I believe he was captured at Prairie Grove December, 1862 with Adam’s Arkansas Infantry.

Alcany B. Mathews, Private, Company E, 3rd Regiment Arkansas Infantry, paroled for exchange January 14, 1863 at Springfield, Mo., no further records

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Alcaney Matthis, Private, Company A, Crawford’s Battalion, Arkansas Cavalry,* enlisted March 17, 1863 in Carroll County by Captain Bishop for the war, value of horse $185, equipments $25, recorded present on the March 17 to June 30, 1863 muster, no further records

* This Battalion subsequently became Harrell’s Battalion Arkansas Cavalry, which was also known as 17th Battalion Arkansas Cavalry

All the officers and men of this command enlisted in the infantry regiment under command of Col. Charles W. Adams, known as Adams’ Regiment, T. M. A., Aug. 9, 1862, and by special order of Lieut. Gen. Holmes all the men of that regiment were transferred to the command of Gen. Cabell, of which this is a part.

M317: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Arkansas

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Adams Arkansas Infantry

3rd Regiment, Northwest Division, District of Arkansas, was organized mainly from unwilling conscripts, and some outright Unionists, from various counties in northern Arkansas.[4] Colonel Samuel W. Peel was originally assigned to command the new 3rd Regiment, but he was superseded by Colonel Charles W. Adams, who had formerly commanded the 23rd Arkansas Infantry Regiment. The unit was transferred to Confederate service at Elm Springs, Arkansas, on September 12, 1862.[6] Most of the men who had remained loyal after the unit disintegrated [Prairie Grove] were reassigned to either the 27th Arkansas Infantry Regiment or Harrell's 17th Arkansas Battalion Cavalry.[7]
http://en.wikipedia.org/wiki/Adams'_Arkansas_Infantry_Regiment