phthalic acid, monobarium salt, phthalic acid, monosodium salt, Phthalic acid, dipotassium salt, phthalic acid, monocalcium salt, phthalic acid, monoruthenium salt, CID1017, Phthalic acid, monopotassium salt, phthalic acid, monoiron (2+) salt, phthalic acid, monolead (2+) salt, PHTHALIC ACID, POTASSIUM SALT, phthalic acid, potassium, sodium salt, C032279, 877-24-7, PHT, 1,2-Benzenedicarboxylic acid, 1,1′-(1-methyl-1,2-ethanediyl) 2,2′-diisooctyl ester, 100-21-0, 72845-50-2, 91485-83-5, 94483-72-4

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