A process comprising: (a) distilling a melt comprising crude alkanesulfonic acid to completely or partly remove low boilers, wherein the low boilers are drawn off at the top of a distillation column or of a one-stage evaporation apparatus and a material stream comprising alkanesulfonic acid, high boilers and residual low boilers is withdrawn at the bottom of the distillation column or of the one-stage evaporation apparatus, (b) sending the stream comprising alkanesulfonic acid, high boilers and residual low boilers into a melt crystallization as the starting melt to obtain crystals formed from the alkanesulfonic acid, hydrates of the alkanesulfonic acid or a mixture of both suspended in mother liquor, (c) performing a solid-liquid separation to remove the crystals from the mother liquor, and (d) optionally washing the crystals to remove mother liquor adhering to the crystals.

A process comprising: (a) distilling a melt comprising crude alkanesulfonic acid to completely or partly remove low boilers, wherein the low boilers are drawn off at the top of a distillation column or of a one-stage evaporation apparatus and a material stream comprising alkanesulfonic acid, high boilers and residual low boilers is withdrawn at the bottom of the distillation column or of the one-stage evaporation apparatus, (b) sending the stream comprising alkanesulfonic acid, high boilers and residual low boilers into a melt crystallization as the starting melt to obtain crystals formed from the alkanesulfonic acid, hydrates of the alkanesulfonic acid or a mixture of both suspended in mother liquor, (c) performing a solid-liquid separation to remove the crystals from the mother liquor, and (d) optionally washing the crystals to remove mother liquor adhering to the crystals.

A polymer and hydraulic fracturing fluid provide an improved ability to transport proppant. In an embodiment, a method of designing a hydraulic fracturing fluid includes calculating an elastic modulus of a polymer. The method also includes calculating a critical velocity of a hydraulic fracturing fluid comprising the polymer and proppant based on the elastic modulus of the polymer.

The invention relates to a process for purifying alkanesulfonic acids which comprises the steps of: (a) distilling a melt comprising crude alkanesulfonic acid (1) to completely or partly remove low boilers, wherein the low boilers are drawn off at the top of a distillation column (3) or of a one-stage evaporation apparatus and a material stream (7) comprising alkanesulfonic acid, high boilers and residual low boilers is withdrawn at the bottom of the distillation column (3) or of the one-stage evaporation apparatus, (b) sending the stream (7) comprising alkanesulfonic acid, high boilers and residual low boilers into a melt crystallization (9) as the starting melt to form crystals of the alkanesulfonic acid, of hydrates of the alkanesulfonic acid or of a mixture of both suspended in mother liquor, (c) performing a solid-liquid separation to remove the crystals from the mother liquor, (d) optionally washing the crystals to remove mother liquor adhering to the crystals.

New ionic thermal acid generator compounds are provided. Also provided are photoresist compositions, antireflective coating compositions, and chemical trim overcoat compositions, and methods of using the compositions.

New ionic thermal acid generator compounds are provided. Also provided are photoresist compositions, antireflective coating compositions, and chemical trim overcoat compositions, and methods of using the compositions.